Well... with just under 90 tanks and some using up to three air stones each. I just want to try a passive way to get a second or third use out of them, but I don't want to have to hand clean each one. You're right Ron, time is important.
Muriatic acid had crossed my mind, but didn't know if it would be too harsh.
I do buy the 100 pack of ceramic (or glass) at Kens for $19.95. Cheapest I've found.
As far as plastic ones. I've tried them and they seem to clog quicker that the glass/ceramic. Don't know if the pores are smaller, but I seemed to get about half the life of a glass/ceramic one.
I've also tried without an air stone and won't do that again.
Well, I let them soak in vinegar for 24 hours, then rinsed real well, now letting them dry. We'll see how it works.
Thanks for the input.