What are your TDS readings?

[RockyMtnReef]

Curious if you guys measure TDS and if so what is considered ok for a FOWLR?

[Zoodiver]

Read TDS of your top off fresh water. For a reef, should be zero. For a well established FOWLR tank, it can be higher - though most will suggest keeping it as low as possible.
Trying to read TDS in saltwater will really jack up your probe.

[Dmorty217]

^+1 as close to zero as possible is best for all saltwater tanks

[RockyMtnReef]

I used tap water with a TDS reading of 55 ppm to fill my new tank. I was planning to use RO/DI for top off and water changes going forward. Any potential issues?

[Zoodiver]

I use/have used dechlorinated tap water in many marine systems over the years.
You may have a little algae at first if anything (depending on your source water), but nothing too bad for the fish.