oh.... I know many experienced aquarist say they only breed according to the amount of food fed to the fish. Not true in my experience. These things continue to breed and it is my opinion that I see them at all hours because there isn't enough food for them so they are constantly searching, stealing food from my fish.....
Two good points on the topic.
1st - Food source.
This is often misquoted/misunderstood. It's not about really about adding flake food, it's about TOTAL FOOD SOURCE
. Food is a limiting factor in reproduction for all living things. So it's not just left over flakes, it's algae, dead plant material, detritus, etc.
2nd - Population control.
I think a indicator of when to cull is when they start breaking their natural cycle of being buried during the day, out in the open at night.
I look at my Ramshorns and MTS as algae management tools. Just as water changes and pruning are a regular part of maintenance so is culling snails.