I suggest maintaining a small amount of salt in the tank, it combats nitrite toxicity which will keep the fish safe, and it only takes a tiny little bit. It's not enough to hurt the fish or plants by far. In a small tank I'd probably just put a pinch in there, as there is likely some present in the tap water to begin with.
I have a question about RO though! I was told if have to add minerals and what not to get the levels in the water I want is this true? Or is ro water ready to use. I just recently was informed about ro and have no experience with it
I'm not sure where to tell you to look but honestly on-line will not only give you the biggest variety but also the best prices even if you have to pay shipping. I've head of some people talk about water filters that can be added to a faucet that removes some things "similar" to RO but unless you can get info that they would actually remove ammonia in your case I wouldn't get one.
Can I wait about an hr before doing another water change? Or will that be too soon for them?