Flow rate through sump

[yakfishin]

I have a 215G aquarium that I'm just about to start up. I have a 30G sump that is linked by bulkheads to another 30G tank that will at some point be a lighted refugium. This system is being setup as a hardy soft reef tank, with the main emphasis being placed on fish and not corals. I read so much about the recommended flow rates for the entire aquarium for different setups, but I can't find much information on how much flow should be going through the sump itself. Can anyone give me a recommendation? I do already have my plumbing done, but it isn't anything that I can't change. Right now I have 2 mag 7.5's returning water from my sump to the tank and I have estimated that this is giving me about 1200 GPH's. I'm shooting for a flow rate of about 13-15X for my total system, so the sump and refugium is taking care of about 5 1/2 of that. Is that a good figure for water flow through the sump? I have 2 vortechs to make up my additional circulation within the main tank. Thanks for any replies.

[mg426]

5 1/2 turnover is on the high end of what people are running now a days, but if you have no Microbubble problems it should be AOK.

[yakfishin]

No micro bubbles with my freshwater test, however, because the tank doesn't have any livestock in it yet, I haven't run the skimmer. So I guess I will have to wait and see. If it's on the end, at least if I have any problems with noise or bubbles it is good to know that I can back off on the flow some and be ok. Thanks.

[poppin_fresh]

I personally am a big fan of slow sump turnover. I orginally had a sump under my tank that ran at 9X. I had bad microbubbles and very poor skimmer performance. My current basement sump runs at about 3X total tank volume. It works much better for me with the slower turnover.

[Shagsbeard]

You wont see microbubbles in freshwater for the same reason that skimmers don't function. The surface tension in fresh water is too great to support such small bubbles.

[yakfishin]

Thanks all. My sump setup is a container within a container system. I have a small plastic tub about 13x15" which has a slit cut out near the bottom for water to drain. That tub sits in a larger tub, with the top of one side (opposite of where the skimmer box drain is located) cut down for water to pass over. At that point in time the water is passing into the largest tub at the furthest point away from my pumps, about 20". I placed another cut out container in front of my pumps to act as last chance deflector in front of the pumps. I'll keep you informed as to how it all works out when I perform a saltwater test this weekend. I did some searching online, and it sounds as though a 5X turnover for the sump is a good flow rate. My flow rate also matches fairly closely with the rating for my skimmer pump, which I have also read is a good thing. Wish me luck, I'm hoping I don't have to do anymore plumbing work and can soon actually start to enjoy watching other than water within my tank!

[PatMayo]

Some folks recommend higher flow rates in the sumps to prevent dietrus and other nutrients from building up. If the sump is large enough and the water plumbed correctly microbubbles won't be a problem. I think Anthony Calfo suggests a higher sump flow rate.

Ultimatly it boils down to what works best for your set up.

[nekomi]

How do you determine flow rate through the sump? I suspect that this might be the cause of my microbubble issues (caught them during a FW test). I have a 10g sump running under a 37g tank. I have a Quiet One 3000 pumping water back into my display, plus a Maxijet 1200 for my skimmer (Aqua C Urchin), and a Maxijet 900 for my CPR Aquafuge, which is hanging on the sump.