First off, the apple snails are tropical but they are most active at temps of 74F-80F, but will still be fine at 70F and up. Anything lower than 65F and they will perish, and the higher the temps the faster they grow and it will shorten their lifespan. So 78F is fine or even a bit lower.
Second question, "too" is used for also "They are funny too" or as a higher definition, as in "The snails are hysterical too". With the three words, to, two, and too, the first is like a location, "going to church", the second is a number, "The two of us are going to church", and the third is like a qualifier, "The two of us are going to church too". Hope that helps