Need advice on 'fuge sump foundation and noise from overflow

[Kahuna]

Hi. I've been "collecting" hardware and items and scrimping and saving, and finally, my 90g reef tank is undergoing leak check with fresh water as we speak. It's taken five years to get here.

I need to get an answer regarding the "foundation" under my acrylic refugium sump. It's an approx. 35 gallon unit from Sea Life Systems, and is approx. 30" long, 16" wide, and 18-20" deep. I have it sitting in my oak homebuilt (from a DIY kit out of Lebanon, TN) cabinet on expanded polystyrene insulation foam from Lowes. This is the white stuff; looks like tiny balls cast together. It's about 1/2" or 3/4" thick. This OK for this use? It's supposed to last for 20 years as an insulator for house walls. Please advise. Tie it together with the issue below before answering, please.

Also, my tank is a all-glass unit that is bottom-drilled at each end. The overflow is 2" PVC that is rounded and has 1/4" slots milled in it about 3/8" from the top. This runs to a 1 1/4" bulkhead fitting, and then through about 24" of grey cuffed flex pipe that runs into the 1" inlets on the sump at the bubble filters.
I know that the overflow is going to gurgle; any fixes for that?
I also want to hard-pipe the overflow return to the sump to reduce noise from the grey ribbed plastic hose, but am concerned that the foam under the sump may collapse over time and put strain on the top sheet of acrylic that forms the sump. Is this a concern?

Thanks in advance for all advice.

Cheers.

Kev

[chimmike]

well, for one thing that grey cuffed flex pipe is going to make it louder. Pick up some spa-flex. The smoother and more laminar the flow, the quieter it will be.

If you really want it to be silent, go to beananimal.com and look at the silent failsafe overflow system in his projects area. It'll take some work on your park, maybe drilling, to get that installed, but it'll be worthwhile for eliminating noise.

yes, that styrofoam is fine.