Who Gives A Fish Forums

I disagree with the RO water suggestion. Unless your tap water is terrible, it's unnecessary. Just age it for 24 hours to off-gas chlorine. Stability matters more than chasing 'perfect' params.

Vallisneria requires stable conditions. If you're new, Hornwort's the safer bet. It's less likely to die on you while you learn the ropes.

I use pool filter sand in my tanks and it's been a game-changer. No issues with clogging or anything. Got a great deal on it too - 50lbs for just 14 bucks. I've got a 55g tank with the mystic white stuff and a 20g with the light brown kind. Looks pretty good, if I do say so myself. Plus, cleaning is ...

A pair of Kribensis could work well in a 20g, but you mentioned wanting a species where you could keep more than a pair. If you're open to shell dwellers, I've had some experience with them.