Re: 6ft./150 gal first time Palu build...
I could not tell you why algae grows on it. My whole point was be sure what you're putting in your viv. I know for a fact EPDM liners are safe. If pool liners are then why aren't they used in ponds? I'd rather have the OP make sure it's safe rather than to just assume it is and end up disappointed with dead frogs. It's worth checking out just to be sure.