GDominy, I know that when Melanoides snails multiply like that it can be hair-raising, but here's another way to think about what was happening with snails in your filter.
Think of all the nutrients that would have been in the filter were transformed into snail tissue, snail shell and snail metabolism, especially the nitrogen,and phosphates. If they had not been transformed into Snail, they would have been broken down by bacterial action, "mineralized", and thus made available to algae once more-- and plants, too, of course.
The shells are made of calcium carbonate and some magnesium too, as "apatite." That Ca and Mg came directly out of the water, where it was contributing in its small way to your KH.
And further, it's been shown that bacterial action is stronge, bacterial communities healthier and more diverse,r where the bacteria mat is being grazed.
They may have freaked you, but they were making a wholesome contribution by interrupting the nutrient cycles that feed algae.
Thank you for the welcome and I was searching for snail info. lol
