what is your PH at as low Ph is hard on those flashers and many other fish in general. It can also cause the Zoos to close up. I would get a new test kit and take a sample with pipit from the middle of the water column or center of tank water tends to be in motion there more consistently and you get a better reading. Its kind of like when you do a test on a pool you are suppose to take the sample from a bout 2-3 feet below the surface and around the middle of the pool to get the most accurate test results.

Bill