Hi, bear,

Yeah, the issue is interesting to me, too. Let me say, first of all, that I've got a big sand filter and my water is pristine....I couldn't imagine it could be improved.....naturally, it follows I am a big advocate of sand.

I'm not sure I agree with this but the thinking of others on the forum is that, as the sand captures smaller particles, it captures smaller and smaller particles as they accumulate. If so, then it would seem backwashing would eliminate any temporary advantage.

Your thought of the "rounding off" of the sand particle might likewise have some merit. However, might not the rounded particles "fit" tighter together allowing them to capture smaller particles?

My thinking about channeling is that it's caused by the filter being undersized causing the water to pass through the filter at an excessive velocity.

So, since I can't come to a logical conclusion that changing the sand will provide a benefit I can see or understand, I plan on leaving mine in there.

I have no idea if my thought process is correct or if any of this matters a hill of beans to anyone but it's too dark to go outside and mess with the pool and there's never anything decent on TV.

Dave S.