70 for any size of RBTA is well worth it, and people saing the size of the fish hosting it matters, it dose not, as long as the BTA is healthy and dosent have a foot problem then its a still IMO
look in my avatar and see them maroons, the MALE is in it, in that pic and hes 4.5-4.75" big.....thats my RBTA that always splits and they like that one the most...i have bigger ones but they just like that one i guess becuase its in a dark spot...and remember maroons are some of the roughest hosters they have been hosting that RBTA for years! and he hasnt bother it one bit other then the fact that they over feed it IMO, but they know whats best for it