FAQ: Will the phosphate in Seachem Flourish® cause algae?

I believe if you check the amount of phosphorous content (< 0.01%) you'll see that at our recommended dosing this would only add 0.0005 mg/L (ppm) of phosphate to the water. This is completely negligible and poses absolutely no risk of algae growth. So unless you are planning on a 1,000 fold overdose you don't have to worry about ever getting any measurable phosphate from using Flourish®. We don't sell Flourish® as a macro element supplement which is why the nitrogen, phosphorous and potassium levels are as low as they are.