1.I conducted a test over the past three weeks on my Pentair FNS Plus 48 DE Filter trying to eliminate the clumping and grid coverage issues that I talked about in an earlier post. I added the filter media as directed on the packaging - 3 cups per 12 feet of filtering area slowly through the skimmer, I let it run for a week then pulled the grid assembly. There was filter media all clumped underneath the grid manifold and did not evenly disperse throughout the filter grids.
2. The second test I added the filter media as a slurry through the skimmer, let in run for a week, pulled the filter grid assembly, although their was some clumping at the top of the filter grids it wasn't as much as the first test and the distribution of the filter media, though not full coverage on the grids, was better.
3. My final test, I dissolved the filter media, added it through the skimmer, and again let t run for a week, pulled the filter grid assembly and there was no clumping anywhere on the filter grids and the coverage, again not complete but was the best of the tests. I don't know if I am the only one having the filter media clumping (or building up) on the upper portions of the grid assembly, but it seems dissolving the filter media gives my better filter coverage and no clumping.
4. There is one thing I noticed out of all three of the tests is that the air bleed tube that attaches to the top of the filter manifold becomes clogged with filter media, so after a day a running the filter I remove the lid, clean the screen on the air bleed tube. Don't know if this is normal as I could not find any information on it and nothing in the owners manual either.