Advice on new sump build

[compchick813]

I am planning a new discus setup in my 125 (the 12 juvies will grow out in a 55 first). I currently have 2 Marineland C-360 canister filters from when we had African Cichlids. I would like to switch to a sump. Still deciding on the size, but I am trying to plan out the plumbing. I am thinking about getting 2 overflow boxes. I was looking at these:

http://www.thatpetplace.com/reef-octopus-ob300s-overflow-box-250-gal

I'd want to have the second just in case one loses siphon. Would I have a lot of overflow noise from having 2 overkill overflows? Those have a 1.5" drain - should I reduce that down? I think I'll get a Quiet One 5000, which would provide between 581 gph (built-in valve closed) and 1041 gph (built-in valve open) at 5'. I would do 2 returns from that, and it seems like most people do 2 x 3/4" returns. Should I do different drain or return sizes?

I plan on putting both a siphon break and check valve for the return. I found this float switch below that I would put in my sump (at the proper low water level) to both keep the main tank from overflowing and the pump from burning up if both overflows lose siphon.

http://premiumaquatics.com/store/merchant.mvc?Screen=PROD&Store_Code=PA&Product_Code=UL-FS10A&Category_Code=

Any advice or flaws in my plan are welcomed!

[discussmith]

Take the money you save from not buying a second overflow and purchase an aqua lifter pump instead. Take the tube from the aqua lifter and attach it to the nipple in the middle of the overflow you are looking at and you will not lose siphon as it slowly pumps a small amount of water out of the overflow thus maintaining its siphon. If you decide to go with the second overflow anyway I would still purchase the aqualifter and connect them both.
You can never have too large a return. I'd leave them as big as possible. The flow rate is determined by the pump so they will not drain any faster than they are filled, but if you make them too small they can be overrun. If noise is an issue there are numerous ways to make overflows much more quiet. Do a google on overflow noise and you should find many articles and videos.

[compchick813]

I didn't know about the aqua lifter. Awesome, thanks! I will hook one of those up to both overflows.