yeah i mean they suck, i got 3 adult snails a couple months ago but got rid of them and i still have a couple babies that pop up here and there but nothing to bad, i could understand not wanting to risk it but think about it, were you overfeeding or something when this happened? i guarantee there will only be the number of snails that there is food for, they overpopulate and run out of food then they die off from starvation so only number that can sustain from extra food in tank will thrive, its the same with algae if you dont have extra nutrients in your water or too much light then algae will not grow, as long as you keep everything clean then nothing should get out of hand but yeah as long as he doesnt eat the shrimp then they should work as clean up crew