Blagdon 1000ml Green Away Pond TreatmentGreen water isn't a good look for aquariums. It doesn't only look horrible, it's really bad for your fish too. Excessive light or nutrients can trigger this ugly and potentially dangerous algal bloom in your aquarium which can affect oxygen and pH levels. This makes the water highly alkaline and potentially dangerous for your fish. But help is at hand. Green Away neatly clumps the suspended algal particles so they can be trapped by your filter or sink