should I just pack it in???

[Willito]

Man I don't know how you've done it for so long without an RO/DI unit. The corals live and breath through their surrounding, I bet you it's the main cause of all your problems. With the spring run-offs lately, the water is full of inpurities and that can reek major havoc. Get on one of those units right away.

Downsizing won't make you happy, downsizing the content may. The way your tank looks right now, with that many corals, you are bound to reach a point where you will have to get rid of some. There just won't be enought room for all to grow.