I hope she is using a water conditoner, like prime ar aquasafe.she is on well water so i don't think chlorine is an issue
OH NO! 50% EVERY WEEK!50% water changes every couple weeks.
Is she testing the water? Ammonia, nitrites, nitrates? This is very important.
The water probably is cloudy from any combo of the following-
a: Bacterial bloom/un-cycled tank
b: the huge amount of waste those fish will produce in a 20g
c: lack of proper water changes