I've never actually used any regulators or chemicals to help the water quality. In general it sounds like you shouldn't rely on them. You really, really should get a testing kit, though. They can be a bit pricey but they're definitely worth it. If nothing else at least get one for ammonia. I prefer the full ensemble, though (ammonia, nitrite, nitrate, and pH. Water hardness too, if you're lucky).
Given the current parameters I assume the tank isn't cycled? Do you know about cycling? In essence, just test the water daily and do daily 20% water changes until the ammonia and nitrite are both at 0 (or very, very close). Once it stabilizes you can safely do weekly water changes. You basically just need to build up the bacteria necessary for breaking down the toxins in the water. Once they're established you don't need to worry too much, but until then the water can get toxic quickly.
Good luck!