The best algae eaters are true siamese algae eaters (SAE) and oto cats, What kind of algae eater do you have? chinese and golden algae eaters are useless at algae eating. I find that oto's do a great job with algae on plant leaves, they are so small they don't do any dmge to the smaller leaved plants. Oto's also do not add much to your stock load because they are so small. 3-4 per 10 gallons will work great. Chinese and golden algae eaters become agressive when they mature and are considered semi-aggressive. They may attack the betta as well as the farawella (also not that good of an algae eater)and guppy's. Cory's do ok at cleaning up uneaten food. Do not supplement the diet of oto's or SAE's (unless you have no more algae) and they will clean up nicely.

Sorry Forgot to add, nerite snails, I am almost sure, are for salt water or at least brakish aquariums. I remember corectly in a freshwater brakish aquarium the amount o salinity that the snails need to survive will harm the plants. What type of lighting do you have, meaning tank size + color temperature or "K" rating ? Also what plants are you keeping? Do you have CO2 injection? Reason for asking a planted aquarium with more than 2 watts fluorescent per gallon usually needs CO2 supplementation or algae problems are guarenteed. Most plants do well in 2 watts per gallon (WPG) of 5500K - 10000K lighting. exceptions some swords and most red/purple leaved plants.