very short intervals

[justinl]

sorry, I probably should have explained. Im currently raising copper rockfish (Sebastes caurinus) larvae at work and there's currently a big problem with having the initial birth of larvae settle on the bottom of the tank and suffocating there. The idea is to have a slow rpm fan (underwater) come on for a few seconds to blow the drifts back up into the water column, then turn off for a few minutes so as not to damage the very very delicate larvae. It only takes about five minutes for the drfts to start accumulating.

We also have oxygen bubbling in the tank but vigorous bubbling will kill larvae so that's not an option.

edit: also, because it is not for a powerhead, but for a fan instead, i need the controller to accept a standard three prong plug.