Every Friday I buy 2 five gallon jugs of DI water, come home and mix the salt into one of them. Drop in a power head and let it start mixing. I don't add a heater but I do put it in the warmest room in my house. On Sunday morning, I pull 5g's out and put 5g's of the salt mix back in. I use a 1 gallon pitcher and put it back in so that it doesn't splash all over the place.
The other 5g DI water is for top off from evaporation.
Clean. Easy. EVERY Week.