Stoned, some people use tap with great success. When I used it, although params read fine, the shrimp would die off...until I changed to all RO.
Challenge is tap conditions can change season to season and in a heartbeat. We do a bunch of tests on water, but we don't test for everything.
Have you thought about RO with remin? It may help with survival. IN this case, it would be fairly simple to do a water reset, provided you have the remin product already.