Return pump Help!!

[PMAC]

Recently I decided to add a wet/dry system to my 29 gallon tank. Things we're going pretty good for the first night or so, but now my sump keeps draining below the minimum water level line and i have to fill it up with water. I think the guy at my LFS sold me a return pump that is way to powerful for my 29gallon tank and that is why it is draining so quickly. Can anyone help me out with what kind of return pump I need??? Thanks guys!

[The Clownkeeper]

What type of pump are you using? Many use a ball valve on their return pump to :throttle" it back a bit.

[PMAC]

Im not quite sure what kind of pump it is because he gave it to me as a used piece from another tank, he said it filters around 700gph and i have no idea how many gph is good for a 29 gallon tank.... as for the ball valve, does it thread right on to the pump?

[Reefland]

How are you getting water from the tank to the wet/dry filter? If the return pump is pushing too much water then the tank would be overfilling. How much water are you having to add each day? Sounds like it is normal evaporation to me.

[PMAC]

Well i dont have the tank full to the rim, so the water that is returned from the sump actually fills the tank up slowly... i end up adding about 1/2 gallon of water to the sump everyday,otherwise it forms a whirlpool and sucks air in and spits it out violently into the tank, that swhy i felt like the pump might be too powerful for my setup.