I'd be interested in those articles too...

Dig Brad Dig!! :mrgreen:

Not that I'm disagreeing with you, but, ... Actually what I was thinking about had more to do with sump size versus turnover, not the "snuff of your plumbing" or your water level, or even the velocity of each individual return :rolleyes: If you have a smaller sump, like, say, something that fits in your tank AND gives you enough room for pumps, other equipment, etc., you may just find yourself in a situation where the flow through the baffles is still so fast that bubbles can't clear by the time they hit the pump inlet. Thus --> microbubbles. A higher sump level MIGHT help in this case, but, you still want the level to be low enough so as not to overflow the sump in a power-off situation.

Tony, I agree. My first attempt at a sump years ago resulted in me going near insane battling micro bubbles. Reducing the flow solves this, until I was able to get a bigger sump.

P.S. Don't listen to Steve, he's crazy! :razz:

What's the big deal with micro-bubbles?

Coming from a guy with more experience keeping fish than corals this would seem as more of an advantage than a disadvantage.

bah, I actualy have about 5000 gph flowing through my sump alone (only 1200 goes back to the tank though) so aprox 5000gph through 20 gal water volume in a 33 gal sump (250X turnover rate for the sump) and no micro bubbles. so it comes down to how well you though out your baffles and the arangment for the high flow capacity. I agree if I would have put my baffels closer togeather the velocity of water would probably carry over bubbles to my return pump suction.

Steve

I am putting together a system which consists of a 50g main tank and a 20g tank for a sump with duel returns. I was led to believe that the more flow the better so I got a mag 18 for a return pump, but From reading this post I'm starting to think that I have to much flow for the size of my system. Right know I'm still researching my sump design so I have no baffles yet, Do you guys think that this is to much flow for the tank and if so can you pinch back the pump to reduce the flow

I have a 20 gallon with a blueline hd20 acting as a return from the 20g sump - after losses about 350gph (17X). I added a maxijet 1200 to get some more flow and now I'm around 32X turnover. I really don't want a powerhead in the tank so I recently purchased an Iwaki 20rxlt (or whatever its called) to serve as return and will try using the hd20 on a closed loop with a scwd. I have found that too much velocity of flow can be an issue but there is no such thing as too much flow itself.
I don't know where the "low flow through sumps" originated but the only place I can think of it applying is for microbubble prevention. I keep live rock and macro algae in my sump and have a high flow (~30X becaues I added a maxijet there as well). I believe that with two 20gallon tanks connected via a high turnover, my protein skimmer functions just as it would on a single 40gallon tank. I also believe that if a healthy turnover rate is good for a main tank it MUST be good for a sump - those rules wont change just because one of the tanks is lower than the other in the stand. That's just the way I see it... ?

- Chad

no not to much as long as you do it properly ro reduce the water blast comming from your returns. also on the discharge of the pump you can put a "T" with a valve to return some water back to the sump to control your flow.

Steve

Nothing, they're just a visual nuisance.

Or if your sump was shorter, like in, say, a 20g instead of a 33g.

the only place there are bubbles is in the sub chamber of the first of 3 main chambers. the sub chamber probably causes 90% of the bubbles to be removed and the other 10% can't float down to make it under the first baffle to the second chamber. one of my designs that actually worked on the first time :rolleyes:

Steve