How much bio active substrate in a 4 foot tank?

[Shivagirl]

Hello everyone, I have a 48Lx34Dx12H enclosure for big ball python and I'm now switching him over to a bio-active substrate. I was wondering how much substrate in gallons I'll need? As well as how many isopods and springtails I will need to buy? I know what I need to purchase, just not sure on the amount hahaha
Thank you!

[MartinD]

Hello and welcome to the forum. I'm not into bio-active but there are quite a few on here who are.

[eminart]

If your enclosure is only 12" high it's going to be tough. I really wouldn't recommend less than 6" deep. At that depth, you'll need 5.67 cubic feet of substrate. But that isn't going to leave much head room for your snake. That's a rough estimate that doesn't account for your drainage layer.