What Not To Do To Your DE Filter

[Katy-Texas]

OK so with the pool 1.5 years old and still problem of fines in pool I final found 2 hours to do my first ever annual tear down cleaning of our Pentair FNS 60+ DE filter.

Holy crud Batman ! OK so not a pretty picture. Most DE etc at top of unit, between fins at top is completely plugged and when look down the middle you see a core of DE that is still left after removing all the caked up fins.

This pool boy has been good at maintenance, backwashing several times until clean returns when pressure builds up and then adding ~6 lb of new DE via skimmers.

Where did I go wrong or is this what it's supposed to look like ?

Snaps attached:

[MaryLee]

I have the exact same filter. We usually open our pool on Memorial Day and close mid-October. The pool company does the closing which involves tearing down the filter and cleaning the grids. I don't believe I've ever seen the filter that dirty. Then again, we are only using the pool for 5 months and then closing....Sorry not much help

[Katy-Texas]

Thanks MaryLee

Lucky you have your own Poolboy ! Here I have to do it, plus we run our pool year round with no cover. So at least I know this is not normal .

[MaryLee]

So at least I know this is not normal .

Actually, it might perfectly well be normal for a pool that is open year round. Hopefully someone else can chime in

[waterbear]

There is actually a technical term for the caking of DE that your pictures show. It is called 'bridging".

I have said many times before in the forum that backwashing a DE filter is NOT a good idea and that they really should be torn down when they needs to be cleaned. Not a popular opinion in the forum, btw! Your pictures illustrate my point perfectly! The problem with backwashing is you never really know how much DE is washed out and so you never really know how much to put back in. If you put in too little you run the risk of clogging the grids with dirt and organics. If you put in too much you can cause bridging between the grids and the DE can cake into a cement like mess....sort of like in your pictures! The errors can compound with each backwash.

It really does't take THAT much time to break it down and clean it properly if it is done on a regular basis! Save backwashing for time that you are killing an algae bloom and are trying to get suff out of the pool and when you are done break it down, clean it, and recharge it with the proper amount of DE!

Just my 2 cents (for the umteenth time it seems! Maybe someone will take note of what I have been trying to say!)

[tenax]

holy crap..no insult intended, but methinks i'm very happy i have a sand filter

[Katy-Texas]

Thanks all. Yep, agree with Waterbear! I now resolve to tear down and clean every 3 months !

Another question, the cloth on the fins was rough, almost crunchy, felt a little like rough grit sand paper when sliding the fins down beside each other. Manual said that may get "Liming" on fins where get some scale buildup (initially filled pool with hard tap water, just this week gettig a water softener installed). So I think that is the problem. Manual said if "Liming" to bath fins in mild HCl soln. They are tall so I was thinking of doing this next tear down in a clean tall plastic garbage can.

Agree?

[imfignewton]

You can buy a solution to soak your elements in. It will be acidic and have something in it to break down oils on the elements. A large plastic garbage can from Sams Club works great for soaking DE elements.

[huskyrider]

Actually I didn't think it looked that bad, I've seen them much worse after several years of service without being broken down and cleaned. They simply backwashed over and over again. These folks explained that we used to go for months between backwashing and now it's gone to a matter of days and we always made sure to add our DE after backwashing, LOL!!!
I have to somewhat disagree with waterbear. IMO a DE filter should be broken down and cleaned after every third or fourth backwash.

See Ya,
Kelly

[waterbear]

Actually I didn't think it looked that bad, I've seen them much worse after several years of service without being broken down and cleaned. They simply backwashed over and over again. These folks explained that we used to go for months between backwashing and now it's gone to a matter of days and we always made sure to add our DE after backwashing, LOL!!!
I have to somewhat disagree with waterbear. IMO a DE filter should be broken down and cleaned after every third or fourth backwash.

See Ya,
Kelly

Huskyrider, let me ask you this....what happens when you run a DE filter without DE in it? the grids foul, right? Why is running unfiltered water
BACKWARDS through the grids not going to foul them just as easy?