Best way to check water parameters
I just tested my tank water because I have lost 4 rainbow shrimp since Friday. I test my water with the API Freshwater Master Test Kit (liquid test). I test gH & kH with API 5-in-1 test strips (getting liquid test kit soon). I've been running my 75 gallon planted tank for about 5 months now & am really starting to question if my test kit is accurate. The reason I wonder is.....from day one of my set up, I have never registered any ammonia or nitrites, and today is the first time I have ever registered nitrates on this test. The nitrates showed to be a shade in between the 0 range and the 5 range. I'm guessing that this (not registering any parameters) is uncommon....seems that way to me.
Is this the best kit on the market....or is there a better way to test my tank water? What do you guys use?