Bulk Head size

[shookbrad]

I Can anyone tell me what size bulk heads I should put in my aquariums.
I have 2 35 gallon tanks on top of a single 75 gallon tank the 2 35's will feed into the single 75 and the 75 will feed into the sump. the sump will pump water back into the top 2 35 gallons. it will lool like this.
________________________
|ooooooooooo|ooooooooooo|
|oooo 35 oooo|oooo 35 oooo|
|ooooooooooo|ooooooooooo|

[hr]
|ooooooooooooooooooooooo|
|ooooooooo 75 oooooooooo |
|ooooooooooooooooooooooo|

[hr]
|ooooooooo|
|oo sump oo|
|ooooooooo|

[hr]
I don't want the 2 35's to feed the 75 faster than it can drain into the sump.
I would like a high GPH turn over I plan on getting a high powered return pump so I don't have to put powerheads in the 2 35 gallon tanks.
Thanks,
Brad

 

[yeffre kix]

You can fine tune your flow with gate valves to get the levels even but its a lot of work. Of course things will change with time too as you get algae in the intakes or a snail blocks the overflow. Too many variables. You might try to plumb each tank individually to the sump. With a large pump you should be able to get the flow you need by using T's in the pvc to run to each tank. Run the drains out of each tank and they can be joined together below your large bottom tank before reaching the sump.