DE escaping from the filter into the pool...

[wen95070]

Hi SS, I have an old Pac Fab (PENTAIR) FNS Plus DE Pool Filter. The manifold does sit on top of the array of grids. However, I always remove the manifold and pull the grids out separately to clean. I have inspected the grids, manifold, manifold O-rings, and even the air bleeder (air relief tube?). None seem compromised.

I am, however, headed down your path. As I alluded to earlier, the only question is, will I replace individual field-replaceable units (e.g., grids for ~$200), the whole grid subassembly ~$400, or will I just swap the whole unit for a new DE or cartridge filter for ~$1,000. I am very curious about the new cartridge filters that are supposedly long lived and low maintenance.

Did you replace the grids because you actually found the tear(s)/leak(s), assumed them to be the most likely culprits, or wanted to eliminate them as a possibility?

[waste]

Wen, Scott, (welcome Scott, good choice comming here instead of being 'POOL STORED'), not only is getting the grids to fit in the upper manifold a hastle, if they don't all fit in tightly, de can pass through the gaps, and if that o-ring on the shaft that the manifold sits on is gone or compromised - de will go back into the pool. Another way for the de to enter the pool is by a bad seal in the multiport - in this case it only happens when adding the de, it slips by the gasket and some of it ends up in the pool. Yet another way is to have the pump pushing too much water through the filter for the filter to handle (somethings gotta give ). I'm trying to give the complete scenario. I, personally, prefer sand filters, but they don't clean as well as the others - though they are easiest to maintain. I don't want to tell either of you to replace the whole filter, but if you find you need to, get one with a multiport, you'll thank me. Any questions? - just post and I'll get back to you

[wen95070]

I hypothesized that the DE around a hole in the fabric would show signs of erosion. So, without rinsing off the DE from the grids, I disassembled and examined each panel. As I found these eroded patches, I marked them with a Sharpie.

When I finished searching, I risnsed off the grids, leaving just the demarcations (around holes of varying sizes and shapes.) The air bleeder was in the worst condition, a 1/4" opening at the tip.

I checked and relubricated the O-rings. Then, I sewed up the air bleeder and patched the grids with low-temperature hot melt glue. The MSDS claims that the glue has very low water solubility/ extractives and is stable at pool water temperatures.

When I reassembled the grids, I noticed some of them no longer seated perfectly against the manifold because their frames were cracked. But I figured to get one more season from them before buying a new set.

After vacuuming up the DEbris (sic) at the bottom, I ran the pool pump/filter for several hours with no detectable DE in the pool/spa. I had almost forgotten what "polished" looked like.

Waste, Thanks for your advice and support.

[ScottsdaleSwim]

wen- glad to hear you solved your problem! I received the new air bleed screen and it's just that- screen. The old one was a fabric of some sort. I still haven't installed the new one. I need to drain a little anyway as my cya is off the chart.

Getting those grids into the manifold is tricky and frustrating at times. We replaced the grids because we found a tear in one and a crack in the end that goes right into the manifold. I purchased mine online for 108.00 but I have a 36 sq ft filter area.
Much cheaper than buying them locally.

I'm hoping the new strainer will work and completely clear it. The little bit of DE settles into the liner creases and drives me batty.

[wen95070]

[...deleted] Much cheaper than buying them locally.

About 50% cheaper even with S&H. Good luck with your DE filter. With my DE problem addressed, I am observing my Polaris, which lingers in the northern corner of my pool .