Hayward Diatomaceous Earth Filter - Earth in Pool?

Question

We have had our pool for 11 years, but this year has been the most challenging for my husband and the pool. It took forever to get the levels right, but the pool is VERY cloudy. He's been backwashing regularly to get the pool clear, but he went into the filter the other day and there was no earth in it - light bulb moment - that's the film we are feeling on the bottom of the pool!

So what is causing the earth to enter the pool - and where is it entering from?

We just don't get this at all.

Thanks so much for your assistance.

Answer 1

We just installed an in-ground pool and spa with a DE filtration system. I have noticed that when the system is started each day, a light cloud of DE is emitted from of the return lines in the pool and spa.  It happens for a about a minute, then the water is clear and there is no further emission.  Our filter is the Pentair Quad DE system, which is a cartridge-based DE system.  Since it is new equipment, it was hard to believe that there were rips or tears or holes in the cartridge, cracks in the manifold or other issues.  We did a complete teardown and cleaning of the filter, made sure every last spec of DE was rinsed off the cartridges, inspected for cartridge membrane defects (found none) and put everything back together according to the manufacturer’s instructions.  Turned on the system and we’re still seeing a brief cloud of DE entering from the return lines, for less that one minute and then the water is absolutely clear.  I have scoured the Internet looking for similar stories, and found mostly concerns about defective grids, cracked manifolds and other concerns.  Fast forward to the Pentair User Manual for our system and in the troubleshooting section in the back of the manual, here’s what it says:
Issue: "A brief "cloud" of dirt may appear when the filter starts."
Response: "This is a characteristic of diatomite filters.”
I then called Pentair and spoke with a technical support representative and he confirmed that a small, brief “cloud” of dirt (this is actually DE and a bit of dirt) is NORMAL. I have never heard of this before, but there it is.  Now if your filter is emitting DE/dirt constantly back into your pool, that’s problem.  But this brief cloud at startup, I guess it’s something we have to live with.  I’d be interested to hear if anyone wants to contradict Pentair.  But they built the equipment and they say this is the way it is.  Kind of annoying behavior, but there you go.  
Here’s the Pentair manual: http://www.pentairpool.com/pdfs/QuadDEFilterIG.pdf