Put this product in as directed and there was no change in algae.
Treated a second time and there was still no change in algae.
After a week of waiting decided to do a complete water change and clean to fix algae
I was told this would help control and hinder algae in a concrete basin water fountain. It did nothing to rid or hinder. I cannot recommend this for this kind of use. Will it work in a glass aquarium? I do not know and will not suppose.
I don't buy them for an aquarium. I find that a tablet placed in your bird baths not only keep them from turning green with algae but seems to not interfere with the bird visitation whatsoever.