I keep everything. Clams, SPS, LPS, Softies, Zoas, Palys, Chalice, Brains and Rics, ect.... My tank is a 90 AGA with offset overflow. Sorry for being general.....
Anytime flow is reduced then your leaving water quality open for trouble.It could take awile to show and this can leave you to believe its from something other then the lack of flow over time. Then you end up buying some addon to help control and find it doesnt cure the problem.
If you have lots of stock then reduceing for an hour or 2 to allow them to get a better meal. But there are many factors. And if flow amount drops to low then you could wake up to dead and or deing fish.
Once you have flow properly tuned then its best to leave it be.