2-3 hours to do all my aquariums. I recently got a new 30 gallon aquarium last week so you could add 20 munites too that. I stupidly forgt to doa WC in my 65 gallon aquarium last week. Well I didn't forget I just was lazy. But I rarly forget.
4 hours or so. i change water on my 5 tanks 2-3 times a week at about 20-60% on my 240, 150, 135, 75, and 40 gallon. i use 1 1/4" hose to drain outside and fill from the faucet. with the large hose i can drian the 125 in 7 minutes