Bests & Worsts Reviews from Amazon

Definitely clears up algae, but API should really educate its customers on its "side effects". Its active ingredient is considered deadly for aquarium fish, but only above a certain concentration (look for the LD50 specification). If you dose appox 1ml per gallon, it is at approx .001 mg/l concentration, which is not fatal for 99% aquarium fish. What most people don't realize is that the after effects of any algaecide is what usually kills their fish. Think about it: algae has been in your aquarium for quite sometime right? Established itself in your tiny ecosystem? Of course killing all of the algae in your tank will have repercussions, think of it as removing all of the bacteria in your tank all at once. When the algae in the tank dies, two VERY IMPORTANT things happen: 1. ALL of the oxygen the algae was producing suddenly stops (and if the algae is bad, this is a significant amount) 2. Algae is a very simple organism, if its green water it is single cellular. So when it dies, it begins to decay IMMEDIATELY. That is why on the label it says to remove any dead algae. I know this because after adding 4/5 the recommended dose, my green water began to clear and my ammonia levels went from 0ppm to 4ppm in a matter of hours! And remember, ammonia is much more toxic at a higher Ph. Thankfully I watched my tank parameters carefully after adding Algaefix or it would have crashed the tank. If you decide to use it you absolutely should have at least: An ammonia test kit An ammonia remover EXCELLENT filtration An air pump with circulation to keep the oxygen levels from plummeting By having these things I managed to not lose a single fish, and alot of these were sensitive cories. And my snail population seems to have had no effect. tl;dr - It works but WILL cause ammonia spikes, ph crashes, and decreased oxygen levels if you're not observant!!!