So I want to start with thank you for responding so quickly.
Yes I moved from one apartment to another. So my P. Filamentous are in their same tank. When I got these fish I chose to buy their entire set up, tank, substrate, filter that they’d lived in for about a year. New home equals new water. No I’ve not used RO water, I use my tap water and usually treat with Seachem Prime or API Tap Water Conditioner.
As for water changes weekly is the norm, I do small changes due to how sensitive they are. I do gravel vacuum, this is a species only tank. They have drift wood, plants with fluval stratum (I think that’s the name of the substrate) I use a sponge filter. I don’t know the last time I squeezed it out, it may have been when I moved.