I have tested a gallon of muddy pond water with 1/8 tsp of gypsum. it cleared in about a week (it is still stained the color of the mud). Am going to try a 1/4 tsp just to see. My ? is there a right time of year to start trying to clear a pond? Warmer weather for better plant growth etc. I'm in SE Texas, so we're not talking extremes.