That depends on how many treatments you have done. For problem algae, you want to treat every three days for up to three treatments. If you have done all three treatments, you have one of two issues going on. You could have very soft water, in which case, the product will not be as effective and you may want to do a water change, and add some buffer, then try another round of treatments.
However, from your description, I suspect you have cyanobacteria. This is only affected by erthromycin, and you would need to treat with this antibiotic to get rid of the red "algae".
answered 1 week, 6 days ago
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