Isn't there a test kit that includes all tests?

[JammyBirch]

One suggestion I received that I will now pass on to you, don't rely on 1 test.

Here are the tests I utilize:
Calcium: Red Sea, Salifert
Alkalinity: Red Sea, Salifert, Hanna Checker
Magnesium: Red Sea, Salifert
Nitrate: Red Sea, Salifert
Phosphate: Hanna Checker, Salifert

I have at least 2 ways of testing everything so I can compare. I don't want to think my alk/calc is good only to find out later my test may have been compromised or incorrect, and I would suggest that to you as well. You can't go wrong with Red Sea/Salifert, but you definitely can't go wrong if you compare the two!

How often are you guys testing? I admit that I used to test a lot, very systematically and recorded all of my measurements religiously...in the beginning. I never double checked with another test kit...this hobby is expensive enough. Plus I learned what the tank was doing over time...I don't measure anything except Alkalinity now...