Air bubbles

[lucydlpn1]

Hi,
I have been using an overflow box and old bio ball filter with out the bio balls on my tank. The overflow box is rated for 600gph and the pump is rated for 600gph but I keep getting air bubbles because the pump isn't getting enough water. Here is my question...What size water pump do you use when your overflow box is rated for 600 gph? Obviously not 600 gph pump
Any help is appreciated
Lucy

 

[Brian5000]

The charts on the pump selection guide show how much flow a given pump generates after pumping water up a given height. Select "more info" on the desired pump to see if it will work for you.

http://www.reefs.org/library/pumps/

You'll have to figure out how high you're trying to pump the water and how many corners the water has to turn. Then guesstimate from there.

My overflows are rated for 600 GPH. The water needed to be pumped about 5 feet through flexible tubing. I got a Magdrive 9.5 which says it's about 750 GPH at 5 feet. After accounting for friction and the fact that the tubing path does twist a bit, it ends up being even less than 750 (I don't know exactly how much, but seems to be close enough).
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history recession

 

[Len]

The pump selection guide is a great tool. I'd go with a pump that outputs about 1000gph at 4-5' of head. You can always choke down the pump's output with a valve if required. Another simple idea is to add a gate valve to the downpipe from the overflow. You can close the valve enough so that not so much air is getting sucked down into your sump. I know you might worry it will clog over time. In my experience (10+ years using this method), this is very unlikely.

 

[lucydlpn1]

Thank you. I used the table and bought a new pump but the air bubbles continue and after the water explosion(Yes I ruinned a newly painted ceiling) I have decided to give up on the overflow box and sump. I have gone back to using my old eheim minus the sponge ( Don't want a nitrate spike!) Does anyone think a reef tank can be safely run with live rock and cannister filters? And if it can do you have any suggestions as far as protein skimming. I can't run a skimmer in the tank because it won't fit unless I get a new light. I currently have metal halide with power compacts and it takes up alot of space. Any help is appreciated