We had the same thing happen to us. We had two out of three (constructed in Jan) go dry after filling up. I had stocked them in April with CxB Cats, M.Til, CNBG, and FHM's all from Kenneth Henneke fish hatchery. The tank that didn't go dry produced great spawns though and yesterday I siened and restocked the other two from the one. I also purchased two adult F1 LMB to clean up the thousands of tilapia. I started with seven in each tank and with no predation, they were over-successful. I will restock them next year too. What a great forage base!
I am an aquarist so I will pull some out and overwinter in heated fish tanks before they all die in the winter. I don't think there's a downside to using tilapia except the only way I can catch them is with a cast net. They keep the algae down, they reproduce unlike anything I've ever seen, and they are shiny white fish that bass can see well. The hybrid cats also were impressive. Some only seemed to double in size while others exploded in size. In April, they were 2" and now most are probably 18" and nearly eating size.
I had been fighting the evaporation loss with a garden hose, but that proved futile when I calculated the evap loss at more than 1000 gal's a day in June, July and August. You just can't replace that. You can only hope that you get a wet winter and spring to fill them up.
I feed heavily until the water temp hits 95. I guess that explains the explosive population growth. Since I am about 60 miles East of you, we face the same issues and I'd be happy to share any hard-learned lessons with you if you have any questions.
