Octopus Skimmer Mods - Page 21

davidabrown66 · 05/14/2007, 11:49 AM

Ok, some interesting updates over the weekend. I went to my non-bored out venturi that had the original nipple for the venturi and it had been resized only to 1/8". I started off by taking air measurements with the new enkamat layers added, reamed out 3/4" output of pump to skimmer, etc. and I I got 19 SCFH which is pretty good considering the airway is still pretty restricted and the venturi waterway isn't reamed at all.

So, my ideas was to try and increase vaccum by reaming only part of the venturi with 5/8" in spade bit. The area would be the entire area of the 90 degree that the air input takes from nipple to exit on the original venturi leaving the restriction at the end just before the air/water enters the nw pump. I started with just reaming out 1/2" or so, and retested. I was now at 20 SCFH, good! I went the rest of the way just past where the asperating nipple is, and retested...12 SCFH!! OH nO!

So, I decided to fill the venturi completely with epoxy and redrill it, and reshape it back. Did that, and now I'm getting some bad sounds like a cavitation sound coming from the pump, air draw is about 10 SCFH, so still no go yet. I have a call in for another venturi, and this time I won't mess with the water dynamics, only drill out the nipple for 3/8" threaded nipple. I reall want to see if all things being equal, if the air draw is better with or without reaming with 5/8" spade bit. My plan is to have the most efficient vaccum in place by design, and then increase the water flow which should increase the vaccum as well.

The venturi's seem to be out of stock, so I'll be using my other modified one for now. Still getting 28 SCFH out of that one.

Thanks all, I'll have more measurements when the Kill-o-watt meter shows up.

Anyone know where to get a venturi in stock?

kroe · 05/14/2007, 04:46 PM

The stock venturi isn't worth ordering... I bet you can make one out of PVC in less than three tries that is significantly better than stock. You want about a 1/2" narrow section for these pumps. I bored my venturi that was at 45 scfh and
63 watts from 1/2" to 5/8ths and tried it - my air flow dropped to 38 scfh and my wattage went up to 85. I am thinking about trying to go even smaller than 1/2" just to see what happens.

davidabrown66 · 05/14/2007, 05:05 PM

Quote:

Originally posted by kroe
The stock venturi isn't worth ordering... I bet you can make one out of PVC in less than three tries that is significantly better than stock. You want about a 1/2" narrow section for these pumps. I bored my venturi that was at 45 scfh and
63 watts from 1/2" to 5/8ths and tried it - my air flow dropped to 38 scfh and my wattage went up to 85. I am thinking about trying to go even smaller than 1/2" just to see what happens.

Hey Kroe, I've been reading what you've done and the others before me. In fact, I've read each of the 5000+ posts on this so far, and I'm amazed at the performance differences with the in-sump models vs recirc models.

If I remember correctly, you went from a 1" to 1/2" back to 1", is that right? what size is the venturi input, and where did you drill it...at the 1" to 1/2" transition, or in the middle of the 1/2" or closer to the 1/2 to 1" transition to the pump input?

I'm going to toy with that some more, but I hate to test on something I can't back out of. It sounds like you would have to use a butane torch to heat up the metric threads in order to make the connections work, and I'd have to do that on the pump input side and the output side to the skimmer, and have it not leak, and make sure the ends still match up to the skimmer. So, I'm a bit out of my comfort area, I could see doing this on an in-sump model, but more hesitant on an external. So, I've ordered some metric to standard pvc in hopes of doing this with a back out plan. I don't know if the fittings will be the right ones, but I've ordered (2) 40/32 x 1" spigot-socket by MBSP and FBSP in hopes that I can create my own venturi the way you described.

I'm tempted to see if my performance goes up if I put this thing in my sump...if it can fit.

My goal is to get at least 35 SCFH, and anything above that is gravy.

klasiksb · 05/14/2007, 05:16 PM

This doesn't relate to what is being talked about now, but figured I'd throw my current thoughts on this skimmer from my experience so far.

I've modded my NW-200 with the following:

1. Ported out the elbow from the pump to the skimmer.

2. Drilled out the nipple on the black venturi and slipped in RO tubing

3. I tried various methods of the mesh mod, with limited and inconsistant results, so i'm back to the stock impeller.

I had the airline constantly hooked up to an air meter, more so for the valve effect for dialing in the skimmer. I've been plagued by overflowing skimmer cup every few days and it was not making me happy. A couple of days of nasty gunk washing right back into the tank.

I now have just a JG valve on the air line, and the valve is wide open. This has been very consistant now, no overflowing and it's still pulling lots of gunk. I had to raise the water level quite a bit to make up for the loss of processing rate. But figured making slightly less skimmate is ok, compared to dumping it back into the tank when the skimmer freaks out.

36hrs. with the air wide open (with flash)

ppurcell · 05/14/2007, 05:24 PM

When I was using a gate valve on my ASM instead of the stand pipe, whenever I would shut down my return pump, the water level in my skimmer compartment would rise and because of the gatevalve this would push the water level in the skimmer higher too. Resulted in a flooded collection cup every time so I went back to the stand pipe.

The other thing a gate valve isn't forgiving of is changes in the pump behavior. If the pump is not steady in the air/water ratio, then the water level in the skimmer will rise and fall and the skimmer will ether flood or produce no skimmate depending on whether it is pushing more or less water than when you set it up.

I notice that the watts on my kilowatt vary by almost 10% during the week. I'm not sure what the cause is, but I bet that would have a negative effect on the skimmer if I were still using a gate valve.

JCTewks · 05/14/2007, 11:09 PM

Quote:

Originally posted by ppurcell
When I was using a gate valve on my ASM instead of the stand pipe, whenever I would shut down my return pump, the water level in my skimmer compartment would rise and because of the gatevalve this would push the water level in the skimmer higher too. Resulted in a flooded collection cup every time so I went back to the stand pipe.

The other thing a gate valve isn't forgiving of is changes in the pump behavior. If the pump is not steady in the air/water ratio, then the water level in the skimmer will rise and fall and the skimmer will ether flood or produce no skimmate depending on whether it is pushing more or less water than when you set it up.

I notice that the watts on my kilowatt vary by almost 10% during the week. I'm not sure what the cause is, but I bet that would have a negative effect on the skimmer if I were still using a gate valve.

The wattage variations are prob from fluctuating line voltage...mine does that all of the time, and if you look at the volts they have changed.

ppurcell · 05/15/2007, 06:24 AM

my pump was running pretty steady in the 74-79 watt range, then yesterday after I wrote that last post I was looking at it and it had jumped up to 108. I'm going to have to open it up to make sure nothing has changed in the impeller housing.

davidabrown66 · 05/15/2007, 08:49 AM

Quote:

Originally posted by klasiksb
This doesn't relate to what is being talked about now, but figured I'd throw my current thoughts on this skimmer from my experience so far.

I've modded my NW-200 with the following:

1. Ported out the elbow from the pump to the skimmer.

2. Drilled out the nipple on the black venturi and slipped in RO tubing

3. I tried various methods of the mesh mod, with limited and inconsistant results, so i'm back to the stock impeller.

I had the airline constantly hooked up to an air meter, more so for the valve effect for dialing in the skimmer. I've been plagued by overflowing skimmer cup every few days and it was not making me happy. A couple of days of nasty gunk washing right back into the tank.

I now have just a JG valve on the air line, and the valve is wide open. This has been very consistant now, no overflowing and it's still pulling lots of gunk. I had to raise the water level quite a bit to make up for the loss of processing rate. But figured making slightly less skimmate is ok, compared to dumping it back into the tank when the skimmer freaks out.

36hrs. with the air wide open (with flash)

Klasiksb, I would say this relates, and would like to hear more about your airflow readings, and how you attached your mesh, what type of mesh, etc. It looks like you're pulling out some pretty dark stuff at least.

Thanks

carlos_fb · 05/15/2007, 10:04 AM

Quote:

Originally posted by davidabrown66
I think this is common with these skimmers. I get the same.

You may want to try cleaning up your skimmer and probably even giving it a vinager bath, try to re adjust the raiser pipe too, just my 2 cents...

klasiksb · 05/15/2007, 01:13 PM

davidabrown66, that is without the meshmod, just stock NW impeller. I tired the mesh and saw a slight increase in air intake, but it ran very inconsistantly so I took off the mesh.

I took off the flowmeter, but will clean it up and throw it back on to get some readings for you. But I think it is pulling very close to stock numbers.

It is very consistant now. I will take 'consistancy' over a little more 'power'. The skimmer is useless if it keeps overflowing and dumping what it pulled out, back into the water.

davidabrown66 · 05/15/2007, 02:25 PM

Quote:

Originally posted by klasiksb
davidabrown66, that is without the meshmod, just stock NW impeller. I tired the mesh and saw a slight increase in air intake, but it ran very inconsistantly so I took off the mesh.

I took off the flowmeter, but will clean it up and throw it back on to get some readings for you. But I think it is pulling very close to stock numbers.

It is very consistant now. I will take 'consistancy' over a little more 'power'. The skimmer is useless if it keeps overflowing and dumping what it pulled out, back into the water.

Ah, ok..I understand. I thought maybe your inconsistency was b/c of the way it was applied, and i was going to offer some suggestions. I'm curious what your stock #'s are. I suspect the recirc models draw less air stock with the pump being out of water, and other reasons. My stock numbers were about 6 SCFH.

squin · 05/15/2007, 04:12 PM

Quote:

Originally posted by davidabrown66
Ah, ok..I understand. I thought maybe your inconsistency was b/c of the way it was applied, and i was going to offer some suggestions. I'm curious what your stock #'s are. I suspect the recirc models draw less air stock with the pump being out of water, and other reasons. My stock numbers were about 6 SCFH.

My stock numbers were about the same, 7 SCFH with the gasket notched for the venturi.

I'm very interested in your Kill-A-Watt readings when you receive.

davidabrown66 · 05/15/2007, 04:27 PM

Ya, I should have it delivered today, and I'll take some readings tonight. I won't have another venturi until probably next week unless I make my own.

squin · 05/15/2007, 05:07 PM

Quote:

Originally posted by davidabrown66
Ya, I should have it delivered today, and I'll take some readings tonight. I won't have another venturi until probably next week unless I make my own.

If you go the make-your-own route please post you're results. Others have posted some spectacular results for their in sump skimmers, but I don't recall seeing anyone post results for a homemade venturi for the re-circ skimmers. If I had the sump space I would possibly go the in-sump route based on what I've read.

Any thoughts on how to work around the metric unions and remain leak proof on the re-circ skimmers running outside the sump?

outy · 05/15/2007, 09:58 PM

i will be letting you know about recircs very soon as mine will be here tomorrow

i just got the 250 and plan on modding heavy still retaining the external use.

i should get a air gauge i guess and the killawat

ppurcell · 05/16/2007, 06:50 AM

7 scfh is really low. I was getting 5 lpm (10.5 scfh) on my stock OTP-3000. I posted some pics a few pages back of how I implemented some of the mods discussed in this thread that can get you up to 25-29 scfh (75-80watts) and don't require any major mods to the pump housing or impeller.

There are a lot of other posts that will get you into the same range with more "adventuresome" mods.

I still plan to implement jctwerks recommendation of removing at least the first needlewheel and probably the second too. And also kroe's case mod on the output. Between the two I fully expect to reach 45 scfh or better and see my watt draw drop below 70.

davidabrown66 · 05/16/2007, 09:19 AM

Quote:

Originally posted by ppurcell
7 scfh is really low. I was getting 5 lpm (10.5 scfh) on my stock OTP-3000. I posted some pics a few pages back of how I implemented some of the mods discussed in this thread that can get you up to 25-29 scfh (75-80watts) and don't require any major mods to the pump housing or impeller.

There are a lot of other posts that will get you into the same range with more "adventuresome" mods.

I still plan to implement jctwerks recommendation of removing at least the first needlewheel and probably the second too. And also kroe's case mod on the output. Between the two I fully expect to reach 45 scfh or better and see my watt draw drop below 70.

Is this on your G3?

davidabrown66 · 05/16/2007, 09:25 AM

Sorry, G4?

I just got my Kill-a-watt meter yesterday and I'm only pulling 66-67 watts on my modified venturi reamed to 5/8" and a 3/8" airway, 3 layers of enkamat, top nw taken off, reamed out 90 elbow from pump output to skimmer body to 5/8" and getting 28 SCFH. I think the only way I'm going to reach the 30's and 40's for SCFH is to improve the venturi or create my own.

ppurcell · 05/16/2007, 09:32 AM

It is on my G4+, but I don't think the skimmer body matters much so long as you aren't introducing a lot of additional backpressure.

Both the NW200 and the G4 have 8" bodies and I think both are about 30" tall so that should pose much of a difference. I am using a 1" output adaptor on my skimmer. I'm not sure what the output on the NW200 is.

Did you grind out the output area in the impeller housing? That mod bought me a bit over 1 lpm (2-3 scfh) by itself.

My pics are on page 13, but I realized that I ground out the impeller housing after I posted those pics and I didn't take or post any pics after wards.

davidabrown66 · 05/16/2007, 09:51 AM

Quote:

Originally posted by ppurcell
It is on my G4+, but I don't think the skimmer body matters much so long as you aren't introducing a lot of additional backpressure.

Both the NW200 and the G4 have 8" bodies and I think both are about 30" tall so that should pose much of a difference. I am using a 1" output adaptor on my skimmer. I'm not sure what the output on the NW200 is.

Did you grind out the output area in the impeller housing? That mod bought me a bit over 1 lpm (2-3 scfh) by itself.

My pics are on page 13, but I realized that I ground out the impeller housing after I posted those pics and I didn't take or post any pics after wards.

I went back and looked at all of those posts again as well. I believe the ID/OD of the output to be metric, but would equate to roughly ID of 5/8 to 3/4" and the OD to be 1", but the threads don't match up if you try a standard fitting. I ground out everything to 5/8" so there would'nt be bottlenecks. If I could, I would go with 1" pipes as well and make a venturi with that, but the metric fittings are a PITA to convert.

I have another pump coming today as well as some metric to standard fittings so I may try an grind down the volute some more, and try 4 layers of enkamat although the pump is starting to clack more as I add layers, and create my own venturi. I'm also trying to get my hands on another stock venturi, but coralvue isn't responding to the vendors I'm trying to work through to get it.

ppurcell · 05/16/2007, 10:10 AM

I wouldn't bother with the stock venturi. You can make one that works better for $5 or less in parts from the plumbing department. You can use a 1" coupler, drill a hole through it, attach an airline hose, insert a 3/4 ring or a 1"to1/2" bushing and slide it over the intake and call it done; but I see yours is a recirc, are you running it externally? If so, then it's going to be more of a challange to make it water tight.

If I remember correctly, there is a 3/4" male hose thread to 19 or 20mm adaptor on the output of my pump which I replaced with a 3/4" hose to 3/4 MPT nylon adaptor. Once you get to 3/4 mpt, you can pretty much do whatever you want.

and I think both skimmers are 24" tall, not 30" as I posted before.

davidabrown66 · 05/16/2007, 10:21 AM

Quote:

Originally posted by ppurcell
I wouldn't bother with the stock venturi. You can make one that works better for $5 or less in parts from the plumbing department. You can use a 1" coupler, drill a hole through it, attach an airline hose, insert a 3/4 ring or a 1"to1/2" bushing and slide it over the intake and call it done; but I see yours is a recirc, are you running it externally? If so, then it's going to be more of a challange to make it water tight.

If I remember correctly, there is a 3/4" male hose thread to 19 or 20mm adaptor on the output of my pump which I replaced with a 3/4" hose to 3/4 MPT nylon adaptor. Once you get to 3/4 mpt, you can pretty much do whatever you want.

Yep, I still need it to be external, and I'm not sure if I have the same connections/fittings you do with a recirc. plus anything I do on the input side that changes the plumbing distance on the pump input from the skimmer to the pump I also have to do from the pump output to the skimmer body as well. I don't think any of the threaded parts are standard including the 2 unions on the skimmer body and the threaded input/output fittings on the pump. If I could re-order the whole bag of parts, which I might be able to do, I would be more inclined to make permanent adjustments, but don't want to have a skimmer offline indefinitely waiting for parts from coralvue.

davidabrown66 · 05/16/2007, 10:23 AM

Quote:

Originally posted by outy
i will be letting you know about recircs very soon as mine will be here tomorrow

i just got the 250 and plan on modding heavy still retaining the external use.

i should get a air gauge i guess and the killawat

I would definitely get both

squin · 05/16/2007, 11:01 AM

Quote:

Originally posted by davidabrown66
Sorry, G4?

davidabrown66,

I just got my Kill-a-watt meter yesterday and I'm only pulling 66-67 watts on my modified venturi reamed to 5/8" and a 3/8" airway, 3 layers of enkamat, top nw taken off, reamed out 90 elbow from pump output to skimmer body to 5/8" and getting 28 SCFH. I think the only way I'm going to reach the 30's and 40's for SCFH is to improve the venturi or create my own.

I'll take 28 SCFH at 67 watts any day of the week. I have already made the output elbow and impeller mod. I have not done much to my venturi. I've been afraid I would screw it up with no replacement.

Would you refresh my memory on exactly what you did to your venturi? Reading all your previous posts you have been through a number of iterations, some worked, some not so good. Its hard for me to tell what worked and what did not. Did you ream the venturi waterway all the way through to 5/8" or just to a certain point on the output of the venturi. If so, how far? Did you insert the 3/8" tubing all the way into the water flow stream (3/8" tubing blocks some of the water flow), or attach with a fitting? I believe I remember you are running external. Any drips or other gotcha's I should avoid?

As you said, venturi's are hard to come by, and finding metrics parts has been a challenge as well. I need to be sure I get it right the first time.

davidabrown66 · 05/16/2007, 12:12 PM

Quote:

Originally posted by squin
I'll take 28 SCFH at 67 watts any day of the week. I have already made the output elbow and impeller mod. I have not done much to my venturi. I've been afraid I would screw it up with no replacement.

Would you refresh my memory on exactly what you did to your venturi? Reading all your previous posts you have been through a number of iterations, some worked, some not so good. Its hard for me to tell what worked and what did not. Did you ream the venturi waterway all the way through to 5/8" or just to a certain point on the output of the venturi. If so, how far? Did you insert the 3/8" tubing all the way into the water flow stream (3/8" tubing blocks some of the water flow), or attach with a fitting? I believe I remember you are running external. Any drips or other gotcha's I should avoid?

As you said, venturi's are hard to come by, and finding metrics parts has been a challenge as well. I need to be sure I get it right the first time.

It's funny, my best venturi came from the one I thought I'd made a mistake with.

I'm using the completely reamed venturi waterway to 5/8" drilled with a 3/8" drill bit for a threaded 3/8" nipple which gives me a 5/16" ID for air draw and more stability than just an airline inserted into a drilled hole. I only found these clear/white nipples at mcclendons and it was where they keep there RO tubing and special plastic parts in those tiny bins. I will post pics soon so you can see. I used aquarium sealant on the threads and screwed it all the way in, and the union still screw all the way with these nipples, but anything larger in that hole would create a problem when tightening down the unions again, and best of all no leaks whatsoever. I would also buy the tubing that goes with this nipple.

Find the fittings you need, double check my drill sizes, go slowly, start with a smaller bit if not sure, drill straight so you do NOT create any beveling of the hole by moving the drill in circular motions, and use aquarium sealant not epoxy, b/c it's more forgiving if you need to pull it out and start over.

05/14/2007, 05:16 PM	#504
klasiksb Registered Member Join Date: Dec 2002 Location: wisconsin Posts: 1,281	This doesn't relate to what is being talked about now, but figured I'd throw my current thoughts on this skimmer from my experience so far. I've modded my NW-200 with the following: 1. Ported out the elbow from the pump to the skimmer. 2. Drilled out the nipple on the black venturi and slipped in RO tubing 3. I tried various methods of the mesh mod, with limited and inconsistant results, so i'm back to the stock impeller. I had the airline constantly hooked up to an air meter, more so for the valve effect for dialing in the skimmer. I've been plagued by overflowing skimmer cup every few days and it was not making me happy. A couple of days of nasty gunk washing right back into the tank. I now have just a JG valve on the air line, and the valve is wide open. This has been very consistant now, no overflowing and it's still pulling lots of gunk. I had to raise the water level quite a bit to make up for the loss of processing rate. But figured making slightly less skimmate is ok, compared to dumping it back into the tank when the skimmer freaks out. 36hrs. with the air wide open (with flash) __________________ Just a girl looking to build a little piece of heaven on earth, without killing it!

05/15/2007, 01:13 PM	#510
klasiksb Registered Member Join Date: Dec 2002 Location: wisconsin Posts: 1,281	davidabrown66, that is without the meshmod, just stock NW impeller. I tired the mesh and saw a slight increase in air intake, but it ran very inconsistantly so I took off the mesh. I took off the flowmeter, but will clean it up and throw it back on to get some readings for you. But I think it is pulling very close to stock numbers. It is very consistant now. I will take 'consistancy' over a little more 'power'. The skimmer is useless if it keeps overflowing and dumping what it pulled out, back into the water. __________________ Just a girl looking to build a little piece of heaven on earth, without killing it!

05/16/2007, 10:10 AM	#521
ppurcell Registered Member Join Date: Jan 2006 Location: Naperville, IL Posts: 2,911	I wouldn't bother with the stock venturi. You can make one that works better for $5 or less in parts from the plumbing department. You can use a 1" coupler, drill a hole through it, attach an airline hose, insert a 3/4 ring or a 1"to1/2" bushing and slide it over the intake and call it done; but I see yours is a recirc, are you running it externally? If so, then it's going to be more of a challange to make it water tight. If I remember correctly, there is a 3/4" male hose thread to 19 or 20mm adaptor on the output of my pump which I replaced with a 3/4" hose to 3/4 MPT nylon adaptor. Once you get to 3/4 mpt, you can pretty much do whatever you want. and I think both skimmers are 24" tall, not 30" as I posted before. Last edited by ppurcell; 05/16/2007 at 10:15 AM.

05/14/2007, 11:49 AM	#501
davidabrown66 Registered Member Join Date: Jan 2006 Location: Kent, WA Posts: 231	Ok, some interesting updates over the weekend. I went to my non-bored out venturi that had the original nipple for the venturi and it had been resized only to 1/8". I started off by taking air measurements with the new enkamat layers added, reamed out 3/4" output of pump to skimmer, etc. and I I got 19 SCFH which is pretty good considering the airway is still pretty restricted and the venturi waterway isn't reamed at all. So, my ideas was to try and increase vaccum by reaming only part of the venturi with 5/8" in spade bit. The area would be the entire area of the 90 degree that the air input takes from nipple to exit on the original venturi leaving the restriction at the end just before the air/water enters the nw pump. I started with just reaming out 1/2" or so, and retested. I was now at 20 SCFH, good! I went the rest of the way just past where the asperating nipple is, and retested...12 SCFH!! OH nO! So, I decided to fill the venturi completely with epoxy and redrill it, and reshape it back. Did that, and now I'm getting some bad sounds like a cavitation sound coming from the pump, air draw is about 10 SCFH, so still no go yet. I have a call in for another venturi, and this time I won't mess with the water dynamics, only drill out the nipple for 3/8" threaded nipple. I reall want to see if all things being equal, if the air draw is better with or without reaming with 5/8" spade bit. My plan is to have the most efficient vaccum in place by design, and then increase the water flow which should increase the vaccum as well. The venturi's seem to be out of stock, so I'll be using my other modified one for now. Still getting 28 SCFH out of that one. Thanks all, I'll have more measurements when the Kill-o-watt meter shows up. Anyone know where to get a venturi in stock?

05/14/2007, 04:46 PM	#502
kroe Premium Member Join Date: Apr 2004 Location: Wallingford, CT Posts: 1,211	The stock venturi isn't worth ordering... I bet you can make one out of PVC in less than three tries that is significantly better than stock. You want about a 1/2" narrow section for these pumps. I bored my venturi that was at 45 scfh and 63 watts from 1/2" to 5/8ths and tried it - my air flow dropped to 38 scfh and my wattage went up to 85. I am thinking about trying to go even smaller than 1/2" just to see what happens.

05/14/2007, 05:24 PM	#505
ppurcell Registered Member Join Date: Jan 2006 Location: Naperville, IL Posts: 2,911	When I was using a gate valve on my ASM instead of the stand pipe, whenever I would shut down my return pump, the water level in my skimmer compartment would rise and because of the gatevalve this would push the water level in the skimmer higher too. Resulted in a flooded collection cup every time so I went back to the stand pipe. The other thing a gate valve isn't forgiving of is changes in the pump behavior. If the pump is not steady in the air/water ratio, then the water level in the skimmer will rise and fall and the skimmer will ether flood or produce no skimmate depending on whether it is pushing more or less water than when you set it up. I notice that the watts on my kilowatt vary by almost 10% during the week. I'm not sure what the cause is, but I bet that would have a negative effect on the skimmer if I were still using a gate valve.

05/15/2007, 06:24 AM	#507
ppurcell Registered Member Join Date: Jan 2006 Location: Naperville, IL Posts: 2,911	my pump was running pretty steady in the 74-79 watt range, then yesterday after I wrote that last post I was looking at it and it had jumped up to 108. I'm going to have to open it up to make sure nothing has changed in the impeller housing.

05/15/2007, 04:27 PM	#513
davidabrown66 Registered Member Join Date: Jan 2006 Location: Kent, WA Posts: 231	Ya, I should have it delivered today, and I'll take some readings tonight. I won't have another venturi until probably next week unless I make my own.

05/15/2007, 09:58 PM	#515
outy Moved On Join Date: Oct 2004 Location: auburn CA Posts: 4,021	i will be letting you know about recircs very soon as mine will be here tomorrow i just got the 250 and plan on modding heavy still retaining the external use. i should get a air gauge i guess and the killawat

05/16/2007, 06:50 AM	#516
ppurcell Registered Member Join Date: Jan 2006 Location: Naperville, IL Posts: 2,911	7 scfh is really low. I was getting 5 lpm (10.5 scfh) on my stock OTP-3000. I posted some pics a few pages back of how I implemented some of the mods discussed in this thread that can get you up to 25-29 scfh (75-80watts) and don't require any major mods to the pump housing or impeller. There are a lot of other posts that will get you into the same range with more "adventuresome" mods. I still plan to implement jctwerks recommendation of removing at least the first needlewheel and probably the second too. And also kroe's case mod on the output. Between the two I fully expect to reach 45 scfh or better and see my watt draw drop below 70.

05/16/2007, 09:25 AM	#518
davidabrown66 Registered Member Join Date: Jan 2006 Location: Kent, WA Posts: 231	Sorry, G4? I just got my Kill-a-watt meter yesterday and I'm only pulling 66-67 watts on my modified venturi reamed to 5/8" and a 3/8" airway, 3 layers of enkamat, top nw taken off, reamed out 90 elbow from pump output to skimmer body to 5/8" and getting 28 SCFH. I think the only way I'm going to reach the 30's and 40's for SCFH is to improve the venturi or create my own.

05/16/2007, 09:32 AM	#519
ppurcell Registered Member Join Date: Jan 2006 Location: Naperville, IL Posts: 2,911	It is on my G4+, but I don't think the skimmer body matters much so long as you aren't introducing a lot of additional backpressure. Both the NW200 and the G4 have 8" bodies and I think both are about 30" tall so that should pose much of a difference. I am using a 1" output adaptor on my skimmer. I'm not sure what the output on the NW200 is. Did you grind out the output area in the impeller housing? That mod bought me a bit over 1 lpm (2-3 scfh) by itself. My pics are on page 13, but I realized that I ground out the impeller housing after I posted those pics and I didn't take or post any pics after wards.