Using spring or tap water added back into the tank to refill evaporation, tends to lead to high TDS / total dissolved solids. A higher TDS can cause problems in a shrimp tank. I use tap water often but our GH is fairly low and KH is 0 where I actually need to add some calcium minerals.
If you already know this good (offering the additional info just in case someone else may have a similar experience and reads this later), but I didn't realize myself and how much it really adds up over time...
The water in the tank has minerals and dissolved solids, the evaporated water disappears from the tank leaving a more concentrated level of these things.
Think of a leftover coffee, tea or cola cup which dries out and has a film of rings, particles, color left in the cup.
So for evaporated water replacement, the more often you have added tap or spring water back in, the higher the TDS gets.
In a tank with shrimp, they prefer smaller water changes to keep the water parameters as even and similar as possible. This frequently creates a water volume change / pwc, much less than my evaporation. Resulting in compounding and higher TDS.
If you have the issue of high TDS out of the tap it of course happens more quickly.
If this may have happened in your tank, changing this problem, needs to be done gradually as to not stress / shock the shrimp / fish.
To remedy this issue, you can easily jump up the water changes to 5% every day to start for a few days to a week, and then up a little more maybe 5% am & pm. Making sure to keep the water temp similar as possible.
Most fish would be a little less delicate, shrimp very much prefer ideal water parameters without drastic/significant changes.
If you have a TDS meter you can see somewhat how it is helping.
As a side note though, TDS will measure all the things added. Like the water conditioner added, and the bacteria too, salt if you add that, other minerals or anything really you add other than RO or distilled water.