I haven seen any ill effects from adding home grown phyto to my tanks, but i dose sparingly, how long are you culturing your phyto for, i leave my for 14 days, most recommend 10 but im using lower lighting, and the colour still darkens at around 12-13 days. I think the most important thing is harvesting time, to make sure that your phyto actually absorbs the f2 in the water, so that you are not dosing your tanks with phyto and f2.