Agreed.exactly, its like keeping a hamster in a packed lunch box... a big male jag needs a 180g imo.
I've been doing 80% weekly of late to try get my gt growing a bit quicker, the more the better. I remember when I used to have discus reading about breeders and professional keepers doing 80-90% per day and how they had never even had to cycle a tank before and had never seen such good growth. Can never do too many, just depends on how big you want your water bill to be lol.How often do you guys do these 90% changes?