Thanks for the reply, I think my organic waste is pretty low but maybe I need to look at the flow, I have a fluval flex 34 and the flow is quite strong so I've had the outlets pointing backwards rather than across the tank.Yep that's staghorn. Only ever shows up in my tank in areas that are dirty and have poor flow.
Hydrogen Peroxide or Excel spot dosage will kill it but the avoid it you need that tank to have good water circulation and low organic waste
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