I did not see a picture of your aquariums before posting my reply. Your tanks are BEAUTIFUL. I think the 15 gallon rimless might be my favorite the aquascape is amazing. The 5.5 is great as well as the tub. The live plants you have probably help with water quality too which will help out a lot! Tanks with A TON of live plants can usually go a bit longer without as many large water changes. Maybe instead of huge water changes you could start doing smaller ones more often so that it would not be hours of cleaning at a time.
29 gallon Tank inhabitants
Female Betta Pearl
Platies ( Males)- Marble, Sparkey, Glacier, and Silver.
Female Balloon Mollies- Popcorn, Licorice, and Melon Ball.
10 gallon Tank Inhabitants
Percy ( Male Betta) and Big Guy (Male Platy).