1/4 ac pond will need 10#, 1/3 ac pond will need 13-14 pounds of Tilapia for them to work. Water less than 24" deep treat with Cutrine Plus liquid +-5 days of stocking the Tilapia, water that is deeper than 24" and has algae growing in it treat it with Cutrine Plus granules. Follow the label for proper application rate. The trout might croak when using it, they are very sensitive to copper.

If you don't kill the algae when the tilapia are stocked, you will be lucky if they work for ya. I've seen a 1 ac pond stocked with 100# of Tilapia without the algae being killed and it looked like they didn't do a dang thing. Stocking rates up here for them to work is 40#/surface acre. Ask them what ratio is the male/females in the tank, and ask them if they are hybrid Tilapia or pure blues. I have never seen a pure blue tilapia any color other than steel blue in color.

Maybe Rex can chime in? He knows more about them than I do.