I bought the freshwater master test kit by aquarium pharmaceuticals,inc.Its a liquid test kit covering ph ammonia nitrite and nitrate.Is quite expensive but lasts ages and is cheaper in the long run.Liquid test kits are IMO far more accurate and cost effective than the strip ones.The downside is that mine was £24odd.Keep an eye out on e bay.I got a 2nd one covering gh/kh etc for £15