sump baffles

[bighead]

I have my sump compartments all figured out but what height do I keep the baffles at I understand my overflow (entering Water) willbe the Highest baffle and my bubble grab consists of three peices of glass it is the height that BAFFLES me

the sump will be made of a 40 gal breeder tank first compartment overflow aprox 12.5 in 2nd compartment fuge apron 12.5 in then my bubble trap then last return remaining space about 10 in

My DT is a 90 Gal RR tank

[Johnz]

I did something similar recently with a 55. I just kept the height a few inches below the top of the tank. It's not really critical, but you do want the baffles for the second chamber to be a little lower than the first. You want to make sure the water always cascades and the surface always moves. Otherwise you end up with surface film.

[sleepydoc]

The heights need to get progressively lower, as you have indicated. Not hugely so; 1/2~1" should do.

You need to take your skimmer into consideration - different skimmers have different water level requirements. You don't want to end up with the water level too deep and not enough 'head room' above to keep your skimmer.

The other consideration is back-flow from your tank in case of a power outage. You want to keep enough room in the sump to handle any back-siphoning of water from the DT when the power is lost.