Needlewheel to Meshwheel skimmer mod

[Delphinus]

I think it will get better as it settles in but you might want to think about slowing the feed pump maybe.

That's awesome you get such results, I didn't get anywhere near that kind of "my cup is overflowing like crazy" type results and I thought it was maybe because of the Sedra .. so you just proved that theory wrong.

Can you snap a picture of the pumps? I'd like to see how they sit on the skimmer itself, maybe I can change how I have mine and get some more improvement that way.

[Jaws]

Originally Posted by Delphinus

I think it will get better as it settles in but you might want to think about slowing the feed pump maybe.

Can you snap a picture of the pumps? I'd like to see how they sit on the skimmer itself, maybe I can change how I have mine and get some more improvement that way.

It's not a recirlution skimmer so there are no feed pumps other than the actual pumps I did the mod to. I've been running one pump at a time for 8 hours each to try and help break them in. With only one pump turned on it sure generates a lot of foam at the top after a while but because there's only one pump on it's not enough to push the foam up the neck so it can overflow in to the collection cup. As soon as I turn the second pump on the water level goes right up to the top of the neck again and overflows wet, large bubbles in to the collection cup filling it up pretty quick. The bubbles overflowing are large because there isn't enough height to form a foam. I've also noticed quite a increase in turbulence in the skimmer including the neck and not all the bubbles are really fine. There are some bubbles the size of a tic tac hovering around in the neck too. I've also adjusted my auto-topoff so the water level in the sump drops which has always lowered the water level in the skimmer too. I'll see if that helps.

The pumps sit horizontally just like in this picture:

http://www.jlaquatics.com/phpstore/s..._ID=ps-errs250

[Delphinus]

Huh - go figure - I had figured that all multiple pump skimmer designs were recirculation style. I.e, the pump draws water from the skimmer body and the water feed to the skimmer itself is independent of the needlewheel (meshwheel now) pumps.

I had to mod my ASM to be recirculation, basically all I did was drill a new 1.75" hole (the 1" uniseal requires a 1.75" hole same as for a 1" bulkhead) and hooked the pump in that way. For the last year I've been feeding the skimmer via a T off the overflows, now I'm feeding with a maxijet 600 (after trying a maxijet 1200 for the last week). I read on asmskimmer.com/octopusskimmer.com that for a recirc skimmer you want a feed pump about 1.5 times your tank volume (but I'm not sure if that number is just a WAG on their part - I don't know if there are any metrics applied to generate that factor value of 1.5).

Seems to me you might need to think about modding the skimmer itself. The problem is that the pumps are just pushing too much volume of the air/water mixture for the exit pipe to carry out fast enough. You could start by trying to raise the skimmer so that there is a larger height differential, but it sounds to me if you're racing water through the skimmer that it doesn't have a lot of contact time. So going towards a recirc mod on your skimmer might be something to look at.

I'm not sure what I'd do. Bear in mind this is all black magic to me, so don't just follow MY advice because I'm clueless!!

[Chin_Lee]

jason
try to control the amount of air entering the venturi with a small valve and it should decrease the bubble level. as the pump breaks in more, increase the air flow to raise the bubble level.

[Jaws]

It's actually already started to settle down and I got 2" of stuff in the first 24 hours. It's definitely not as dark as the old stuff but it used to take a week to make what the mod has done in 24 hours. So far I'm happy and look forward to seeing the long term effects of this. The water line is still almost right to the top but the skimmate is thicker and darker now than the wet bubbles that it started pumping out first.

[Delphinus]

Originally Posted by Jaws

It's definitely not as dark as the old stuff but it used to take a week to make what the mod has done in 24 hours.

This is exactly my results - in fact it can pull out more in 24 hours than it used to make in a week. But the skimmate is definitely lighter. I used to pull out "Coca-cola black" skimmate, now it's more like "green tea".

But I wonder if it's not unreasonable to expect a lighter skimmate than before, if you're pulling it out faster maybe there's less DOC to pull out?

Because that my airflow hasn't increased and it doesn't appear to be a more voluminous (is that a word?) foam (like what others are claiming on RC), I'm reluctant to try lowering my water level (by opening the gate valve) too much because I'm afraid it will hit a threshold and basically stop producing skimmate. I'm still planning on modding the venturi and maybe the volute to see if I can pull the air volume #'s up a tiny bit.

[Jaws]

For me I think the color and thickness of the skimmate has to do with the water level in my skimmer. When I only had one pump running at one time and the water level in the skimmer would fill the reaction chamber, there was a nice thick foam that formed on the top. The fact that the color is weaker only makes me think that given a longer skimmer neck the foam would be thicker but that still doesn't mean that it's not pulling out the same amount of crud with wetter foam. It just overflows sooner and doesn't have a chance to form that thick foam. I can't see this being a downfall but I could be wrong.