I would suggest that if your water has high phosphates and that this is causing your algae problem then you might need a longer term solution. You could consider a UV
filter which, if the right wattage and water flow is maintained, would also give added protection from bacteria, fungal spores and reduce the efficiency of parasites such as ich. There are a few cheaper UV
filters that are effective against algae but don't also protect against 'nasties'. But my thinking is that if you go to the trouble of installing a UV
filter then a little extra cost could bring greater benefits than just controlling algae. It's just a consideration.
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