[IME what you use to test your water is one of the "you get what you pay for" items in this hobby.
For salinity/specific gravity, IMO you should get a refractometer.
For the nitrogen cycle (Ammonia, Nitrite, Nitrate) I have always used Fas/Sea Test.
For pH, a meter is best, pinpoint is almost always recommended but there are many had held to choose from.
For Alkalinity and Calcium, Salfert.
That's just my two cents. I am sure others will chime in.]