2.5 gallon and 10 gallons of water change a week is not a lot.
Fish/inverts are fine, I have 1000 RCS, some a really super blood reds, cards and many other so called sensitive fish.
You cannot over do water changes really.
They will only help, but at some point, doing more really does not help.
Dosing is not everything, light and CO2 are more prominent if algae and plant health, nutrients are rather easy and simple to rule out as possible issues.
Get light/CO2 in line, then you can manipulate the nutrients and see much better the effects.
I might add the 13.8 % chelate, say 1 teaspoon to each table spoon of CMS+B mix.
What type of chelate is it?
I do up to 80% without issues, never had any water change related issues for that matter other than perhaps a lack of them.......