Yeah, you can buy Kilz at Lowes, HD, Walmart, etc., while you're buying your paint.
I don't know about using the drain so I'll take Aquanooby's word for it. Just wondering though, do you have access to a sink? I would personally not keep a 90 gallon in any location where I didn't have use of a Python, LOL.
Can you send me a pic of the gravel and a link where I can get it as I seem to be having a difficult time finding it.
There are 4 substrates I'm currently considering:
1. Activ-Flora ("planted aquarium substrate")
2. Super Naturals Aquarium Gravel
3. Quikrete All Purpose Gravel
4. The biggest substrate you can get at Petco (at least my petco)
Large substrate (like river rock) can be really hard to keep clean IME. I swapped out my Top Fin river rock a long time ago because the detritus easily sinks to the bottom through the big gaps in between each stone. It was a gravel vac nightmare for me.
I would really like some natural looking stuff that would be easy to vac and that would make the ph better for south american cichlids as where I live the ph and water harness is perfect for lake Tanganyika cichlids and not south american cichlids.