I can't find a smiley that conveys *smacks self really hard on head* so here goes...... I've just realised that the MgSO4 solution that I've been dosing for 3 weeks was 6 times stronger than I had thought it was. I've been dosing to 30ppm every second day instead of my aimed-for 5ppm. As per my earlier thread I've also been fighting a losing battle with BBA, GSA, and (I think) Staghorn. Would anyone care to advise me if there is a connection between my mis-calculation and my algae crop?