[Delphinus]

But the height above the overflow is a function of the water pressure from the sump return. It doesn't take much of a throttle adjustment to lower a water level 1/4". I know this because that's how I solved MY salt creep problem on my 72g. Exact same problem, little waves would sometimes splash into the tracking or whatever that plastic rim thing is called, and I'd have salt creeping down the front glass. I'd clean it up, and it would return 5 minutes later. I started going on about how to fix this, and I was envisioning the silicone in the track on the inside and all that, and I was all full of despair and expletives, and finally I decided to try throttling back and lo and behold it was all that was required. I don't think your water level should be right at the top of the glass. I think, and this is only my opinion I'm sure everyone else has their own, but I think that water should be down from the top edge of the glass by at least 1/2" for this exact reasoning. My $0.02 ...

I only suggest it just in case it hasn't already been considered. The elegant solution is the simple solution, and sometimes we don't see the simple solution right in front of our noses. If it's been considered or tried, well, no harm done then. Better than, say, risking spilling an oil based sealant (or paint, hmmmm?) into one's tank!!!!!!!!!!!! :P :P :P

One last thought: if it were me, and the sump return couldn't be throttled back ... I'd be looking at making my notches bigger in my overflows, or perhaps just some of them. If the overflows are acrylic or plastic, it'd be not a lot of effort. If they are glass, well it's not quite as trivial but basically the same principle, you'd just have to use a dremel and the appropriate bit (with the water level lowered a good 6"-12" of course!!!) (And for the love of Pete don't drop the dremel and use a GFCI and all that....)