Can't get the pool clear even with SLAM

[flasherz]

Hi all,

This year has been particularly troubling for our pool, almost as bad as the 2013 year when we had a crazy pink slime invasion that had me 10 minutes from buying a few hundred ton of backfill dirt.

33,000 gallons
FC: been holding at 40-50
CC: 0
CYA: 60
TA: 110
CH: 300
pH: tends to run about 7.2-7.4 normally, FC > 10 so I can't measure right now

Bottom line: I just can't seem to get the pool to go and stay clear this year. It went cloudy earlier this year, in mid-June. It was getting hard to control, and I knew our CYA level was too high from trichlor use (when liquid chlorine was very difficult to find), so we replaced over 1/2 the water and got it down to 60. It was a beautiful, blue color but would never clear up. We are on a well with some iron, but a little bit of sequestrant holds it.

Next step, I replaced our 10 year old sand with new zeolite filter material. While I was cleaning out the filter, I checked the laterals and they look good. It didn't improve anything materially.

I'm in day 7 of a SLAM and it's not getting any clearer. CC is 0, OCLT has passed several nights in a row (0 loss last night), but it's still very, very cloudy. We're brushing all the surfaces and vacuuming daily. Pressure is normal, there's good flow through the filter.

Here's the pool brush in the water. What am I missing here?

 

[Texas Splash]

A few comments/questions about your post:
1 - Which test kit are you using? It's not in your signature.
2- An FC of 40-50? If that's true, you risk damaging your liner. There is no need to have an FC that high. An FC of 24 is plenty based on your CYA.
3 - While Zeolite is used by some, I would've stayed with sand. It's the gold standard for pool filtration.

If your testing at such a high FC level is accurate and you passed several OCLTs are you noted, then it must be a filtration issue.

 

[cledee]

Since you have metals,
I've also experienced cloudy water from sequestrant use (more specifically ProTeam Metal Magic made my pool Cloudy as it was reacting with metals and Calcium). It took over a week to clear, even though I had no algae, all my test revealed everything was in range, including overnight chlorine loss and CC being less than 0.5.
It could be that you have cloudy water from both things and it's taking longer to clear.

 

[mgtfp]

It's very unusual to have absolutely no chlorine loss over night with such high FC. Chlorine is always oxidizing something, even if it's just the CYA in the water, and the resulting losses are proportional to the FC-level. That's why the pass criteria for an OCLT are relatively generous with 1ppm so people aren't chasing ghosts when trying to pass it.

At 50ppm FC you should have some noticeable chlorine loss over night. The 1ppm OCLT criterion is really only applicable when at or under SLAM-FC, at twice the SLAM-level I'd expect actually more than 1ppm loss over night even in a perfectly algae-free pool, unless the water is quite cold.

I'm wondering if there's something wrong with your test reagents that's playing tricks with you.

 

[flasherz]

A few comments/questions about your post:
1 - Which test kit are you using? It's not in your signature.
2- An FC of 40-50? If that's true, you risk damaging your liner. There is no need to have an FC that high. An FC of 24 is plenty based on your CYA.
3 - While Zeolite is used by some, I would've stayed with sand. It's the gold standard for pool filtration.

If your testing at such a high FC level is accurate and you passed several OCLTs are you noted, then it must be a filtration issue.

Apologies:

1. TF-100 test kit, fresh reagants.
2. I recognize this, I raised it in the past couple of days from the 25-30 range I had kept it at. The liner will be replaced next year anyway, so I'm not too concerned with that at this point - I just want clear water.
3. I've read good things about Zeolite and not really many negative things, and I got it at the same price as filter sand. Either way, it appears to be filtering as it is pulling out the algae (as evident through the last backwash water). That said, the cloudiness was persistent well before I replaced the sand with Zeolite.

Returns are strong, the draws through the skimmers are good, not finding any sand or Zeolite in the pool. What else can I do to validate / verify filtration? I suppose I could just buy a couple of bags of sand and swap out some of the Zeolite just to create a layer of the "gold standard"...

 

[flasherz]

Since you have metals,
I've also experienced cloudy water from sequestrant use (more specifically ProTeam Metal Magic made my pool Cloudy as it was reacting with metals and Calcium). It took over a week to clear, even though I had no algae, all my test revealed everything was in range, including overnight chlorine loss and CC being less than 0.5.
It could be that you have cloudy water from both things and it's taking longer to clear.

I applied Metal Magic at refill time and haven't added since. I'm willing to stick with it, but 3 days of no improvement is beginning to concern me.

 

[flasherz]

It's very unusual to have absolutely no chlorine loss over night with such high FC. Chlorine is always oxidizing something, even if it's just the CYA in the water, and the resulting losses are proportional to the FC-level. That's why the pass criteria for an OCLT are relatively generous with 1ppm so people aren't chasing ghosts when trying to pass it.

At 50ppm FC you should have some noticeable chlorine loss over night. The 1ppm OCLT criterion is really only applicable when at or under SLAM-FC, at twice the SLAM-level I'd expect actually more than 1ppm loss over night even in a perfectly algae-free pool, unless the water is quite cold.

I'm wondering if there's something wrong with your test reagents that's playing tricks with you.

TF-100, brand new reagants from this year, and it appears to test correctly. With much lower chlorine levels it has always matched the basic test kit indication.

Last night I measured 50.0 at 8:30 pm and this morning, 50.0 at 6:30 am. *shrug* There is a slight risk of error due to the fill of the cylinder, but I pay particular attention to that due to other jobs where I have to do the same measuring. I really don't know what to say (although I have more reagant on order because - as you can imagine - I'm going through at lot right now!)