Mike, If your pond was 100% covered last year the addition of dye will (at best) slow up your algae but will still come. Consider looking into where your nutrient load is coming from and reducing it instead. The lack of sun light will also slow up 02 production.(not good) Normally the more dye in a pond the lower the potential for o2 production thus making proper aeration even more important.Your water temp is still very low and when it warms up your algae will be there. What is your water source and what fish have you stocked and what
do you do for aeration.Ted PS Welcome to PondBoss !!