I'm familiar with all of those products except the Waterlife. The Waterlife website did not state the ingredients, something I am always quite wary of. I don't trust products that don't state ingredients up front and/or make it hard to find out. So I did some research and it seems it is a combination of malachite green, formalin, and acriflavine, but I have no way to verify this. Malachite green has some antibacterial, anti fungal and anti parasitic properties, but is deactivated by light, so unless you're keeping the tank completely in the dark, it's unlikely to have much benefit. Acriflavine is anti fungal, and formalin has some effect against bacteria and parasites. It might help, but only if everything else in the tank is in good shape.
It states that it "lowers the count of harmful bacteria in aquarium water". It does not state by how much, though. A FAR better and cheaper way to accomplish this is to simply do large regular water changes. I also note the wording here - "in the water" vs. the bacteria infecting the fish itself. If someone has, say, pneumonia, adding a hepa filter will keep the air cleaner, but will do nothing to cure the infection.
Snails in the filter are only going to impede the water flow, and it's not a powerful enough filter to begin with, so that's a problem for sure. Snails also add to an already way-too-high bio load.
Every creature in your tank is stressed. Except the parasites and bacteria - they're having a field day because these are the exactly conditions they thrive in. Chip is showing symptoms because he's the weakest one. If conditions don't improve, they will eventually all be like that.