Only way to totally get rid of them is to restart the tank and nuke it with bleach or something. You can control them by not overfeeding and remove or crush everyone you see.
Assassins don't eat MTSnails?It's hard to tell from the pic, what kind of snails are you having problems with? As long as it's not Malaysian trumpet snails, you won't have to nuke the tank. Assassin snails can eradicate the tank of the other snails.
However, you're going to need a lot of assassins to eat them faster than they can multiply. You can help by physically removing as many snails as you can and the assassins can work at getting the rest.
They do, but because MTS bury themselves inside the substrate, the assassins can never get to them faster than they can reproduce. Assassins will go into the substrate, but not as deep as MTS. Plus, MTS get into the plumbing and filtration. I had baby MTS in the motor of my canisters and inside my uv sterilizers. No other snail does that, only MTS. The only way to eradicate a tank of MTS is to toss the substrate, bleach the entire system, and start over from scratch.Assassins don't eat MTSnails?