First off, cool solution. I just use something like this since I mainly fill 5 gal buckets. I also have a flood alarm sensor I use as a backup.

Neat! I haven't seen these, but it would be a good option under different circumstances.

you'd just add another step at the end with a remineralization cartridge like this.

Once again, good to know. I wasn't aware of these, and had actually been looking at "remineralization drops" which could be added manually. I also read about others adding Himalayan salt.

I bought the system with DI filter because I thought it might be useful for cleaning electronics. It's not something I'm likely to do a lot of. Taking your advice, I think I'll run the jug-filler line between those stages. It hadn't actually occurred to me that I could until you mentioned it.

Regarding the fluoride, I didn't find an equivalent refluoridation cartridge. Although there appears to be tablets that can be taken like a vitamin supplement. Maybe I'll just use more mouthwash for the time being.

For TDS meters I've owned several cheap ones from Amazon and they all worked well enough. I recently switched to an inline one like this though. I'd personally recommend it for convenience.

I'll taking some direction here too. I think I saw an image of that one on Amazon but skimmed over it, not realizing it's in-line. That is convenient! I was really on selecting the other because someone mentioned getting an HM one with temperature sensing, that being a preferred model.

I'll be getting this one https://www.amazon.com/Commercial-In-Line-Dual-TDS-Monitor/dp/B000VVYRVQ for the use of AA batteries vs coin cell, and the ability to calibrate.

Thank you! Glad I didn't hit order already!