Sump question

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Aquarium Advice Activist
Nov 16, 2003
San Francisco, Ca.
Im thinking abou picking up a 30 gal saltwater system and a wet dry filter for a FOWLR. My question is, if something breaks, can the tank overflow? If so, what preventative measures can I take to avoid this. I want to get Mr.5150's deal that he has in the classifieds of this site, let me know what you think.

I have had my tank set up for about 6 months now and have not had a problem with my sump yet. I do have a question about overflowing though:

Let's say I am not home and the power goes out. The pump will shut off and the tank water will drain into the sump until it gets below the overflow box. This will fill the sump considerably, but I know it will not overflow it. This part I have tested. My concern is this. If the power comes back on and I am not home, the pump will begin to pump back into the tank but there will be no flow back into the sump becasue the siphon was lost when the water level went below the overflow box. So, the pump will push water back into the tank until the sump is empty and that WOULD cause an overflow. Any ideas on how to prevent that from happening????

I am not sure how you would accomplish not breaking siphon in an overflow tube return. Maybe someone who has this set-up and has licked this issue can respond :?:

One design that I know that elimiates the problem is the use of an overflow box. This is usually installed in-tank (usually in the corner or mid point on the back) and it is plumbed from the bottom of the box to the sump. It is a sealed box and has openings for tank water to drain into that is returned to the sump. There is no siphon to worry about. If you pump shuts off, the tank will drain to the sump to bottom level of the holes in the overflow box then stop. When you re-start the pump, the tank level rises and water overflow commences. Simple and foolproof. As a matter of fact I take advantage of this in feeding my reef tank. I use the Red Sea wavemaker which has a reef feed mode that shuts off the MP and all but one PH. This allows food to reach the corals at the bottoom of the tank and prevents a lot of food from being sucked into the overflow - waste and NO3! Works really well. I think that there are some retrofit overflow box setups but it will require you drilling your tank. HTH
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