test kit question
 

can i use a hot tub test kit for a substatute tank water kit? i dont know if a hot tub has amonia or nitrates or nitrites

What parameters does it test? I would just stick with the API Master test kit. It has over 700 tests.

Only for alkalinity, pH, hardness, and chlorine (I used to have a pool).

API Master test kit is the best for aquariums. I would stick with that since it has what you'll really need (Nitrites Nitrates Ammonia). But if you want to test any of the above, I don't see why not. It's the same story though, the liquid tests for pools and hot tubs work much better than the strips.