Ben had posted above about coating the filter::: Using 3oz per sq ft of sand surface... with my small 166 filter, Im putting in 4.5 ounces..WAY MORE than the 1/2 cup from the DE "thread." I backwash once the return loses most or all of its pressure... for me, that is a 6 pound rise... Just checked this morning, and this method is definitely working.... May be a slower than normal process, but like yourself, I am optimistic about this !!
I'll spend the day today hanging at the pool, and doing the backwash-- dosing "thing"... Hopefully tomorrow I'll see a little more than just my reflection when looking into the water !! : > LOL