My experience with GC has tended to be a bit different than the norm. We bought the property in 2009 complete with nearly 30 year old pond. Among the LMB and YP there were 2 big carp, both over 25" long. There were no macrophytes nor algae visible in the pond.
After 2 years of our ownership, the pond developed a monster elodea problem. The weed covered 60% of the pond bottom. We added five 10" GC. This was before I found the PondBoss forum. I imagine we would have added many fewer in our 1/4th acre BOW had I known the recommended stocking rate.
The 6 remaining GC are all over 30" now; one is pushing 40". In 1/4th acre! If I didn't mechanically remove elodea, 100% of the pond bottom would have rooted and growing there. My observation is that the GC are cropping the plants on approximately 50% of the bottom. I rake some of the rest.
Initially our introduced GC came to hand thrown pellets each evening. For the last couple of years they seem to only cruise by once a week at feeding time.
I'm torn between removing some of the GC to reduce the biological demand and perhaps free up some carrying capacity for harvestable fish, and retaining all those big, old, non efficient weed eaters. They certainly seem to be doing some good. As my pond is small and has plenty of shoreline for carp stalking, I could shoot as many as I needed to in only a few weeks time.
