View Full Version : Octopus NW 200 Skimmer

11-06-2007, 08:17 PM
Here is my new skimmer. I will be documenting the modifications researched from the web and how easy they are to complete, even for the DIY challenged. (DKone)

Here it is in the box;

The skimmer comes with a very poor venturi design. The opening is about 1/16" that runs from the opening to the mixing chamber. http://i107.photobucket.com/albums/m308/Co_murfman/Octopus%20mods/IMG_0874.jpg

It has a small plastic nipple on the top of the ventrui casing pressed in. The chamber turns 90* into the opening.

I pulled out the plastic nipple and drilled the venturi hole with a 1/4" drill bit to fit 1/4" OD RO/DI tubing. The hole is drilled all the way through venturi casing to where the water is pulled through.

11-06-2007, 08:18 PM
The new hose is cut at a 45* angle and inserted into the new hole;

Installed hose. If the skimmer is in the sump, no need to seal the tubing, if it is external you will need to put a dab of silicone to seal the ring around the tube.

The venturi is then intalled but I didn't like the way it protruded through the casing and was exposed to the posibility of snails or hermits being sucked into the pump so I installed a strainer and zip tied it to the casing;

11-06-2007, 08:23 PM
The pump comes with a two wheel needlewheel impeller;

I cleaned up the inlet hole with a Dremel and grind stone to make water flow smoother;

I then cut some Enkemat (Thanks Deuce67) wheels, the diameter of the needelwheels;

I then zip tied 3 layers to the needlewheels, some cut off the paddles on the top wheel or remove it so they can add a 4th layer of Enkemat;

The 90* inlet to the skimmer is poorly designed. One end of the 90* has a smaller opening (leaving the pump) and a larger opening going into the skimmer. I used a 5/8" drill bit to open up the 90*, you can go as much as 11/16" but you need to be careful.

11-06-2007, 08:40 PM
The gatevalve modification replaces the vertical tube that is the water outlet. If you chose not to do the mod, you have to adjust the water level in the skimmer by moving the tube up and down. The gate valve allows for a much finer adjustment and you can also direct the retrun flow to where you want in the skimmer.

Here are the PVC fittings I had to purchase to make it work. Since the plumbing is 1.5" and the gate valve was 1.25" I had to buy a bushing and then neck it down to 1.25" for the gate valve side. You could keep the outlet side at 1.25" but I chose to open it back up to 1.5"

I didn't want to buy a whole section of 1 1/4" pipe so I bought two 1 1/4" street 90* fittings and cut the pipe where it meets the 90* turn;

Glue them into the gate valve AFTER you have dry fit everything and know exactly where you are placing the plumbing;

11-06-2007, 08:51 PM
I used a street Y in 1.5" and it attatches to the black drain pipe that came with the skimmer. The black pipe is metric and the pvc is standard so I had to adjust it.

I took a small piece of the pvc and slipped it into the metric piece with a lot of silicon to seal it;

Gate Valve plumbing installed. I had to go over a 12" piece of glass to get it to drain where I wanted. If you place the gate valve lower in the tank, you need to extend the street Y on the right with a riser tube, to keep water from overflowing like the old black, metric tube. It only needs to be as high as the collection cup.

11-06-2007, 08:52 PM
Here is the skimmer installed in the sump;

Here is a pic of the bubble size;

Next modification will be the recirculation mod.

11-06-2007, 09:23 PM
Very cool. Thanks for the documentation.

11-06-2007, 10:28 PM
So how has it been working for you Murf?

11-06-2007, 10:44 PM
Just completed the Gate valve mod today. Have bubbles in the bottom of the neck on the collection cup after a few hours. Without the GV mod, it was pulling more than my EV did.

11-07-2007, 08:35 AM
Cool! What readings are you getting on the air intake?

11-08-2007, 10:04 AM
So here we are, two days after all the mods. I am one that can't leave things well enough alone so even though the skimmer was pulling more skimmate than my EV-180 ever did, I needed to tweek it. I borrowed Deuce's air flow meter and hooked it up. I got a reading of 3-4. Not near enough flow for me so I started making some adjustments.

1st, I cut all the paddles off of the impellers except in a +. I zip tied 4 layers of the Enkemat on it and took a bucket, filled it with fresh water and used it for testing. Less airflow. I then drilled the venturi hole (pic 4 above) to 3/8" and used some 1/4 ID plastic air line to try and get more air in the mixing chamber. The tubing restricted too much flow and the out flow of water was amost non-existant. I sealed the hole back up and drilled for the RO tubing and reinstalled that.

Pic of the top layer of paddles cut off. I just used a pair of wire cutters to remove them;

I cut a 2" piece of IO salt bucket, using a hole saw (Deuce's suggestion) and drilled the center hole out to 1/2". I then drilled a lot of small holes around the disc and placed the center hole over the impeller center. I ziptied it to the +. I then put on the 4 layers of Enkemat and ziptied them to the disc. I reinstalled it and here are the results 18 hours later;

11-08-2007, 10:29 AM
very cool

11-08-2007, 01:03 PM
I cant really tell from the pic, but it looks like you can close the GV just a bit more.

12-21-2007, 10:53 PM

How do you like this skimmer?


12-23-2007, 10:34 AM
Hey Marty. I like the skimmer, puts out a lot of bubbles. Just not as Happy with the amount of skimmate I was expecting. I clean the collection cup 2x a week and pull gobs of gunk from the neck of the tower but not too much makes it into the collection cup. I have it set to skim wet too. If you are thinking of getting one, I would run it without modifications for at least a month so you get an idea of how it pulls and then start modding it. For the price, you really can't beat it.

12-23-2007, 10:39 AM
Thanks Paul. I have been looking at this one for my 125G. I think I will order me one.


12-23-2007, 10:41 AM
Let me know and I will link you up to the modification threads I know about. Who are you getting it from?

12-23-2007, 10:55 AM
Marine Solutions. I have to get all my things before I set the tank up. I have to have the takn drilled or go with over flows? I want to have all the stuff here before I start set up.


12-23-2007, 01:30 PM
Just give it time.......mine took a long time (months) before I got it tweaked just right so it produced nothing but really dark smelly skimmate.
Heres a shot with the cup off...........nice and smooth tons of fine bubbles, no turbulence I could almost take a sip ;)

12-23-2007, 02:04 PM
Looks and smells like beer to me:yesnod:

12-23-2007, 03:55 PM
Scratch & Sniff ;)

12-28-2007, 01:16 PM

on a sidenote: im thinking of getting their hob skimmer-think its worth a wurl?

12-30-2007, 08:54 AM
well i ordered it this morn, will tell everyone how it is when i get it

01-10-2008, 04:57 PM
Took two months to break in. Pulling about 1/2-3/4 cup of dark brown skimmate a day now.

01-10-2008, 09:40 PM
i took mine down, way to many bubbles. am i missing a sponge or floss for the middle?

01-10-2008, 09:42 PM
bubbles should be about 1/3 of the way up the collection chamber. Sponges go on the output tube to keep water from crashing back into the sump.

01-11-2008, 12:03 AM
Grats on getting that Skimmer working well Murf !

Warm Regards,

01-11-2008, 06:48 AM
i never got sponges

04-17-2008, 10:02 PM
Hey Paul, Have you started your recirc mod Yet?? Just curious how it was coming along..

04-17-2008, 10:30 PM
Hey Paul, Have you started your recirc mod Yet?? Just curious how it was coming along..

Have the uni seals so I am getting all the small parts to start doing it. Prolly do it next weekend. Anyone have an 1 3/4" hole saw?

04-18-2008, 11:37 AM
OK, I need some input here. I am making my skimmer into a Recirculating skimmer and as I was making a list and checking it twice (or a hundred times), I came upon this idea. Instead of having the return from the tank dump into the side of the skimmer, I was thinking of having a Tee fitting on the inlet side, before the venturi, and having the water enter there. The water coming from the tank would be mixing with skimmer water and being chopped before it is shot back into the skimmer.

As I am typing this, detritus would be an issue as the water is not filtered before it hits the meshmod. What about the Tee being on the return side of the pump so it mixes with the chopped water as it enters the skimmer? Would this work well? If not, it would have to be in the side of the skimmer.

04-18-2008, 11:45 AM
I think you are going to choke out the skimmer pump by doing that.

04-18-2008, 11:49 AM
I think you are going to choke out the skimmer pump by doing that.

What if I use a bigger pump?

04-18-2008, 12:12 PM
Then you will choke it out even more. Dont feed the skimmer pump. Why not just drill for an intake?

04-18-2008, 02:12 PM
I am, I was just being dangerous and brainstorming.

04-18-2008, 10:02 PM
Well it is done. I had to make some serious enginering to get it to flow from the overflow into the skimmer.

1/4" barbed hose fitting is the new venturi;

Cut 45* making a pointed tip. This gets installed with the V notch facing the meshmod;

Drilled a 5/16" hole 3rd from the last thread to install the barb fitting. Superglued to the housing;

Side view of the new venturi;

Had a 3/4" Union so I used it with an adapter to give some space;

One end has a 3/4" thread that goes in the 90* fitting and the other slips on to the 1" PVC.

04-18-2008, 11:14 PM
Pump with the new 90* fitting and venturi;

A threaded 90* wont work trying to thread it onto the Octopus pump. A guy on RC got the slip fitting to work using teflon tape and twisting it on. I heated the male threads and forced the 90* fitting on to it, cutting new threads. I also used the black PVC glue to hold it in place. I drilled two small holes 180* apart and put a zip tie through. I hate being awakend at 3am to a pump fountaining in my stand.

The grey piece is the old venturi and output. I ground down the inside of the 1" PVC so that it would fit over top of this, tightly.

This is the old inlet on the skimmer, I had to cut it off carefully, using a Dremel, so that I could drill it out for the 1" uniseal;

Two 1 3/4" holes ready for the uniseals;

Two 1" Uniseals in place;

Pump installed;

04-18-2008, 11:31 PM
In order to get water into the skimmer and not have to run a feed pump, I decided to feed directly from the overflow. Since they don't sell a 1 1/4" Y I had to pull a Timbo and make one from a T fitting that is 1 1/4 to 1/2" on one of the outlets;


I had to make diverter to direct water into the 1/2" barb;

I cut a 3/4" piece of PVC in half and sanded it down to fit in the 1 1/4" Tee;


04-18-2008, 11:36 PM
Reserved for the drain line and skimmate shots.

04-18-2008, 11:55 PM
I can't wait to see how it works. That looked like a lot of work.

04-19-2008, 07:02 AM
At least nobody can say that Paul never tries to improve his system, LOL
With all the man hours involved you and Tim have more money in your systems than I have in my 600 ;)

04-19-2008, 07:55 AM
Any way you can put the 90 on the pump input and a straight shot out on the output? Other wise, looking good!

04-19-2008, 09:04 AM
Any way you can put the 90 on the pump input and a straight shot out on the output? Other wise, looking good!

I thought about that but the weight of the pump would be putting pressure right on the uniseals.

04-19-2008, 09:08 AM
Pump is not that heavy is it?

04-19-2008, 09:14 AM
It is a pretty big pump, I'd say it weight at least 4lbs. I am just leary of busting the plastic like what happend on my Lifereef skimmer.

04-19-2008, 09:16 AM
Who cares if you were to get a minor seepage, its only a recirculating pump right? Besides those uniseals can take much more than that from what I've seen. Russ is right, putting a 90 directly on the output of any pump is going to cut the flow rate down quite a bit.


04-19-2008, 09:17 AM
4 lb pump? holy smokes what does that thing put out 3500 gph?

04-19-2008, 09:24 AM
I am open to suggestions!!!! Anything to make it better. I might mess with it next weekend. I want to see what kind of junk I pull.

If I go with the 90 on the inlet, I am going to have to replace the outlet that threads into the pump. Who in town sells metric plumbing supplies?

Green Wrasse
04-19-2008, 09:34 AM
Maybe you'll win big in Cripple Creek and can roll like Chris with a B.K.:christof:
Good luck and happy Birthday.

04-19-2008, 09:34 AM
Thanks Russ!

04-19-2008, 09:36 AM
Oh yeah happy B-day, sorry you have to be getting so old, it makes the rest of us feel better though ;)

04-19-2008, 09:38 AM
LOL it was actually Monday. As my #1 daughter reminded me, I am only 3 years away from 50. Thanks kiddo.

04-19-2008, 09:42 AM
Here is the Octopus receric 200;


04-19-2008, 10:21 AM
When I first got my Orca, the 90 was on the output. I reconfigured it to have the 90 on the input and gained 5-6 lpm of air.

04-19-2008, 10:26 AM
Well, I just discovered that I have too much turbulance in the chamber. The diffuser T blew out of the 1" pipe so I am going to have to get a 1" NPT to 1/2" threaded so I can put on a T to direct the flow off to the sides instead of straight out. (the diffuser T I used was the stock one and I siliconed it inside the 1" PVC, that didn't work)

My only concern is when I neck down from 1" to 1/2", it is going to increase the pressure at the outlet. What do you think about just using a 1" T on the outlet?

04-19-2008, 10:35 AM
Lol! 1 sent PM from me and the whole thing is gonna change lol! Hopefully the new pump will work!

04-22-2008, 11:02 AM
Here is the drain from the overflow to the skimmer;


Don't worry ,the black splice will go away when I get some more 1/2" hose ;-)

Bubbles in the chamber;

Here is about 24 hours of skimmate;

The skimmer density, I think it is a little too wet;

About 12 hours worth with the 90* return fitting removed so there is less back pressure on the return;