In reply to Adam …. The API tests are reasonably accurate. Your water supplier may be adding hardness to the water in order to stabilize the chlorine additions. In any case the water will be just fine for angelfish and tetras.

And the fish photos are from the internet.

I bought an API hardness test kit. I followed the directions precisely. According to these tests, my tap water is very hard; 13 drops for GH and 10 drops for KH. This is African Cichlid hardness, right out of the tap. My wife wants to get angelfish and tetras. I am worried that I will need to get a RO filter for these softer water fish.

However, the test results don’t make sense to me. I live in a part of east Texas not known for having especially hard water (my municipal water comes from a river, not an aquifer). I don’t have any hard water marks on my faucets or shower doors.

In your opinion, how accurate are these API hardness test kits?

P.S.: I love the fish photos sprinkled throughout the book. Are they from your tanks?