What is considered normal for an overnight FC drop? I am trying to eliminate mustard algae as a problem and tested my water last night and again this morning. I tested last night(more than once) and got 4.5 and 5 in 2 different tests. This morning I am getting 4 and 4.5 in 3 different tests. Looks like I have lost .5ppm FC and possibly up to 1 ppm but not more than 1ppm. I was hoping for no loss at all. Is this drop normal?
Normal FC drop overnight?
- Thread starter budysr
- Start date
Ideally there shouldn't be any overnight drop. But the test is +-0.5, so the total error on two tests can be up to 1.0 and still be normal. However, mustard algae in particular can have very low FC loss overnight, so a loss of 1.0 could be mustard algae. The only way to be really sure is to do the test again using the test that measures by 0.2.