sump water level

[Brett Stiefel]

Ok. I can't find the specifics I want in any of the material I have read. This probobly means that it is dead simple and anyone even slightly aware would see it right off. I am building a system with a sump. I have read that I do not need valves to regulate the water flow into the sump if I use an overflow box. I see that as long as the sump can hold the water from the overflow box you will not drain the tank from that end and if you put a backflow valve in the return you are ok. However what is to keep the overflow from draining too fast, losing suction and then the pump draining the sump. This would still cause a flood and and burn out the pump. What am I missing?

Also I want to put a pre-filter, co2 injector and fluidized be filter in the sump. Should I do this inline or as seperate units with seperate pumps. Should the pump be at the front end or back end, whether of a whole line of equipment or each individual piece? I have always used in the tank or hang on the back equipment but I don't want to look at it. Also, I want to set up a reef at the office and I only have room to go up not out. If I built a very tall tank it would not get enough light. Building the sump will let me get around this by having a large water volume for stability but a smaller habitat for view.

[ron v]

The drain from the overflow box to the sump is gravity fed. It does not work by syphon. Do you have an internal overflow box with a standpipe or external with a syphon tube. If you have the external, box type, then the syphon is from your tank to your overflow box. That's where a problem can occur. If you loose syphon from tank to overflow, water stops flowing to your sump. When the sump empties, the pump runs dry and sets the house on fire. LOL. Maybe not, but that is why the internal with a standpipe is best. With a syphon tube, there is no solution. Everyone has that problem. You could use two or even three syphon tubes. If one goes, maybe the other won't.

Never use multiple pumps inline. You can't get them coordinated to pump exactly the same.

[Brett Stiefel]

The plan I looked at has both. There is an internal box to skim and an external box to feed the sump. I don't want the internal type in that it would necessitate my drilling an existing tank. I don't even know the type of glass. This could cause a problem. Oh, that brings up another question I had. What is the purpose of two boxes. Why not have one box inside and just syphon to the sump directly. Also, I don't see how the interal box would fix the problem. It just seems that it would change it. If the feed was to fast compared to the pump the overflow box would go dry and the same thing would happen by another means.

[ron v]

Originally Posted by Brett Stiefel

just syphon to the sump directly.

You don't "syphon to the sump". The only type overflow I know about uses a "standpipe" to regulate water flow to the sump.

[leveldrummer]

you have two boxes on an overflow, one inside and one out side... there is a tube connecting them, that tube keeps the syphon going, the reason you have two boxes is that the syphon tube has to stay submerged on both sides to keep the syphon, if you get air contact at either end, it will drop the water out as bubbles rush up. the over flow box wont syphon the tank dry because it only takes what water is given, if the pump on the sump goes out, it stops adding water to the display tank, and what ever is in there evens out and stops flowing into the overflow box... the only problem with this system is if your loose your syphon... they make over flows that you hook a small air pump up to in order to stop that from happening, i would suggest that if your worried about it, but many people use the other type with much success. its just a super safty precaution. hope that helps

[TheOldSalt]

The two-box setup is there to keep your tank from draining all over the floor. It is an automatic siphon break which also serves as an automatic siphon preserver. An engineering marvel, no doubt. The water doesn't flow through either box until the sump pump dumps water into the tank. This keeps things safe in a power outage.
Your prefilter can go into that box, by the way. Otherwise you have to set one up in the sump wherever the water enters it.

As for burning up your pump if it runs dry, I think you'll find that it's awfully hard to get a pump to actually run dry. As long as you dont make the mistake of putting the pump's intake well below the pump itself, the water level in the sump around the pump will still be high enough to keep the pump wet once it can no longer pump any water. On the other end, however, your tank might overflow. This is the main reason that overflows are made to be drains, not siphons. They stop doing anything when the power is off, and start working normally again when the juice is restored.

Why do you want to add CO2? With a fluidized bed filter your ORP will be plenty low enough.