Bill, thank you for taking the time for the 'big answer'.
Your 3" rock layer will not prevent weed growth. Time will prove this. You are already having serious FA issues. With trout you have to be very careful using anything with copper as an active ingredient ESPECIALLY if your water has low alkalinity(hardness) less than 50mg/L. Trout are very sensitive to copper in softer water. Are the trout still eating pellets in the warm temperatures?
Have you measured the water temps at 7ft and the bottom?
Any well water inflow?
Our water is pretty hard, 10 grains. I have never fed the trout. In the spring they were having a heyday leaping out of the water for mayflies, etc, looked very healthy, almost kind of fat. Since it got hot I have not seen much activity, but then the FA is full of bugs so they may be feeding below the surface. I don't have the bottom temps but I can get them for you. No well water flow yet, I've been waiting for the water level to drop. We were almost 2' above full pool after the spring melt.
I see that Aquasphere from Healthy Ponds is a bacterial enzyme blend. Why are you not using it again?
I am. I added a new Aquasphere just before I left, so there was a fresh ball in there while the FA was going crazy. This led me to believe that it didn't work with FA. Same with the Pond Clear, I gave it over a week and see no reduction in the FA growth rate.
Fathead minnows will not eat FA to any noticeable degree.
I just got off the phone with an approved Montana hatchery. They recommended 50 dozen FHM for 1/3 acre. They said they would be slow to start but would make a big impact next season??? (he did mention that he is primarily in the bait business, not ponds) Cancel the order?
Blue pond dye will help reduce some FA growth in deeper water depending on darkness of the blue and type(brand) of dye.
Any that you recommend? I would prefer to avoid the fake blue color.
For a noncopper algaecide control of FA, I would always first remove as much FA biomass as possible then I would try using Phycomycin or Green Clean Pro (peroxygen). It works best as hand spread granules when FA is small,short or in early growth on the bottom. Once the FA gets on top it is usually too advanced for peroxygen products unless a lot of material is used. Then you almost have to resort to using Cutrine Plus (copper product) liquid or granules depending on location and type of the algae. For trout ponds treat only small areas at a time 20-30 ft sections to minimize trout kills.
OK, I've seen Green Clean. I have no heartburn physically removing the FA. We've already done it once, I just don't want to spend the whole summer wrestling with green slime. So you recommend removing the FA, then hitting the affected zones with Green Clean, then do I come back with Aquafix bacteria?
FA will be a constant problem in a pond water trout raising operation. One thing that will help reduce some FA is to not have too many trout in the pond - lower density results in less feeding and manure and FA.
How about if I'm not feeding? Also, my population seems to be pretty steady. Everyone expected a big loss from predators, but I've only seen 1 bald eagle and 1 osprey, and the eagle left without getting a fish (the osprey tried but missed I think). Is ~50 fish too many for 1/3 acre?
