Cleaning quad de 100 filter

[MattM]

So, on friday, I took the plunge and finally got around to cleaning out the quad de 100 for my 4 month old pool. For the last week, the water had looked dirtier than normal, very small stuff on the top of the water(pollen?), and I knew chlorine/cya/chems was in good shape....besides, getting rid of any plaster dust is always a good idea.

First time opening up the filter, some comments/questions:
a) pentair instructions say to tighten until each side of spring is just touching, I think I did that but am also worried I might have tightened too far
b) the drain thing on the bottom of the filter uses a builtin plastic nut to loosen/tighten and seems to easily deform, worried I'm going to have to replace the cap there if I am constantly opening/closing it.
c) the de cartridges seem easy enough to clean, hose worked fine and media seems sturdy enough not to get damaged easily
d) so, what am I supposed to do about all the de that falls off the filter when cleaning...a bunch fell in a grass area and seems to stick to the soil/clog drains...swept up as much as I could
e) I assume rough ballpark is fine enough for filling up de again, I started pump and then dropped roughly 12lbs of de into skimmer (~2x what was on bag for 48sq ft filter), I slowly dumped in...but didn't dilute before hand..was I supposed to?
f) I'm still somewhat curious what time frame I should get between cleaning of the quad de 100, for a 24K gallon pool...I was told that it would be roughly 6-12 months...not sure if that is realistic.
g) how long does de last, I know it is supposed to stay in the filter, but I assume some gets lost as part of normal process...including occasional opening of pressure relief valve when performing other pool maintenance....will de stay in filter fine for 1yr?
h) Unfortunately, the pressure gauge barely changes as the filter gets dirty.....maybe a half point of psi at most so far...filter psi after cleaning was barely distinguisable from dirty
i) it seems to take a good yank to get the main screw released when unclamping and the spring releases pretty strong slamming the metal belt against my hand (not looking forward to repeat).

But overall, if this isn't a too frequent a task, should be easily doable on my own. I just hope that I'm not having to clean it every 3-4 months.

 

[JasonLion]

a) You should be fine.
b) I have heard of them failing, but it isn't usually an issue.
d) If it is a problem you could put down a tarp.
e) It depends on how tight your ballpark is. 11 lbs would be more or less fine, 8 lbs would be too little.
f) As long as you don't get algae, 6 months to a year is totally realistic.
g) It should be fine for more than a year, and you should clean the filter at least once a year anyway.
h) That means you are cleaning the filter too frequently. Wait for either a year or the pressure to go up 6 psi, which ever comes first.
i) Try gentle tapping with a hammer.

 

[MattM]

Well, I must have done something wrong when cleaning the quad de 100 a few weeks ago. My son noticed some small white things entering pool via returns two weeks ago. I assumed it was cya since I had recently added it. Then last week, I found white stuff near the deep returns and hoped it was just a one time thing, today we noticed for at least a few minutes that DE seemed to be entering the pool in the middle of the afternoon with no obvious cause (pump had not just been turned on or any speed change).

So, I'm wondering if I'm going to have to open up the DE filter again and what I should look for. Pressure in the filter seems normal and outside of a few minutes/day, all seems to be running normal....

 

[carlscan26]

Could it be CA from the SWCG? Or is it not dissolving?

If it really is Dze you will need to,reopen the filter - make sure the assembly is fully seated. Also make sure the screen and spring on the top are correctly installed.

 

[MattM]

I have a guess at what the problem is:
- I'm only noticing stuff enter the pool when there is alot of waves from kids jumping up/down/etc (it is a rare occurance, and that is the only common thread I can see). The kids have been active in the pool lately, especially as water temp has been 86+ degrees the last few weeks.
- On at least one occasion, it appears that weir in skimmer briefly was pushed up all the way and we only have 1 skimmer so pool pump got some air in it, shortly after is first time I saw one of the events
- So it seems like something is flowing back from filter only when pump briefly gets lots of air accidently put into it by heavy water activity

Now, if you remember, a long time ago I had a thread about poor skimmer performance and one of the corrective acts was removing the waterway thingie underneath the skimmer basket...(the purpose of that thingie is to prevent exactly the type of event that is described above, from what I can tell). So, I've put it back in and will continue to monitor.

Normally the water suction is 80% skimmer (3" pipe), 20% main drain(2" pipe) so if the pump is priming or very briefly running at high rpm, we might see the waterway shut down the skimmer briefly to prevent air from going in - which should cause main drain to take over for a brief duration.

Can't say if what is going back into pool is DE or undisolved cya, it has a white appearance...someone said it looked like salt.

 

[carlscan26]

That sounds more like CYA - DE looks like a fine powder/dust

 

[carlscan26]

How long ago did you put in the CYA and how long ago did this problem start?

 

[MattM]

A few things of note (which make it more likely that we're looking at calcium scaling):
- Pool has had slightly negative csi (-0.1 to - 0.2) since startup
- Increasing temp of pool + bumping borates/cya + accidental increase of TA + drop of ph from 7.6 to 7.5 has brought CSI to ~+0.05
- SWG is only a few months old, if any calcium scaling occured prior, now might be when we would see it?
- Seems to occur even with waterway thing in skimmer (perhaps just a few times/day?, I only see it when kids are in pool though).
- I have an IC60 swg and the local fill water varies in CH, but frequently can have high values.
- CH in pool has otherwise been steady (went to 275 in first month after startup, has stabilized at or under 300).

So, to say for sure, should I try to vacuum up the flakes and put them in diluted muriatic acid and see if they disolve quickly/completely?

 

[carlscan26]

Did your mean positive .5 or 0.05? .5 is getting up there but five-hundredths is nothing.

If its flakes then most likely it is the SWCG precipitating calcium - there are posts about this - IIRC running the swcg at high percentages makes this more likely or noticeable. But as long as these dissolve away I wouldn't worry about it.

How about a full set of test readings too just to confirm?

 

[MattM]

My last test readings:
PH 7.5
TA 150 (apparently covered pool doesn't get much aeration)
CH 300
FC 6
CC 0
CYA 33 (could be +/- 10 easily)
TEMP 87
BORATES 37 (hard to get an accurate reading with test strips)
SALT 3350 +- 400

Will likely try bumping ph down to 7.4 regularly for a few weeks to bring down TA.

 

[carlscan26]

That puts your CSI at 0.06 which is great. I think you're seeing calcium flakes from the swcg. Do you have any other actuators? Are they working?

You're going to have to go lower with the pH and open the cover to aerate,etc. to get that TA down. I don't know that moving pH .1 at a time will have much effect. Will you be disabling your pH control to do this?