I've used it before with some of my previous reptiles and so far, so good. My reptiles were healthy and showed no signs of problems. I read that it reduces pH, removes chlorine & ammonia, and adds electrolytes - so what I did was get a used water bottle that I drank from, filled it with tap water, and followed the instructions (2 drops per 8 oz & 1 tsp per gallon of H2O). I shook up the bottle, let it sit for a few hours, then added it to water bowls and the toads' pond area.
It's worked for me before, assuming that the reptisafe is doing what it's supposed to. I say this because I haven't used it at all with my current leopard gecko (Currently, she's just getting bottled water) and she's also active and very healthy.
I bought it just to try. I use bottled water and tap water without adding something and everything looks fine. Is just that I have very sick gecko and I want to try reptisafe, maybe it'll help him somehow...