DIY Sump Tank

[nomar5050]

Hello,

I'm in the planning stages for building a sump tank for my 30 gallon reef tank.

At the moment I'm planning on using a 10 gallon glass tank I had laying around (I also have a spare 30 gallon, but it seems over the top to run a 30 gallon sump on a 30 gallon tank).

Anyway, I've read a lot of articles on them, but very little information about how to pick the size of the return pump. Unless I'm misunderstanding the dynamic of the sump, the size of the return pump has to be perfect. Too strong of a pump and the return section will constantly be going empty, and too weak and the return section will always be overflowing. Am I correct in thinking this? And if so, how do you get those dynamics perfect?

Thanks

 

[AlexStinson]

The most simple answer is that your return pump needs to be less than what your overflow is rated for, Gravity handles the rest. Remember when you do this to factor in head pressure, and if you want to run your return pump into a manifold that feeds other items, like a skimmer or media reactor.

 

[TaylorPilot]

The water level in the sump has nothing to do with the speed of the pump. It has to do with how much water is in the sump. I will give one little exception. Typically, the water level in your display will rise a little when the flow increase, which will lower the water level in the sump, but all you have to do is add more water. Typically, people run anywhere for 5X-15X turnover. So if you have a 100 gallon system, you would want between 500GPH-1500GPH. The wider (front to back) your sump is, the more water in can flow without making noise. You will want some sort of baffle that keeps the water level constant in the front (skimmer) section. That way when the water evaporates, only the water level in your return (circulation pump) section lowers. That is the section you will want your ATO sensor in. There is allot more to it, depending on your overflow, drain lines, and if you want mechanical filtration (filter socks). But that should give you a basic understanding. HTH

 

[TaylorPilot]

The above comment on just making sure your return can handle more flow than the pump can put out is dead on. Only thing I would add is to add some cushion. Don't get a 1000 GPH pump when your overflow has a max rated flow of 1000 GPH. Three reasons. Firstly, I doubt it will be very quiet at it's max rate. Secondly, if something were to block a part of the overflow such as a dead fish, or a piece of nori that broke free from the clip, it could cause the system to overflow. Finally, when the pump starts putting water back into the display from the sump, there is will be a slight rise in water, this will reach an equilibrium and the water level in both your display and sump will set. If it is a smaller overflow and the level rises more, your sump will need to be larger to handle all that extra water as the system drains down to the bottom of the weir.