Octopus Skimmer Mods

[kroe]

I don't know how you are getting such high wattage... only way I can see is leaving needle wheels intact or having the mesh rub on the volute. I never had wattage anywhere near that and had around 25 scfh before modding the outlet of my pump. I have since replaced the outlet of the pump by drilling out the stock fitting and replaceing it with 1" pvc (epoxied in). With the mesh I am pulling 45+ scfh @ around 65 watts.

[B.friend]

Water Height Anyone~

[davidabrown66]

Originally posted by reefez
No not at all. I said I had one of my overflow lines feeding the skimmer and that line has a valve on it to open or close to restrict the flow as needed. I was probably in the neighborhood of 250-300 ghp going into the skimmer.
The Iwaki pump running 5 feet of head through 2 90 degree elbows and a Squid is pumping more like 800-850 gph and when you split that in 2 1in. overflow pipes running to the sump you have roughly 400-425gph per overflow line. I have one line feeding my Octopus 3000 400-425gph with a valve that I close to get my desired flow through the skimmer.
My point is that with the new Gen-X return pump it is more stable in that I don't have to restrict the flow to the skimmer coming from the overflow. It is way more stable and less prone to a overflow because it has a constant flow of tank water feeding the skimmer.
So I think people are better off running the 3000 with a dedicated pump from the sump or overflow from the tank with no restriction. When I had to adjust the flow to my skimmer with the valve it was nothing but headaches. Now it's more stable.

Ahh yes, now I understand...I was a little slow yesterday.

[davidabrown66]

Originally posted by squin
It's my understanding that for a venturi to work optimally the airway opening needs to be at or just after the transition from a smaller water flow opening to the larger opening, in this case the face of the fitting. By doing this air is introduced into an area of lower pressure, thus creating greater suction.

I've just done some reading as well that supports your thinking.

I can't seem to rap my head around it though, b/c of what we encounter as head pressure doing our own plumbing. It seems to be just the opposite.

But, as far as fluid dynamics go, a venturi or aspirator works when a vacuum is created when the water volume goes from a large cross section (high pressure low velocity) to a tapered (high velocity low pressure) section which causes the vacuum, b/c the water has to speed up to move through the taper. The aspirator or venturi needs to be at the point of the transition.

So, I guess I ruined that venturi unless I can add a restriction to it, but luckily I have my original slightly modified one available still.

Lesson learned: Don't use a spade bit through the whole thing to ream out the whole area where water travels through.

Oh well, part of the fun.

[outy]

how do you guys think the Octopus Recirc Dual Pump Needlewheel 250 would stack up against the ati bm200?

modded 250 course

[davidabrown66]

Too early to tell from my own limited experience.

IMO, I hope with all the mods done on this skimmer that I can come close to the posted performance of a BM200. I like the recirc design on the DNW-200, but sounds like BM has a 160 coming out that's a recirc.

If I can't get at least 25 SCFH from the mods, then I'll probably sell it for a BM200 or BM160 if it comes out soon since I have the sump space now, and I didn't think I would have it when I ordered the DNW-200.

Originally posted by outy
how do you guys think the Octopus Recirc Dual Pump Needlewheel 250 would stack up against the ati bm200?

modded 250 course

[squin]

I can get the airflow up to 23 SCFH, but my wattage has sky rocketed. At 23 SCFH I pull 126 Watts! I'm not concerned about the cost of the electricity, but I am very concerned about the long term impact on the pump life. Running at 126 Watts the pump will easily trip on overload if I stop and restart the pump without letting it cool down first. It should also be noted that when running at 126 Watts the pump is also pulling over 2 amps at a .5 power factor (pf) as measured by a Kill-A-Watt. That is horribly low pf. It should be closer to .9 - 1.0. It looks like the electrical performance of these pumps quickly plummets with any mods.

Does anyone have any ideas on how to maintain wattage while increasing air flow? Alternatively does anyone have any info on the OTP-3000 pump that would indicate how much wattage these pumps can reliably carry?

[charile1]

Should the gate valve mod output be above or below the water level?

[kroe]

squin (and others getting high wattage): Don't blame it on the pumps... something is wrong with your mod. Most likely the mesh is rubbing on something. If not... did you leave your needle wheels on? Both NWs plus mesh will do that... one will result in higher than necessary wattage, but not 120+ watts...

If you have more watts than you want after the mesh mod:

1.) Make sure none of your mesh or zip-ties could possibly be rubbing... this is the only explanation for super high wattage.

2.) If you want lower wattage, less water flow, and more air after getting your wattage withing the realm of sanity, then proceed. Get rid of both needle wheels. Personally I took a hole saw the same size as the stock NW and cut a piece out of a 5 gallon bucket top. I broke all the protruding parts off one needle wheel and used the ring that was left to retain the round piece of bucket top to the impeller. I drilled big holes in the round bucket top piece spaced slightly apart (before glueing the bucket top piece and broken up needle wheel ring to the impeller). I used the holes in the bucket top (after attaching it to the impeller) to attach four layers of Enkamat PF4 with small zip ties. I then trimmed the enkemat so NOTHING was protruding out the back or exceptionally far off the front (past where the stock double needle wheel would protrude). After a couple days of use I pulled the impleller out and again trimmed any stragglers.

Tons of air... less watts than the pump did with the stock impeller.

If you are getting high wattage you are doing something wrong (don't blame the pump).

[kroe]

Also - venturis are not magic, and the stock ones for these pumps suck. Read a bit about how venturis work and you can make your own out of PVC fittings that will do much better than the stock one with any mods. Don't worry about ruining your stock one doing mods, you can make a better one out of PVC parts from home depot by accident.

[reefez]

I have modded the crap out of my 3000 and allthough it is now broken in good and skimming fairly well I don't know if it is compareable to the BM 150-200 of which I have seen and liked what I seen pretty well!

[squin]

Originally posted by kroe
squin (and others getting high wattage): Don't blame it on the pumps... something is wrong with your mod. Most likely the mesh is rubbing on something. If not... did you leave your needle wheels on? Both NWs plus mesh will do that... one will result in higher than necessary wattage, but not 120+ watts...

If you have more watts than you want after the mesh mod:

1.) Make sure none of your mesh or zip-ties could possibly be rubbing... this is the only explanation for super high wattage.

2.) If you want lower wattage, less water flow, and more air after getting your wattage withing the realm of sanity, then proceed. Get rid of both needle wheels. Personally I took a hole saw the same size as the stock NW and cut a piece out of a 5 gallon bucket top. I broke all the protruding parts off one needle wheel and used the ring that was left to retain the round piece of bucket top to the impeller. I drilled big holes in the round bucket top piece spaced slightly apart (before glueing the bucket top piece and broken up needle wheel ring to the impeller). I used the holes in the bucket top (after attaching it to the impeller) to attach four layers of Enkamat PF4 with small zip ties. I then trimmed the enkemat so NOTHING was protruding out the back or exceptionally far off the front (past where the stock double needle wheel would protrude). After a couple days of use I pulled the impleller out and again trimmed any stragglers.

Tons of air... less watts than the pump did with the stock impeller.

If you are getting high wattage you are doing something wrong (don't blame the pump).

kroe, thanks for the reply

I have removed the mesh modded impeller for now, so nothing is rubbing. I am now running the original, stock impeller and the pump is running at 100 watts. The only mods I have in place are a slightly enlarged airway to 11/64th in. and elarged the pump outlet . I realize this increases water and wattage. Was removing the back pressure associate with the pump discharge piping a bad move? Thoughts?

Did you do the mesh mod only? What wattage are you getting?

[davidabrown66]

Well, I got my Dwyer meter delivered yesterday and took some readings.

My modified venturi which opened up the waterway through the venturi with a drilled out venturi to 1/4" actually performed as I expected...worse than the stock venturi that I have with a slightly reamed out venturi on both sides. Here's the numbers:

(A) Stock Venturi no Enkamat: ? SCFH ( to be tested when I receive new impellar and venturi).

(B) Venturi with some reaming of the venturi airway on both sides of the 90 while retaining the original nipple, no reaming of the venturi waterway and no Enkamat: 9 SCFH

(C) Venturi with reamed out waterway with 5/8" spade bit, no nipple and 1/4" drilled hole straight in (no 90), 1/4" tubing trimmed for air input, water and air tight, no enkamat: 7 SCFH

Option B with 2 layers of Enkamat, 10 Lb fishing line: 15 SCFH
Option C with 2 layers of Enkamat, 10 Lb fishing line: 12 SCFH

You might think that C would deliver the best results with increase water diameter and air line input, but reaming out the waterway diameter slightly in the venturi diminished the vaccum that's created = less efficiency.

I also noticed that the venturi's design is not optimally designed if I'm understanding the principle correctly. The air is being introduced at the transition where water is slowing down rather than where it's excellerated, and I think that's why peole are having greater success when they drill straight down into the venturi, b/c that's where the greatest suction should be, but you'd have to leave the waterway intact otherwise you decrease the speed of the water traveling through it.

Another interesting thing I noticed was the decrease in SCFH when the water in the skimmer goes from half full to completely full of water. Is this just water pressure?

So, I see the most dramatic improvement using the Enkamat over stock impellar as others have noted, but need to order another venturi to see if drilling straight down and using JG fitting will increase air flow, and pluck off one layer of NW's to get 3 layers of Enkamat on top and maybe one more underneath.

How much are the Kill-A-Watt meters? Where can I purchase one? Is there specific model I should look for? Anyone know who's stocking venturis and impellars for these guys? I've tried premium aquatics and Aquacave but they only stock the impellar which is out of stock, and I have a call into Coralvue, but no reply yet.

I'm still hoping for 25+ SCFH and for < 100 watts for safety reasons.

I know others are getting this and better from their NW-200's, but IMO I think there significant differences in the design to not be able to compare the results, like the pump might run less efficiently out of water like a Magdrive pump, and there other issues to consider, mostly plumbing leaks, and when changing the input side of the pump, you'll have to change the output side plumbing as well so the pump matches up to the skimmer body again, and ordering extra stock parts for a back out plan, and coming up with a better design that's already in place...you may go through all of this to increase the plumbing 1", but you may increase wattage or decrease overall performance by increasing turbulance, bubble size, and contact time.

I guess you just have to gauge home much DIY'ing you want to do. For me, I like to DIY to a point where I understand the principals so I can apply them, maybe add some creative solutions, so I can save some $$. But I won't spend 3 months to get this skimmer to perform 1/2 as well as something that's only $150 bucks more.

[squin]

davidabrown66,

I purchased my Kill-A-Watt at http://www.supermediastore.com/kilwateldet1.html for $19.99 plus shipping.

[hounddog01]

Originally posted by reefez
I have modded the crap out of my 3000 and allthough it is now broken in good and skimming fairly well I don't know if it is compareable to the BM 150-200 of which I have seen and liked what I seen pretty well!

If you compair the price it may be worth it if you can get it going.

[carlos_fb]

I tried posting this in the other Octopus thread but I didn't get any help.

I did the gate valve in my NW-150 and it's now it's really hard to control the level in the skimmer. Even with the gate valve opened all the way, the skimmer overflows all the time.

Did I do something wrong? Is there anything I can do to fix it?

[hounddog01]

Originally posted by carlos_fb
I tried posting this in the other Octopus thread but I didn't get any help.

I did the gate valve in my NW-150 and it's now it's really hard to control the level in the skimmer. Even with the gate valve opened all the way, the skimmer overflows all the time.

Did I do something wrong? Is there anything I can do to fix it?

What size of gate valve did you use. I believe you needed a 1.5 inch one. I did not see any other restrictions and it looks like you installed it low enough.

I did not do a gate valve mod, just bought a PVC pressure fitting and used PVC pipe for the rest.

[kroe]

Carlos - move the gate valve down lower on the grey tube - you might have to cut the grey tube.

[outy]

exactly what kroe says

[impur]

Originally posted by davidabrown66
Now that mine is skimming, I'm having the same problem. I think this may be normal, since that's where the foam starts to build and therefor deposit gunk. If I set my water level higher, the foam accumulates higher up and therefor less dry foam=light skimmate, but more of it.

I'm hoping that the breakin period isn't done yet, and that I can dial it in a little better, b/c I'd hate to have to move this whole thing to the sink to remove the gunk below the union down to the bottom of the tapered edge to the main body.

Anyone else out there having this problem as well or have a solution to cleaning it when it does this? I'm currently detaching the union, and taking a paper towel to the lower part of the body to clean off the gunk.

After running mine for about 2 months the entire inside of the skimmer body had a brown film on it. I had to remove the skimmer, drain it, get my hand inside with a papertowel to clean that stuff out. It skims much better cleaned.

[carlos_fb]

I used 1" pvc to build it. I was trying to avoid cutting the grey pipe. Is it really necessary?

[Kurt03]

is the gate valve a 1"? my nw200 needed a 1.5"
Is the grey pipe 1" plumbing or 1.5" ?

It looks like your gatevalve is plenty low enough, if you take the gate valve off and leave the rest of your plumbing does the water level drop alot?

[davidabrown66]

Originally posted by squin
davidabrown66,

I purchased my Kill-A-Watt at http://www.supermediastore.com/kilwateldet1.html for $19.99 plus shipping.

thanks!

[pluvialis]

deleted

[markywmson]

it's a NW150 i believe. my roommate has one too, and it's definitely not 1.5" plumbing. i tried mine (NW200) without cutting the gray pipe, but it was way too high. i recommend cutting the pipe down and leaving like 4 inches past the bend. i used a rubber boot that was a bit small, and heated the crap out of it in boiling water... made it fit over the gray pipe and over the 1.5" plumbing on mine. might work for you with 1" stuff instead. good luck!

Originally posted by Kurt03
is the gate valve a 1"? my nw200 needed a 1.5"
Is the grey pipe 1" plumbing or 1.5" ?

It looks like your gatevalve is plenty low enough, if you take the gate valve off and leave the rest of your plumbing does the water level drop alot?