Flow vs Turnover...

[DarwinFish11]

Hey all, hope the summer is going well!

I have a few questions here that are brought up as a result of two issues I have been having.

The first is a micro bubble problem....I had this for quite a while and could never find the problem. I isolated everything and still nothing. Added a new sump with extra baffle and still bubbles! So I finally kept turning down the flow on my return pump and they finally started to disappear. So they seem to be generated from the overflow into the sump, and once the amount of water through the overflow was reduced the bubbles we not generated anymore. I am running a Blueline HD 40x and I am guessing it is turned down about 1/2 way. The flow should be about 1100 so at 4ft so I am guessing I am getting about 500-600gph return.

A second part to this is that i have added 2 Tunze 6045 (1200 gph) to the tank to up the in-tank flow and help with a cyano problem (also running phosban reactor with Rowa-phos now). The only reason I could turn down my return enough is because I had added more flow with the Tunze.

So two questions....how much total flow should a 90g have? I am running about 3000gph now I guess.

The second is a bit tougher and open ended, but I always here about "flow" but no one differentiates between in-tank flow vs the turnover of the water through the tank? I have seen a 90 with a trickle running into it and I could have 1000gph plus. Is there a standard amount of turn over you should have? I am worried I have too little now, but if I up it I get my bubbles back.

I am interested to see some responses to this.

Cheers

[bertoni]

Various animals require different amounts of flow. 3000 gph for a 90g tank should be fine for high-flow animals like Acropora, but some people go higher. I don't think a higher flow rate would do much for cyanobacteria problems.

The turnover through the sump is critical ostly for skimmer performance, assuming that's where the skimmer is. I usually suggest about 3-5x the tank volume, so your setup seems fine as is. There isn't much real data on sump turnover, though.

[DarwinFish11]

So Re: Turnover the less movement through the sump the better skimming I would imagine? That would make sense to me since I get more skim now than with a much hight flow through it.

[sabbath]

I have a Tunze 6045 in my system. Just fyi this unit has been running at around 950gph or so in out side test results. I really like mine but just note those numbers's are a little generous.

[WDWDen]

I was getting tons of microbubbles in my 180 also. I could not get rid of them. Yesterday, I backed down my pumps to about 3/4 open and the bubbles have been cut down drastically. The pumps also run more quiet. They always sounded as though there was a piece of paper stuck in the pumps. Now I'm thinking that sound was air. The farther I back down the pumps, the more quiet the paper sound is. I'm willing to bet I'll get even less bubbles.

Sorry I can't really help with your questions. I just wanted to voice my observations. Good luck.

[conefree]

Run your overflows into a filter sock, or run the piping into a partially submerged T fitting. When the water gets to the sump, the T allows the bubbles to go up and pop while the water goes down. Good luck!