Octopus Skimmer Mods

[impur]

I got water in it from the first test. So it was off anyway. I tested again today after it was dry and was getting 17l/m

[JCTewks]

impur, is that with the meter vertical?

[djc1026]

For all you Octopus modders, I'm looking at getting the 200 for a 150 I will be setting up. If you had to recommend one mod for the DNW 200, what would it be?

Dave

[outy]

mesh, but you want a few more simple mods. mesh without venturi mod isnt really worth doing.

[wharfrat48]

I have had my NW200 running for a week now and I am getting absolutly zero skimmate. I have the water level tube all the way up to the bottom of the collection cup and everthing appears to be working fine but the bubbles keep breaking in the neck. I rinsed the unit in RO/DI before I put in so I'm not sure what could be wrong. I have a ASM G1 running along side and it is working fine. I was planning on doing the mesh and venturi mods but I dont want to mess with anything if I end up needing to return the unit. Any suggestions?

Thanks

[impur]

Originally posted by JCTewks
impur, is that with the meter vertical?

Yep, and its really loud. But it was my first attempt, gonna try some things and maybe a new venturi on my otp3000.

[deuce6371]

After 6 months or so I finally had the time to mod my Reef Octopus TDNW-300.



I have to say, I had my doubts but it was extremely easy and made a big improvement.

Here is my starting air draw in SCFH.



This model has threee octo 2000 pumps. The impellars have two rows of blades I removed the first. I did leave a small part of the first row on just to help hold the mesh in place. Having finished it now I think I could of removed it.



I then put three layers of enkemat on with small cable ties. I made sure to have the ties equal distance apart (three blades between each tie), that way they are somewhat balanced. I also made sure the clamp part of the tie was tucked inside the mesh so it would not drag the impellar housing when it ran. I then trimmed the mesh so it was even with the end of each blade and made sure none were sticking out the top or bottom that would drag.



After a few trial and errors getting the pumps attached and taking them off agian to trim the mesh back I had success. I was not expecting a huge gain but it was visibly noteable in the body of the skimmer that the air had been increased. It went from about 12 SCFH to 21 SCFH.



Like I said this was easy to do and I really had been putting it off because I was afraid of screwing something up. I just followed the directions that everyone had been leaving in this post and it went off without a hitch. I think it took me about 1.5 hours to do all three. Most of the time was spent on the first just figuring some stuff out, after that it went fast.

I am already noticing a huge difference in the first hour of running it. I opened up the drain valve quite a bit to ensure it does not empty out the sump. After a couple days I will make some final adjustments and post the results and some pics.

For anyone putting this mod off, do yourself and your tank a favor and get it done ASAP. This was definitely not hard and made a major improvement. Thanks to everyone before me that took the time to post their work.

[victor90]

deuce6371
Hi Can you post pics of the skimmer in action after the mod

[deuce6371]

Originally posted by victor90
deuce6371
Hi Can you post pics of the skimmer in action after the mod

Actually the first pic is the skimmer directly after the mod. I do not have any before the mod. I will post another after a day or so to give time to break in.

JB

[barjam]

Anyone try to mesh the 1000 pump? I think it is too small. I used to layers of mesh heat gunned down as thing as I could and it still came pretty closing to rubbing.

A month after I got it to work a small snail shell got sucked into the assembly and locked up the pump. Locked up pump = melted and shorted out.

Edit: Well, looks like people have modded the 1000. I give up, I don't want another locked up pump.

[davidabrown66]

Originally posted by wharfrat48
I have had my NW200 running for a week now and I am getting absolutly zero skimmate. I have the water level tube all the way up to the bottom of the collection cup and everthing appears to be working fine but the bubbles keep breaking in the neck. I rinsed the unit in RO/DI before I put in so I'm not sure what could be wrong. I have a ASM G1 running along side and it is working fine. I was planning on doing the mesh and venturi mods but I dont want to mess with anything if I end up needing to return the unit. Any suggestions?

Thanks

The Octopus won't produce much of anything stock. You're probably around 270 LPH of air stock. You need to do the mesh and the venturi mods at least to get it to perform. Also, before you do the mods I would suggest rinsing it in white vinegar to get the factory oils off. You can also run it with vinegar which will also remove the factory oils from your new OTP-3000 as well.

Also, if you decide to do the venturi and mesh, you'll need an air meter:

http://www.dwyer-inst.com/htdocs/flow/SeriesRMPrice.cfm

I would buy the RMA-22, and then buy a Kill-o-watt meter (google it to see where to buy) to measure what's happening to your wattage. This is the only way to truly measure what mods are having what effect. If you don't plan on doing any mods, I'd return it.

If you do plan on doing the mods, I'd also suggest buying another OTP-3000 pump and if you can find them, another venturi and/or make your own.

I'd also reread the previous pages starting with page one before the post split the first time if you have'nt, to see what others have done and to see what works best, and pictures of how to do it. Even then, you'll need to do the mods like the mesh over and over again to really get good at it so it's balanced and even.

Also, you'll want the PF4 (Enkamat) for the mesh. You can buy that on ebay for about 5$

The main thing is, that these skimmers our lousy performers right out of the box, and can take a couple of weeks before the factory oils in the acrylic come off. You can try soaking it or running it with white vinegar to decrease that time frame for the oils to dissapate. Even then, you're only getting about 25% of the performance when compared to what the mods will give you.

Hope that at least guides you to your decision.

-David

[porthios]

so is there a clear winner on the venturi mod yet? i've done the mesh mod but was waiting to do the venturi til it got hashed out a bit..

[wharfrat48]

I was planning on doing the venturi and mesh mod, but I was expecting at least some skimmate from the stock model. I have read all of this thread, and like most, there is conflicting info among the various posts (one being the stock models work great, doing mods even better). I'm guessing the "factory oils" must be the problem so I'll try a vinegar rinse. As for the 2 mods I was planning on doing-- is there a concensus yet on the best way to do them (see pothios' question) Right now I am planning on drilling out the venturi (both ends of the 90 degree) and using 1/4" ro/di tubing. For the mesh mod-- I was going to remove 2 of the three needlewheels and add 2 layers of P4 with fishing line---does this sound right?

Thanks for your help

[davidabrown66]

Originally posted by porthios
so is there a clear winner on the venturi mod yet? i've done the mesh mod but was waiting to do the venturi til it got hashed out a bit..

Well, depends on which skimmer (nw-200 or dnw-200). The diy venturi is much easier for the nw-200 since it sits in water, and you don't have to match up the recirc plumbing to the skimmer body just right so it doesn't leak, and deal with the metric fitting conversion.

I've been able to just recently get about 850 LPH from my stock venturi. What I didn't anticipate was the redesign of the OTP-3000 to use a smaller nw impeller so I had to cut the mesh to a larger diameter. I don't know if there's a clear winning design, but I would follow and maybe even search for these users' posts to see the most up to date info on the Octopus recirculating mods:

JCTewks
Outy
Impur

There are many others here who have contributed to the success of this thread and others just like it, so without them we would'nt have come as far, but the new OTP-3000 just doesn't perform the same way as even 3 months ago, and it's only been in the last few months that there have been new pioneers working to make the dnw-200 and 250 an even better skimmer, because there are additional challenges to modding a recirc skimmer.

It's still a good pump and skimmer if you do the mods...with lots of head room for mod improvements, but gone are the days of 1200+ LPH IMHO. It is an energy hog, and it can add heat to your water if you're not carefull with your mods.

[victor90]

how is it if i just do the mesh mod without the venturi mod
thanks

[porthios]

i went from ~7 to 14-15scfh with just the mesh mod on a newer version of the pump.

[davidabrown66]

Originally posted by victor90
how is it if i just do the mesh mod without the venturi mod
thanks

You'll see some improvement, but it's really not worth it unless you at least bore out the internal area of the stock nipple to match that of RO line I think it's 1/8" since the OD of RO line is 1/4", and also drill out the other side of the venturi where air enters the waterway to the same diameter, but retain the 90 degree corner of the venturi. Just make sure you clear the shavings completely by blowing in it, and be carefull drilling out the ID of the nipple so you don't go all the way through to the waterway. From that alone including mesh you should double your airflow to around 550-600 LPH. IMO, this is too low for this skimmer to be usefull at all long term on a full SPS system unless you can make up in water changes what the skimmer is leaving behind that is.

I was battling with 600 LPH with mine for a while, and then after several tries I got the magic combination for me (even though others have had better success). I'm now at 900 LPH, and the difference in what comes out makes me want to shoot for 1200 LPH which would be about max for an 8" x 30" skimmer, and may even be too much if I can't control the turbulance.

I hope that helps,

-David

[porthios]

tbh, i'm pretty pleased with the nw-200's performance at 15scfh.

[impur]

Originally posted by wharfrat48
I have had my NW200 running for a week now and I am getting absolutly zero skimmate. I have the water level tube all the way up to the bottom of the collection cup and everthing appears to be working fine but the bubbles keep breaking in the neck. I rinsed the unit in RO/DI before I put in so I'm not sure what could be wrong. I have a ASM G1 running along side and it is working fine. I was planning on doing the mesh and venturi mods but I dont want to mess with anything if I end up needing to return the unit. Any suggestions?

Thanks

When i ran mine right out of the box i noticed the venturi where it makes that elbow in the grey fitting would clog with salt creep. Just another thing to check, try running some RO water down the airline.

[davidabrown66]

Originally posted by wharfrat48
I was planning on doing the venturi and mesh mod, but I was expecting at least some skimmate from the stock model. I have read all of this thread, and like most, there is conflicting info among the various posts (one being the stock models work great, doing mods even better). I'm guessing the "factory oils" must be the problem so I'll try a vinegar rinse. As for the 2 mods I was planning on doing-- is there a concensus yet on the best way to do them (see pothios' question) Right now I am planning on drilling out the venturi (both ends of the 90 degree) and using 1/4" ro/di tubing. For the mesh mod-- I was going to remove 2 of the three needlewheels and add 2 layers of P4 with fishing line---does this sound right?

Thanks for your help

Sounds like your impeller is of the older type (3 nw rows instead of 2). So, this might be an older style of OTP-3000 which would work in your favor. The way to tell is if your nw diameter is greater than 2" then you have the older style. If you nw is I think 1 7/8" then you have the newer style of nw.

The conflicting posts are from older posts before the OTP-3000 was redesigned. At least the NW was redesigned twice (one with 3 rows of nw's and the other with 2 shorter nw's). I don't know off hand if the 3 row nw's are still of the larger diameter make. Anyway, with the new nw design you have to make the mesh larger than the diameter of the nw's so they almost touch the volute rim, but not quite. I can practically stick my finger in between where the nw ends and the volute rim is with mine.

I like fishing line the best, and I use 4 layers, but I would start with 3 and add the fourth while taking air draw measurements and wattage usage to see what it actually is doing for you.

And, yes you only need one layer of nw for the PF4 to attach to.

I don't know what RO line will do for you. If you drill out the airway to 1/4 for RO line only to insert RO line that will decrease the ID back to 1/8". Why not just drill it to 1/8"? Besides, I don't think you'll be able to retain the 90 in the airway if you drill it out to 1/4" but not sure. If I were to do it again, I would drill out the nipple completely with a 3/8" drill bit, and not go all the way through as i did. I would retain the original 90 while opening it up to 1/8". Then I'd insert a barb with 3/8" threaded end with a 1/8 in ID. Screw that in with some aquarium sealant making sure the 90 degree turn has'nt been plugged, and that's it. You'd drill straight into where the nipple used to be and at the same angle as the nipple, but only as deep as the original airway (so not all the way through to the waterway). Then, drill out the airway on the other end of the venturi with as large of a drill bit you can go without reaming it out to the point where it opens up the airway to the waterway prematurely...so like 1/8".

I hope that makes sense.

[davidabrown66]

Originally posted by porthios
tbh, i'm pretty pleased with the nw-200's performance at 15scfh.

If you're pulling anything out at 15 SCFH (425 LPH), then you probably have an organic build up in your water of some sort IMO. You would absolutely fall over if you saw what would come out of your skimmer if it were at 30+ SCFH. It would the color of coffee, and have the smell of death.

[porthios]

i didn't mean it couldn't get better. just that i'm pleased with it. the fact that it's pulling anything at all out of ~100gals with one 1" osc clown fish makes me happy. perhaps i'm easily pleased..

that said, you can obviously have too much air and or water before you run into turbulence probs. early in the thread rich mentioned 20-25scfh as 'about all this body/neck can take'. any reason you think 30+ is a better number?

[davidabrown66]

Originally posted by porthios
i didn't mean it couldn't get better. just that i'm pleased with it. the fact that it's pulling anything at all out of ~100gals with one 1" osc clown fish makes me happy. perhaps i'm easily pleased..

that said, you can obviously have too much air and or water before you run into turbulence probs. early in the thread rich mentioned 20-25scfh as 'about all this body/neck can take'. any reason you think 30+ is a better number?

Sorry if I was getting kirt in my replies.
Yep air/water ratio is important, and I think (without going through all of the posts again) he was talking about the nw-150, because that has a 5.85" neck which would be about right, but I base the airdraw numbers on what a Euroreef produces. A RC180 is 8x24 skimmer and has a 960 LPH air draw, and their RC250 draws slightly less at 900 LPH, and is the same size as the DNW-200 (8x30). So, I suppose the extra 6" of water height adds enough back pressure on the pump that it in turn cuts down on the air/water, b/c it's the same pump, just a taller skimmer.

Most people who have done all the mods to the OTP-3000 are getting 30+ SCFH, and I know of at least 3 others who have gotten 40+ SCFH out an OTP-3000 and had to add an air valve to the airline which cut their LPH, but in turn created microscopic bubble sizes. That's what I'm hoping to achieve, is an undestinquishable and stable bubble size with the least amount of water movement and wattage used.

So far, I've done the mods and I'm getting about 30-32 SCFH (900 LPH) with enough room for additional dry foam, and with those numbers I think I've got a skimmer that is equal to the Euroreef RC250 that I could've bought for many hundred of dollars more, and now that I see what can be pulled out of my tank at 900 LPH vs 600...I want to try 1200 LPH to then be able adjust it with an air valve for the best extraction of organics.

I think the 42 SCFH would be about max for my setup, and probably more like 35-40 realistically for the best result with an airline valve for the best bubble size, but that's just my opinion. I like to tinker and see what happens. Sorry again, if I was coming across to blunt, I'm still at work and trying to write these while looking like I'm actually working.

[porthios]

'Sorry if I was getting kirt in my replies.'

not at all. nor did i mean to..

it would be very interesting to see video of different flow rates through the skimmer. i know you've done several versions of the mods. any chance you have a camcorder?

[deuce6371]

anyone know where I can order a shaft only for a OTP 2000 impellar. Dropped mine and watched it shatter.