i want to test my calcium, PH...wat is the good brand of test kit should i buy?

salifert.

API, Elos, Salifert, and Lamotte. For things like pH, ammonia, nitrite, and nitrate, you don't need to have extremely accurate tests. API is good for the price. The other three are more expensive but also more accurate and precise.

Chinese kids seem to the best kind

My grand-kid is pretty good about testing stuff!!