I use RO/DI for the same reason Blue Ridge Reef does, left over from when I used to keep reef tanks.
I've been remineralizing with GH Booster and using potassium bicarbonate to bump up to 1 dKH or so (6g to 30 gallons of water). I use aquasoil.
Now I'm wondering if I should cut out the potassium bicarbonate. I was worried about having too low of a pH (it was below 6), but I'm keeping tetras and corys so thinking I should be fine with a pH in the 5's.
I'm also concerned about the issues with using DI (mixed bed cartridges) and potential pH swings as filter starts to get exhausted. My system has goes sediment cartridges ->carbon block -> RO membrane -> first DI cart -> second DI cart -> final product.
Should I figure out how to reroute the flow of the RO and replace the DI carts with additional sediment and carbon blocks, or just remove the DI carts? Is it worth the effort or should I just continue with RO/DI?