Need an idea for a fuge on over flow #2

Ok so this is my tank


Im putting a 20L under the tank which will be sump #1. It will be a bio ball chamber leading to a skimmer chamber overflowing to a return pump chamber which will have a auto top off float valve from the RODI.

The question is if I add a second 20L as a refuge do I need to have it dump into sump #1 or is there a way to have a separate return pump in the refuge with out having to worry about the possibility of a pump failure on either of the sump from causing a spill.

My thought process tells me that if one pump fails or is slightly less powerful it will cause the other sump to spill over.

Is there a design to allow 2 sumps with out having this issue?

 

Why not just run both overflows into your sump. Place it on something under the sump tank to elevate it some and let it overflow into your fuge. Then you will only need one pump that is powerfull enough to keep up with both overflows.

 

Thats probably the safest way to go. Ill probably elevate the refuge and spill it over to the bio balls/skimmer sump.

 

Ya probably better that way. More filtration before the water hits the bio balls that way. If your fuge is running well it should suck all nutrients out before it even gets to your bio balls leaving them only as a backup rather than depending on something most people dislike. are you building this your self?

 

Ya, I picked up a 20L for $30 at petsmart and im going to head out and get another for the fuge. I have to drill the second tank for the spill over.

Im walling the chambers with 1/4" cell cast acrylic and putting a MSX200 in the first sump with a MAG7 as the return. I was going to go with the MAG9 but I dont know if it will be to powerfull.

I have 2 true 1.5 Durso standpipes on route so no matter what my flow rate of the MAG is, the Durso's should handle it.

Lights are next on my list. Thinking about 3 250 14k