Well, you are all making me think a lot . . .
The pH problem is
in all 3 tanks. I don't know how long it takes the tap water to drop from 7.6 to 6.0, I'll need to check that.
I vacuum the 10 and 20 gal
tanks weekly with about 3 - 5 gal
of water removed and replaced at that time. It would be no major problem to increase the amount of water.
The 55 gal
I vacuum 2x/week, taking maybe 5 - 7 gal
of water out and then replacing it.
All 3 plecos (1 per tank) have nicely rounded bellies, so I don't think they are short on food.
I do add salt to all tanks, carefully following directions and erroring on the side of too little if there is any question of amount. If I don't have salt available (for some odd reason), then I use APIs StressCoat+
All tanks have this green plant in them. It does grow, although it is not rooted in gravel. I have never been advised by local Pet shop/aquaria shop people to use CO2
. How is that done?
All of these responses have made me realize that I haven't been very scientific in my approach to the aquaria. I'll need to change that.