Converting from standard 75 AGA to a 90 AGA

[Doodaa]

I have access to a free 90 gallon Standard AGA. I'm thinking of dismantling my 75 and replacing it with the 90. Same footprint, just 3 inches taller.

Right now I have silica play sand for a substrate, which I want to replace anyway. It's working fine, has lots of life, no more clumping, but it's not aragonite and it just bugs me that it's in there.

Since it's the same footprint, I can use the same equipment that I'm using now...mainly lights.

There are two main reasons I want to do this...

1)It's a free tank from my parents. Was freshwater, but no copper treatments in the last 5 years...before that, who knows.

2)I want to make a deeper sandbed than my 4 inches right now and out of the right stuff (aragonite) and am thinking of burying some PVC piping for a closed loop system for better circulation.

One benefit for sure is more TWV for stability.

Since this is a standard 90, I am thinking of drilling holes in it and installing an overflow like this *click* (silent and failsafe overflow).

Looking for some comments or feedback on the pros and cons of my plan. Any suggestions on the closed loop? or comments on bottom to top flow for circulation? I'd like to start out more right this time.

oh and starting with a fresh sandbed...how will that affect my system? Do you think there will be a pretty hard cycle? Should I slowly remove my old sandbed before converting? I do have some SPS corals now that are growing pretty quickly so I figure my stuff is good now.

Just looking for helpful suggestions

Thanks!

[charlie]

I don't think that I would bury the PVC. If you ever had a problem with the closed loop, you would be tearing the tank apart to fix it.

[Doodaa]

I don't think that I would bury the PVC. If you ever had a problem with the closed loop, you would be tearing the tank apart to fix it.

Good point Charlie...I was throwing some thoughts out there and wanted comments like that.

Anything else? Anyone?