I need algae eaters in my 33 gal hex tall tank. I have 4 black kuhli loaches as bottom feeders and since it is a tall tank there isn't a lot of substrate surface area. My water is soft and slightly acidic. As far as I can tell snails are out because of lack of calcium. Even shrimp need calcium. Is there any feeders who eat algae off glass and ornaments who can thrive in this environment?