Starting a 3 tank 70 gallon system looking for ideas.

[OceanBoxReef]

I’m gonna have a 40 gallon tank as my main display. A 20L as my frag tank and 10gal sump slash Refugium and I wanna tie it all
Together. Pics are for ideas of what I have in mind. Anyone have anything similar?

 

[tbrown]

Are you planning on 2 return pumps or a single return pump into the frag tank overflowing into the 40, overflowing into the sump?

 

[tbrown]

1 thing to consider - a bigger sump may be necessary since it'll need to handle the water from the 40 and 20 in the event of a power outage or any return pump failure or need to shut down.

A larger sump would be recommended in my opinion since you're looking at a 20 long and a 40 tall. Surface area plays a big role - much larger role than total system volume in my opinion. You're looking at 78" * 12" surface area which is slightly more than a 90 gallon tank's surface area. Depending on how much drawdown you have after pump shut down, you're going to have a significant amount of flow that the sump will be required to handle.

The 10 gallon tank has a surface area of 200" squared vs the 936" squared for the DT and frag tank. For every 1" of drawdown you'll need 5" in the 10 gallon sump across the entire tank though, not just the middle section.