"I was thinking of using plain clay cat liter since I have a bag. Would anyone recommend this as a substrate."
Yes, I would recommend clay cat litter. I use Special Kitty brand pure clay cat litter. The plants grow really well. Here is a video of my aquarium that I took yesterday evening: http://www.youtube.com/watch?v=K3Y8a8TYXjk
Here's a photo of the roots in my kitty litter tank a few years ago, growing deep down into the kitty litter: http://gallery.nanfa.org/v/members/Eric ... 5.JPG.html
That's back when my tank looked like this: http://gallery.nanfa.org/v/members/Eric ... e.jpg.html
Kitty litter is highly regionally variable because it's usually local clay that's mined up. The clay from different regions is different. I recommend putting some of your kitty litter in a cup and adding some tap water and then testing the water for degrees of hardness and pH. My Cleveland Ohio kitty litter made my normally 6 DH water into 16-20 DH. My Winston-Salem North Carolina kitty litter makes my normally 0 DH water 0 DH.
The color of the kitty litter was gray in Cleveland http://gallery.nanfa.org/v/members/Eric ... m.jpg.html
and here's a photo of it in Winston-Salem: http://gallery.nanfa.org/v/members/Eric ... h.jpg.html
So you can see there's a big difference in what kitty litter you get based on where you buy it. But it worked for me either way. More info: http://www.thekrib.com/Plants/Fertilize ... jamie.html
"My idea was to buy some of those mini Terra cota pots that they sell at Walmart." Yeah, I've used terra cotta pots from Home Depot. I actually dropped a few on purpose to make fish caves.
"I tilted the tank at an angle and every single snail was washed out!" If you hate snails, if you keep fish that eat snails, you'll never see them. You saw my video of my tank up there; I don't really have a lot of snails. That's because along with the guppies in that tank there are Elassoma gilberti, gulf coast pygmy sunfish, which eat baby snails. Other snail eating fish include lepomis sunfish like dollar sunfish, longear sunfish, pumpkinseed sunfish, and orangespotted sunfish, darters like rainbow darters and orangethroat darters, pufferfish like malabar pea pufferes, loaches, cichlids, and the paleomonetes shrimp I used to keep ate snails too. If you have some of those fish in your tank you see much fewer snails.
"I was wondering if there was some aquarium safe paint that I could use. The clay color does not work for me." Any paint that says 'potable' means it's safe for drinking water (and therefore for the aquarium). On a kind of related subject, you can also put the kitty litter underneath your gravel. That way it's down there so the plants can reach it and find food, but the gravel's on top so what you see is your nice pretty pink color or whatever color you have. Don't be too vigorous during siphoning and the two layers will stay separate.