Nitrates come down too fast?

[CorbetJackson50]

Ok. I learned recently my Nitrate test kit was defective.... I kept getting undetectable nitrate levels. I began to become skeptical of the results. I picked up a new test kit and low and behold Nitrates were over 100ppm! I did 5g water changes almost every day (25g system) until nitrate levels were <10ppm.

This is a zoa only tank. I noticed after a couple days some of my zoas were looking much more full and plump. However some of the zoas that looked good in the high nitrate water were closed up and some melted completely overnight!

Could the somewhat rapid decrease in nitrate cause some of my zoas to get mad and others to melt completely?

 

[Randy Holmes-Farley]

It could be a lot of things, but it is possible that it was the nitrate decline after they became accustomed to easy availability.