Octopus Skimmer Mods

[hounddog01]

Originally posted by kroe
Here's a thread with my modded NW-200 pulling 45 scfh (pics included): http://reefcentral.com/forums/showth...eadid=1109423.

I posted it as a different thread since this one is easy to get lost in.

-Ken

Is it just me or are the pictures missing?

[kroe]

Yahoo photo hosting sucks... I uploaded them to RC, so now the pics are there.

[reefez]

You know the 3000 is a great skimmer when you do a 40 gal. water change on a 125gal. tank and an hour later it is pulling scum out again. The mods we're a big success and I am very happy with the 3000.
One question concerning the air adjustment. I have a needle valve hooked onto the venturi line and am wondering where the ideal setting is on other skimmers. It seems when it is barley open just enough for it to start sucking air I get a nice dry foam with very tinny bubbles in the neck. When I open the air a little more the foam get's more wet with bigger bubbles. Is this the norm? I have no idea how much air it is pulling, but it is performing well either way. Just wondering where people have their air set? I swear I am drawing more air by haveing the needle almost all the way closed. Strange how that works.

[kroe]

When you close the air valve your air intake goes down but your water intake goes up. This will seem like more flow coming out of the pump sometimes, but with an air meter you'll see the air intake drop. In addition your water/air ratio will rise increasing turbulence big time. In general you are better off with the air valve more open.

If the foam is too wet with it wide open, drop the level of water in the skimmer.

[hounddog01]

You almost need an air meter to determine how far to open or close it. I would say run it open and adjust the water in the skimmer. This is your best bet unless you have an air meter. Then adjust it until you have the best draw and adjust the water level acordingly.

[davidabrown66]

Ok, I finally got through reading the first forty pages and teh last 17 pages of the split thread, but I still need some advice from people who have modded their DNW-200/RPS-3000. I'm hesitant about modding this, and it seems like most of the modding done has been on other models so I don't want to follow the same directions for modding this b/c they're different enough.

So far, this is what I've done:

I've added 2 layers of Enkmat on my stock impeller, I've reamed out both sides of the venturi, and kept the original (long) venturi valve intact. It still has a 90 degree bend, but it now has a 1/4" ID diameter which is the same ID of RO tubing, unless we're talking 3/8" I guess. I saw an increase in bubble density when I added the 2nd layer, and reamed out the venturi, but that seemed to only last an hour or two. So, I'm not sure if a larger hole is the way to go, b/c it seems like there's a ratio that needs to be maintained.

I'm still not getting much foam, in fact my EV-180 took out a 1/2 cup daily, and this has only produced that much in 1 month. I know there's some break-in time, and I didn't prewash with vinegar, but I know there's stuff to skim b/c my nitrate shot up to almost 2.0!

I've only had it a month or so, and I have fine micro bubbles down to where the water re-enters the recirc pump. The water level is at the top of the 8" opening just before it tapers to the union. The foam collected is about 1/4" on top of that. It's been better, but I just added 150 ft total of plumbing to move my sump to the garage, so I know that'll kick it off for awhile, but even before I moved it, I was only getting about what I stated before.

Here are some questions I have:

1) I'd like to test a larger venturi hole, and I'd like to test this on a 1" pvc fitting with a 3/8" OD hole, but not sure if I should drill at an angle or keep the 90 deg turn in the venturi hole, and how to reconnect the pvc fittings again to the pump and body. Anyone done this on a recirc that can give me exact drilling sizes, pvc fittings to buy? I have threaded JG fittings for 3/8" OD if that helps.

2) I'm leary of trying to do any work on the volute or the pump housing to increase diameter, b/c I know it's easy to over heat the plastic, and I only have a drill. I have a 5/8" spade bit and a 3/4" sanding drum (as recommended by another DIY'r), but how do you ream it out if you can't put the tip of the bit on anything?

3) Do I need to give this some more gear time?

4) Is it recommended I buy another pump and/or Kilawatt meter before doing any other mods?

5) Is there another pump that works nearly as well as this one, but doesn't need any modifying?

6) I don't know what my air draw is yet. Is there someone local in the Puget Sound area that sells Dwyer meters? I'm looking to borrow or buy a RMA-7 (5-50) to use.

7)Do I need to ream out these parts I stated above in order to see a benefit in a larger venturi long term?

8) Am I missing something?

I'd like to hear the air being drawn into the ventui tube like a jet engine like someone else wrote, but I'm affraid I have to get my ear pretty close just to hear a girgly noise.

Any help would be much appreciated. If you're local and can lend a hand on the finer points, I'll pay for beer and pizza. Oh, did I mention I use to be a bartender

[impur]

I bet you are getting salt creep buildup at that elbow. Clean out the venturi so you know its clean and let it run for a few hours until you see the decrease in performance, then try running some RO water down the venturi airline and see if it goes back to normal performance.

Don't worry about the airline for the venturi being too large, you can always reduce the air coming in with a valve.

[MgCl2TiCl4]

I have the Pacific Coast 1000 recirculation unit and made the Enkamat mod. However, the skimmer overflowed uncontrollably (3 gallons pouring out within 1 hour) after the mod even with the outlet valve wide open.

I fixed the problem by using an air valve at the silencer to restrict air. Now working perfectly and stable. I think that the Enkamat mod may not be suitable for all environments.

[squin]

Here is my experience with an RPS-3000 that I have been running about 3 weeks. I'm new to this forum and I have read all the posts. There is a wealth of information, some helpful, some confusing.

1) I ran the skimmer in a vinegar bath for about 24 hrs, and installed the skimmer. The only mod I made was to gap the washer so it did not block the 90 degree opening. Out of the box I was getting about 7 SCFH with a Dwyer meter and running at about 70 watts on a Kill-A-Watt. I ran this setup for about a week and was getting a wet, tea green skimmate.

2) I bored the air intake for the venturi slightly with an 11/64th bit drilling straight through and opening up the 90 degree hole. I'm afraid to go much bigger because I don't want to crack the nipple. I added 3 layers of Enkamat to the stock 2 wheel impeller securing the mat with fishing line. This resulted in an increase in air flow to 15 SCFH, but the wattage jumped to 112 watts! The pump is hard to start and sometimes requires that I blow into the air line or the pump trips on overload. I get a much darker skimmate now, running the water line at the base of the neck.

I ordered a spare needle wheel and venturi, but received the wrong venturi. I'm still waiting for the correct part. I'm afraid to mod my original venturi further without a replacement on hand.

My next mod will be to break off a row of needles and add 3 or 4 layers of Enkamat. I will also mod the venturi by boring it out, remove the nipple, and inserting the 1/4" RO tubing into the flow stream. I would like to use a 1/4" JG fitting but it looks to be a tight fit on this short venturi.

My question is does anyone have a specific diameter for boring the venturi? Were you able to tap and install a JG fitting on the stock venturi? What were the resulting SCFH and wattage readings? Is it possible to get to around 30 SCFH and keep the wattage down to around the rated 65 Watts? I run this skimmer external to the sump so I need to be sure any mods don't leak.

Any specifics you have would be greatly appreciated. Thanks for all the info!

[reefez]

Here is my experience with an RPS-3000 that I have been running about 3 weeks. I'm new to this forum and I have read all the posts. There is a wealth of information, some helpful, some confusing.

I have been running my octopus 3000 for a little over a week now. I started out right off with a 5 hour vinegar bath and a mod to the impeller with 4 layers of gutter guard. I also reamed out the venturi nipple a little without breaking it off in fear.
After a couple days I still wasen't satisified with the skimmers performance so I read deeper in the thread. I ended up just snapping the nipple off that the venturi plugs into and drilled it out with a 1/4 in. bit straight down without worrieing about the 90 degree hole. I just inserted the R/O tube in the hole and super glued it in. The next thing I did was remove the gutter guard material and put a 1/4 in. thick piece of 3M Scouring pad on the impeller with 4 small zip ties to hold it on. Also I foregot to mention I used wire cutters and removed the top row of needle wheels before I even gave it the vinegar bath. Next I used the 5/8 in. spade to ream out the intake hole on the pump. I was pretty worried about doing this knowing darn well if I messed it up I would be without a skimmer untill I could get a replacement part. But I went ahead and it worked fine.
Next I used a sanding drum attached to my drill to round off the edges of the valute on the output.
After doing these mods it really has been more of the skimmer that I hoped it would be. I have no air meter so I have no idea what it is pulling or how many watts it is sucking. But I do know it is doing better then it was with the gutter guard and a modified venturi. Hope this helped.

[davidabrown66]

Originally posted by reefez
I have been running my octopus 3000 for a little over a week now. I started out right off with a 5 hour vinegar bath and a mod to the impeller with 4 layers of gutter guard. I also reamed out the venturi nipple a little without breaking it off in fear.
After a couple days I still wasen't satisified with the skimmers performance so I read deeper in the thread. I ended up just snapping the nipple off that the venturi plugs into and drilled it out with a 1/4 in. bit straight down without worrieing about the 90 degree hole. I just inserted the R/O tube in the hole and super glued it in. The next thing I did was remove the gutter guard material and put a 1/4 in. thick piece of 3M Scouring pad on the impeller with 4 small zip ties to hold it on. Also I foregot to mention I used wire cutters and removed the top row of needle wheels before I even gave it the vinegar bath. Next I used the 5/8 in. spade to ream out the intake hole on the pump. I was pretty worried about doing this knowing darn well if I messed it up I would be without a skimmer untill I could get a replacement part. But I went ahead and it worked fine.
Next I used a sanding drum attached to my drill to round off the edges of the valute on the output.
After doing these mods it really has been more of the skimmer that I hoped it would be. I have no air meter so I have no idea what it is pulling or how many watts it is sucking. But I do know it is doing better then it was with the gutter guard and a modified venturi. Hope this helped.

I'm also new to this forum, but have actively read all the posts on this subject. I have a couple of questions if you don't mind?

1) How did you ream out the pump input with a 5/8" spade bit without the center of the bit boring into something at the same time? It seem like the bit would be all over the place. I have a drill, a spade bit, and a vise, but not sure if I would need a drill press to do this mod.

2) Do you run this skimmer externally? I have to be concerned with leaks when modifying the venturi, and not sure if super glue would suffice.

Thanks for your help,

-David

[reefez]

I just held it in my hand and used a brand new spade and went very slowly. It was not the smartest way to do it but I had no vice or drill press. Mine is external and when the pump to the skimmer is turned off I have no leaks around the venturi.

[davidabrown66]

Good to know, thanks. I decided to go and get some different types of grinding bits for my drill, and see what I can do.

thanks again for the info.

[192clark]

I dropped the pin that holds the impeller in place and it broke. Would any one know where I could get another?

[ThaNgBOm321]

well i got my rps-3000 about 2 weeks ago.. ( got it 2nd hand) dont know if he moded it before but i enlaged the pipes with a sharp scissor .. just use one side of it and insert it into the pip.. the twist and you will start scraping.. it worked really good for me.. then the dremal and wood carving but... i smoothed out everything i could on the pips and pump.. took a 12'' chief knife and slid it between the NW ( i only had 2 rows... dont know if this the regular or not) then a slight twist.. work your way around and she will come off.. ( now i have a extra one in case the other break off ) next i grab the mesh i had on hand ( some green mesh filter i got from the lfs in jersy.. ) cut a peice out added 1 layer of GG ( to help keep her in one peice if it happend to start falling apart..) and tied her down via fishline to the NW that i left on .... then i drilled out the venturi that was on there .. and added 3/8 clear tubing.. pluged her in... clank clank clank.. so i blow in the airline... next thing you know SHE's ALIVE!!!!! friggin suck air like crazy!!! dont know how much air she pull or how much watts she use but she can skim some.. imma mess with her a little more and see what i can do...

YzGYz

[squin]

Originally posted by 192clark
I dropped the pin that holds the impeller in place and it broke. Would any one know where I could get another?

I ordered a replacement impeller from Champion Supply.

http://www.championlighting.com/home.php

[192clark]

squin: did the new impeller come with the ceramic pin that holds it in place? My impeller is fine I just need the pin.

[reefez]

where on their page do you go to order the replacement parts?

[192clark]

reefez: I used their search function for impeller and they came up. No shaft for my pump!

[squin]

Originally posted by 192clark
reefez: I used their search function for impeller and they came up. No shaft for my pump!

They don't post the parts for the RPS-3000 on the site. You can give them a call and they can place an order for you. The parts will be drop shipped from the distributor (PCI).

I don't know if the sell just the ceramic shaft, but a shaft and the nececessary grommets and bushings do come with the impeller.

[192clark]

thanks for the help

[davidabrown66]

I just ordered a spare venturi, so now I can snap that nipple off and drill through the new venturi without worry. I want to see what my current air is compared with the stock one arriving to see if reaming out the venturi did anything.

I should receive it tomorrow, and my Dwyer meter will be here next week (it took them 3 days to process the order ).

Anyway, I should have air readings before and after venturi mod for DNW-200 with original impeller and with 2 layers of Enkamat plus gasket mod.

I'm going to wait on any volute and pump grinding to see what that change will do separately.

[davidabrown66]

No salt creep yet, but I did notice a big change in foam production when I added a filter sock to the output of the skimmer so no bubbles are returning to the skimmer. Now, I'm getting very light tea green skim.

Originally posted by impur
I bet you are getting salt creep buildup at that elbow. Clean out the venturi so you know its clean and let it run for a few hours until you see the decrease in performance, then try running some RO water down the venturi airline and see if it goes back to normal performance.

Don't worry about the airline for the venturi being too large, you can always reduce the air coming in with a valve.

[sickman]

Originally posted by davidabrown66
No salt creep yet, but I did notice a big change in foam production when I added a filter sock to the output of the skimmer so no bubbles are returning to the skimmer. Now, I'm getting very light tea green skim.

that's cause you simply slow the output of the skimmer having the same effect as holding more water in the skimmer via the ball valve/gate valve settings.

[davidabrown66]

Actually, the output flows freely into the sock from above water level without any back pressure, and the return pump is next to the filter sock, so now there are no bubbles going back in to the skimmer. I think that bubbles going into the pump can impede overall performance. I've seen this on my other skimmer, but never made the same connection until now. My foam has increased from only getting 1/4" of foam just above the water level just before the taper to the union, to up the neck and into the cup.

I should have my skimmer hooked up to my overflow soon so I can just skim the best stuff soon.

Originally posted by sickman
that's cause you simply slow the output of the skimmer having the same effect as holding more water in the skimmer via the ball valve/gate valve settings.