Octopus Skimmer Mods

[davidabrown66]

Don't drill yet! Ok, I have to make a change to my last post. The nipple is actually 3/8" X 1/4". so the nipple is 3/8 and the threads are 1/4. This gives you the ID you're looking for without drilling a larger than needed hole, and a 3/8" hole would create problems if you have the recirc model and use the union fittings.

So, here's the part:

Watts - PL-326
PB225N
3/8" X 1/4"
Poly Barb to MIP adapter
$1.36

[davidabrown66]

OK,Ok,Ok, I'm a bonehead...I got home and tried the fitting I just bought the 3/8 x 1/4 and it's wrong...##@%$

So, I went to the hw store and bought the right one. It's a 3/8" x 1/8" watts connector: PL-325, Nylon barb to MIP adapter not 3/8 x 1/4" and the threads have nothing to do with that number..duh.

And to make matters worse the watts connector I just bought doesn't insert as well as my original venturi where I'm getting 28 SCFH, so this might effect others as well who are going to use this fitting. So, I would recommend drilling the 3/8" hole, try and use the barb fitting with aquarium sealant, and then if that doesn't screw in enough for you, I would buy the 3/8 x 1/8 tubing and use that as in previous posts.

I'm going to wait for things to dry, and see what the numbers are for the tubing, on my epoxy filled loud cavitation venturi that's only getting 15 SCFH.

On a side note, I received my metric fittings, but only one side of the fitting is threaded, and it looks like the union fittings are more likely closer to 1 1/4" standard, but in metric, and the pump side looks more like 3/4", but in metric, so not going to try my own venturi just yet.

I'll post #'s tomorrow AM

[kroe]

david - do you still have high water flow? If so decrease the diameter of the narrow section of the venturi.

Those watts connectors where the threaded part is smaller than the tube need to be modified to work well - you need to drill out the threaded part to the same ID as the tubing.

[klasiksb]

davidabrown66, cleaned up my air meter and with the air wide open i'm pulling 10-11 SCHF. My meter is in incraments of 10. If I recall correctly, the mesh mod only added a few SCHF to that, not the dramatic results others have saw.

[davidabrown66]

Originally posted by kroe
david - do you still have high water flow? If so decrease the diameter of the narrow section of the venturi.

Those watts connectors where the threaded part is smaller than the tube need to be modified to work well - you need to drill out the threaded part to the same ID as the tubing.

Yes, the internal diameter is the same size all the way through even though the threaded part is smaller than the barb. The ID is large enough to fit a normal sized RO tubing into it. That's pretty good, but I suppose I could drill out some more.

Thanks for the heads up.

[Bunkerbean]

Ok guys, I want to make my NW-150 better. I read the part on the #18 gasket. And then I decided that 62 pages was a lot to go through and figured maybe I could ask first.

Is there any thing else that can improve this skimmer?

[davidabrown66]

Originally posted by klasiksb
davidabrown66, cleaned up my air meter and with the air wide open i'm pulling 10-11 SCHF. My meter is in incraments of 10. If I recall correctly, the mesh mod only added a few SCHF to that, not the dramatic results others have saw.

I think the enkamat mod is more effective the larger you air input is. I was able to get 19 SCFH from my stock venturi when I reamed out both sides of the venturi just large enough to still use the nipple, and 3 layers of enkamat, modified 90 deg elbow on pump output, reamed out the pump volute, and gasket mod. It was at that point that I decided to see what the #s were if I reamed out the waterway of the venturi, and my numbers fell to 15 SCFH. Now, I'm wondering what my numbers would have been if I'd left that alone, and drilled the larger airhole for the 3/8 watts fitting. That's what I want to do with another stock venturi, and maybe add one more layer of enkamat.

Interestingly, I took another reading to see what my pump wattage is, and now it's only 58 watts, 60 Hz, 120 volts, 1.2 amps. And, my airflow is actually more like 26-27 SCFH.

I didn't have a chance to take #'s from the venturi I that's been epoxy filled and redrilled that now had 3/8 x 1/8 in tubing instead of the 3/8" barb b/c it kept slipping into the venturi hole when I went to put on the air hose, so this might not be for me unless epoxy works better. The problem is that we pull and push the airline tubing on, and without threads the tubing just slides in/out of the hole with minor force applied. Ideally you would use a tap to make the 3/8" hole for better threading, but I would still try the threaded fitting first and use the tubing if the threads don't seat well, and use a bunch of aquarium sealant or epoxy.

If you're only pulling 10-11 SCFH, then I would look at other restrictions from pump input to output and take a 5/8" spade bit, and match it up to all of your fitting just to make sure everything is at least this ID including the plumbing that came in the bag. Then, I would ream out the venturi at both end retaining the 90 deg turn and nipple, but do this carefully, blow into it and make sure it's completely clear of debree at both ends, and even use a flashlight to make sure you see light coming down, and cut the top set of pins off your impellar if you haven't already, and use 3 layers of enkamat tied tightly using fishing line.

I can't remember the particulars of what you've done, but with those numbers I suspect your airway is too restricted to fully take advantage of the enkamat mod.

[davidabrown66]

Originally posted by Bunkerbean
Ok guys, I want to make my NW-150 better. I read the part on the #18 gasket. And then I decided that 62 pages was a lot to go through and figured maybe I could ask first.

Is there any thing else that can improve this skimmer?

Yes, but I would still read thru the pages, b/c there's alot of info and pics that others have submitted that will help understand the mods.

Namely, increased airflow from stock venturi by reaming stock venturi, or drilling thru the venturi, or creating your own venturi, using enkamat for the mesh mod, cutting down your impellar for the mesh mod, reaming out the volute of the pump and the pump elbow for water flow, etc.

I would also get a Dwyer meter at least, and maybe a Kill-a-watt meter if you're concerned about pump wattage changes the mods might make.

The air meter is I think critical to seeing what each mod does to your performance. You won't hear the difference in the air hose for example if you increase/decrease the air draw by 5 SCFH which is a pretty large amount.

I can tell you though, if you do these mods your skimmer will increase in performance at least 300 - 500%, and will give you a skimmer that will perform on par with a Deltec/H&S/Euroreef and maybe a BM.

I started with an air draw of roughly 6 SCFH, and now I'm at 27. To reach a comparable Euroreef that's 30 in tall and 8 in body, I'm going for 45 SCFH which is about 1300 LPH.

[Bunkerbean]

David,

I am actually slowly going through the posts.

Where can I get the mesh?

I liked the Venturi mod Roland did and am going to try and duplicate it.

Any particular Dwyer meter? Where are most getting them.

"reaming out the volute of the pump and the pump elbow for water flow, etc"
I haven't seen this mod yet.


Thanks for the help.

[davidabrown66]

Originally posted by Bunkerbean
David,

I am actually slowly going through the posts.

Where can I get the mesh?

I liked the Venturi mod Roland did and am going to try and duplicate it.

Any particular Dwyer meter? Where are most getting them.

"reaming out the volute of the pump and the pump elbow for water flow, etc"
I haven't seen this mod yet.


Thanks for the help.

I know, it took me several hours to go through, and I have the newer recirc design so the first 4000 posts did'nt even apply to me.

I would look at ebay. I bought enough to do 4 layers, and the person only charged $5

You get the dwyer meters from them directly here:
https://www.dwyer-inst.com/htdocs/fl...iesRMPrice.cfm

You'll want the rma-7 which measures .5 - 50 SCFH ($24). You can convert LPH from SCFH using this:
7 LPM (430 LPH) = 15 SCFH. I got this from another post.

You have more options for your "in-sump" model, when it comes to making your own venturi, and plumbing in general, b/c your skimmer is in sump vs a recirc which is out of sump. the plumbing is different, and if your mod's leak a little who cares?

[Bunkerbean]

I bought the one on ebay. Thanks for the tip.


I will mod the existing venturi first, and hope not to mess it up.

I think I am going to stick the the O-ring, mesh, venturi mod.

If I do happen to create to much air. Is there like a gate valve I can get to restrict it?

[davidabrown66]

Originally posted by Bunkerbean
I bought the one on ebay. Thanks for the tip.


I will mod the existing venturi first, and hope not to mess it up.

I think I am going to stick the the O-ring, mesh, venturi mod.

If I do happen to create to much air. Is there like a gate valve I can get to restrict it?

That's a good idea, is what I did also.

There is a gate valve mod out there, and you can always attach an air valve on the end of the venturi airline to dial it back if needed.

[hounddog01]

The only mod I did to the venturi is to drill out the air hole and put a peice of RO line in there. I am going to even make it larger and see what happens. I started with stock pulling 10scfh and now with the mesh mod and venturi mod with ro line i am pulling over 20 (the meter only goes to 20 and it is pegged at the top). Both of these are simple and do not take more than an hour. After reading this thread and participating for several months I think these are the quickest mods with the best resulty. Reaming out the venturi I have seen bad resullts from this. You have to get it perfect with a larger air line. both have to be correct to get better results.

[Bunkerbean]

Reaming out the venturi I have seen bad resullts from this. You have to get it perfect with a larger air line. both have to be correct to get better results. [/B]

For your RO line what drill bit did you use?

[klasiksb]

Originally posted by davidabrown66
I think the enkamat mod is more effective the larger you air input is. I was able to get 19 SCFH from my stock venturi when I reamed out both sides of the venturi just large enough to still use the nipple, and 3 layers of enkamat, modified 90 deg elbow on pump output, reamed out the pump volute, and gasket mod. It was at that point that I decided to see what the #s were if I reamed out the waterway of the venturi, and my numbers fell to 15 SCFH. Now, I'm wondering what my numbers would have been if I'd left that alone, and drilled the larger airhole for the 3/8 watts fitting. That's what I want to do with another stock venturi, and maybe add one more layer of enkamat.

Interestingly, I took another reading to see what my pump wattage is, and now it's only 58 watts, 60 Hz, 120 volts, 1.2 amps. And, my airflow is actually more like 26-27 SCFH.

I didn't have a chance to take #'s from the venturi I that's been epoxy filled and redrilled that now had 3/8 x 1/8 in tubing instead of the 3/8" barb b/c it kept slipping into the venturi hole when I went to put on the air hose, so this might not be for me unless epoxy works better. The problem is that we pull and push the airline tubing on, and without threads the tubing just slides in/out of the hole with minor force applied. Ideally you would use a tap to make the 3/8" hole for better threading, but I would still try the threaded fitting first and use the tubing if the threads don't seat well, and use a bunch of aquarium sealant or epoxy.

If you're only pulling 10-11 SCFH, then I would look at other restrictions from pump input to output and take a 5/8" spade bit, and match it up to all of your fitting just to make sure everything is at least this ID including the plumbing that came in the bag. Then, I would ream out the venturi at both end retaining the 90 deg turn and nipple, but do this carefully, blow into it and make sure it's completely clear of debree at both ends, and even use a flashlight to make sure you see light coming down, and cut the top set of pins off your impellar if you haven't already, and use 3 layers of enkamat tied tightly using fishing line.

I can't remember the particulars of what you've done, but with those numbers I suspect your airway is too restricted to fully take advantage of the enkamat mod.

To tell you the truth, I'm tired of farting around with it and worrying if it's going to overflow or not. As long as it is running consistantly, it's going to stay this way.

[davidabrown66]

To tell you the truth, I'm tired of farting around with it and worrying if it's going to overflow or not. As long as it is running consistantly, it's going to stay this way. [/QUOTE]

Ah yes, I have seen others with this problem, and resolved it by using a baffle in the sump to set a consistent/desired water level, and then placed their skimmer in there, usually on a stand so the baffle can be positioned say 15 high, and the skimmer on a 7 in stand to give you a consistent water heighth of 8" for example. I haven't seen/heard of anyone having problems with overflowing b/c of the mods. It's been b/c of backpressure from the water level in the sump changing the outflow of water thru the gatevalve.

Anyway, I understand not wanting to fart around with it, if it's working well now. Just thought I'd throw that out.

[davidabrown66]

Got home last night and my wattage had stabalized at exactly 65 watts, not sure why that was so low before.

I tried the 3/8" tubing for a venturi on my epoxy venturi, but it leaked some around the tubing the numbers were only around 15 SCFH still. I'll try the tube when i can get another venturi.

I also tied the fourth layer of enkamat and my air draw stayed the same, and maybe even got a little lower, and my wattage went up to 70 so a little dissappointed there as well.

I've found a wholesale distributor for Spears parts so I can try and find some metric pvc to make my own venturi maybe next week.

I woke up this morning and went to the skimmer and saw really dry white foam already in the tower after cleaning the skimmer last night, so maybe the bubbles are actually finer with 4 layers...?

Am I overskimming to get dry white foam?

Anyway, I won't being doing anything until I can get/make another venturi.

If anyone locally needs to borrow my dwyer meter or Kill-o-watt meter for a week let me know.

[squin]

Originally posted by davidabrown66
Interestingly, I took another reading to see what my pump wattage is, and now it's only 58 watts, 60 Hz, 120 volts, 1.2 amps. And, my airflow is actually more like 26-27 SCFH.

davidabrown66,

I apologize for being thick headed, but with the many different variations on the theme I'm having a little trouble connecting the dots. Which venturi/impellar combo yielded the results above?

Thanks for your patience.

[davidabrown66]

Originally posted by squin
davidabrown66,

I apologize for being thick headed, but with the many different variations on the theme I'm having a little trouble connecting the dots. Which venturi/impellar combo yielded the results above?

Thanks for your patience.

Ah, for the venturi:

-Completely reamed waterway to 5/8"
-Drilled out venturi nipple straight through with 3/8" drill
-3/8" x 1/8" nylon barb watts connector

Impellar:

-Top row of pins cut off
-3 layers of enkamat = 65 watts
(not sure how many layers I like best yet)
-4 layers of enkamat = 70 watts
-10 lb test fishing line

All waterway going to/from OTP-3000 that was less than 5/8" was reamed to 5/8" with spade bit.

[mr. pluto]

for those who had the 3000 pump, did you notice the replacement
needlewheels are smaller?

[davidabrown66]

Originally posted by mr. pluto
for those who had the 3000 pump, did you notice the replacement
needlewheels are smaller?

I haven't replaced impeller yet. I have a spare pump at home, are you saying that the impellars are smaller or the nw's themselves are smaller?

[mr. pluto]

yes the circumference of the needle wheel assembly is smaller,
it is about the size of my OR3700.

the orignial needle wheel on right & or3700 left

[squin]

Originally posted by mr. pluto
yes the circumference of the needle wheel assembly is smaller,
it is about the size of my OR3700.

the orignial needle wheel on right & or3700 left

I have received 2 replacement impellars on 2 occasions (shipping error on the part of the supplier). Both times the new impellars have a smaller diameter for the 2 needle wheels. Running these new impellars drops my wattage and airflow as one might expect. I'm beggining to wonder if the replacement impellars are actually for a OR3700 as opposed to the correct impellar for the OTP3000. In your photo the OR3700 appears to have 3 needle wheels as opposed to 2 on the OTP300. If this correct?

I'm still running my original stock needle wheel. I have modded one of the replacements by removing one wheel completely, and removing half the pins on the remaining. I added 3 layers of Enkamat using fishing line. My airflow jumps from 15 SCFH to 23 SCFH, but the wattage runs a little to high for my comfort at 120+ watts. I hope to receive the correct venturi I had originally ordered along with the replacement impellar on Monday. Once I have a backup venturi I will try the mods outlined by David a couple of posts above on this page. Hopefully that will solve my wattage problem.

[davidabrown66]

Originally posted by squin
I have received 2 replacement impellars on 2 occasions (shipping error on the part of the supplier). Both times the new impellars have a smaller diameter for the 2 needle wheels. Running these new impellars drops my wattage and airflow as one might expect. I'm beggining to wonder if the replacement impellars are actually for a OR3700 as opposed to the correct impellar for the OTP3000. In your photo the OR3700 appears to have 3 needle wheels as opposed to 2 on the OTP300. If this correct?

I'm still running my original stock needle wheel. I have modded one of the replacements by removing one wheel completely, and removing half the pins on the remaining. I added 3 layers of Enkamat using fishing line. My airflow jumps from 15 SCFH to 23 SCFH, but the wattage runs a little to high for my comfort at 120+ watts. I hope to receive the correct venturi I had originally ordered along with the replacement impellar on Monday. Once I have a backup venturi I will try the mods outlined by David a couple of posts above on this page. Hopefully that will solve my wattage problem.

My nw's look like the pump on the right...interesting why you would receive the other ones.

Are you waiting for a venturi for the DNW-200? I'm having a heck of a time tryint to find anyone that has these in stock. Let me know. Thanks!

[squin]

Originally posted by davidabrown66
My nw's look like the pump on the right...interesting why you would receive the other ones.

Are you waiting for a venturi for the DNW-200? I'm having a heck of a time tryint to find anyone that has these in stock. Let me know. Thanks!

My skimmer is the PCI RPS-3000, but I think it is the same as the DNW-200. My original impellar looks like the one on the right as well. The replacement impellars I recieved had the smaller diameter needle wheels.

I ordered a replacement venturi and impellar from Champion Lighting & Supply. They had the parts drop shipped from Pacific Coast Imports (distributor for my skimmer). I received the wrong venturi in addition to the impellar with the smaller diameter needle wheels - twice. The venturi parts I received looked like the venturi for the RPS-2000. Any way I spoke with Jason (very helpful guy) at PCI and I should have the correct part on Monday. I'll let you know if its the correct part. If so, maybe you can order one through Champion.

On another note... Just for giggles I reduced the water flow through the venturi by placing a standard, garden hose washer on the inlet side of my venturi. kroe mentioned reducing water flow earlier, and I wanted to experiment with reducing the water flow when using my mesh modded impellar. The results were positive, 26 SCFH (very steady, no bouncing ball) and 107 Watts. This is a positive for me because I was pulling ~ 25 SCFH and 126 Watts without the reduced water flow. Once I get the replacement venturi I will try the RO tubing mod that you and others have had success with.

Maybe you can try a garden hose washer on your reemed out venturi. It's a very simple mod and its reversible. I just pressed the flexible rubber washer into the inlet of the venturi where it tapers in. I'm hoping it could decrease water flow and increase air flow. Let me know your results if you try.

Still shooting for 25 - 30 SCFH and 65 Watts!