Help me dial in my SWG -- How much UV does an auto cover block?

[Jimrahbe]

Trey,

Not normal.. What brand CYA are you using?

There is another thread here, where the OP said he seemed to be having similar issues with his CYA levels.

Thanks,

Jim R.

 

[treyrich]

It was the Clorox brand I bought from Lowe’s. Is there a better brand? I actually originally suspected my CYA additions to be crashing my FC, but when I asked about it in my other thread it didn’t seem like it was possible without ammonia, so I dropped that line of thinking.

https://www.lowes.com/pd/Clorox-Pool-Spa-Clorox-Pool-Spa-Chlorine-Stabilizer/1001873978

 

[an1vrsy]

I have lurked on this thread. I have a similar setup, i.e. 26k gallons, autocover and IC60. However, I don’t use swg percentage changes based upon if the autocover is open or closed. I have my IC60 percentage set to produce 5 ppm, I run 24/7. It’s hot in Las Vegas and sunny. CYA 80. Although, it did rain/sprinkle this morning for an hour or so.

I am part of the #runhot team. Depending on the day and how long the cover has been open, I fluctuate between 8 to 10 ppm free chlorine.

 

[Newdude]

Could this contribute to the losses that we’re seeing since I’ve been maintaining things SUPER high for 50 CYA.

You would lose more FC during the day, but would have seen the overnight gain if CYA was the only issue. I go back to my original thought process.

1) algae. (Passed multiple OCLTs)
2) low CYA (didn't produce FC overnight)
3) defective cell.
*which was inspected and also verified to be running as it should

 

[Newdude]

Or.

Your cell is producing just a little (about .4 overnight). We usually see cells either work or not, and with the 2 polarities of production our options are 0/50/100% and we almost never see a 17%(etc) when its a hardware issue.

Maybe something changed or the system got an update and regardless of labels or what it reports, it's only producing in spa mode. For the pool volume, you'd see some FC but barely any.

(Y'alls will have to forgive me if I'm off base here. Automation to me is something theoretical that I've only read about and never seen............ like algae is to Jim, or rain is to Marty).

 

[Rancho Cost-a-Lotta]

I would recommend another OCLT due to inconsistencies in your previous tests.

On Tuesday night, your OCLT showed NO loss.

On Thursday night, your OCLT showed a loss of 1.0 ppm. This is concerning because it either means your testing methods are inconsistent or your FC loss in increasing.

In between, on Weds, you completed your overnight chlorine production test which should have resulted in a gain of 4.1 ppm. You only saw a gain of 1.0 ppm. Assuming your overnight loss is 1.0, your SWG showed a gain of 2 ppm.

A 24 hour FC loss test showed 3.0 ppm. Your showing some test with CCs at 0.5.

IS the water crystal clear?

It would be a easy to point to the SWG as the culprit, but it's the most difficult to diagnose and it seems to be functioning properly.

Below are some testing tips I put together based my observations since 2018. Some may not apply, but take the info for what it's worth:

• Usea sample bottle with a dropper style tip. Leslie's has nice ones they'll give you for free.
• Always rinse sample vials with pool water before and after use. With small sample size, even a bit of fresh tap water can skew results
• When using droppers, keep the bottle vertical. Squeeze only enough to allow the drops to just fall off the tip
• Go slow between drops (about 1 second between) and watch closely for color changes. On most tests, color hues are less important than determining the "endpoint."
• The endpoint for most "count the drops" type tests is when there is no more color change. Keep adding drops until there is no color change. Don't count the last drop that results in no color change
• For the first few tests, wipe the tip of the R-0009 TA bottle between each drop with a damp rag to eliminate static charge
• Use 10 mL sample size for FC/CC test (R-0870/R-0871/R-0003 reagents)
• Use 25 mL sample for TA test
• Use 10 mL sample for CH test
• For some tests, swirling is critical to achieve accurate results (there's a tool for that). Keep swirling the vial throughout the test.
• Get that tool when your budget permits. You'll be glad you did.
• Try to develop a routine and stick with it. Do the tests the same way each time.

I know your leaving town, so no hurry. I'm confident you'll get it sorted out.

Best of luck!

 

[treyrich]

Ok. I'm back in the saddle here. Here's some updates and answers.

Updates: Before I left on Thursday evening I dosed pool to ~20ppm with bleach (probably not exactly 20ppm but that's what I was aiming for). On both Friday and Saturday the pool had a medium-swimmer load, with no swimmer load Sunday. Sunday evening I tested and found FC at 17ppm, then again at mid-day today at 18ppm. The entire time that I was gone I had the IC-60 set at 60% which should (in theory) produce 6.5 ppm per day in my pool.

Today I ran another CYA test to determine if it had dropped even further, only to find that it was back up at 70. I have no explanation for this as I conducted 2 independent tests last week both indicating 50 (even comparing against the "50 control solution" I have, but I'll be the first to admit that my level of confidence in my CYA testing ability is pretty small so maybe this is all down to tester error?

Current test results from today:
==========================================
El Berro
------------------------------------------
Build Type: Plaster
Volume: 22000 gallons
------------------------------------------
Latest Test Result Summary:
FC: 18.0 (an hour ago)
CC: 0.0 (an hour ago)
pH: 8.0 (an hour ago)
TA: 90 (an hour ago)
CH: 275 (an hour ago)
CYA: 70 (an hour ago)
Phosphates: 250 (an hour ago)
SALT: 3000 (4 days ago)
TEMPERATURE: 85° (an hour ago)
CSI: 0.20 (an hour ago)
==========================================
I'll also point out that I did run a phosphates test and got a result of 250ppb, I don't know if that's good or bad, but I guess now we know?

Answers:

I would recommend another OCLT due to inconsistencies in your previous tests.

Will run another one tonight. I always do my tests the exact same, so I doubt there are "inconsistencies" with the way that the tests are preformed, however, what I'm never sure of is how well I should be rinsing the tools (vial, magnetic stirrer thing, fill bottle, etc). I've tried everything from dipping them all in the pool, to scrubbing them all with an alcohol wipe. Since this thread has started I've just been quickly rinsing them all in pool water before the test, so all the tests have been consistent, but maybe I'm not doing enough to keep the tools contaminate free?

IS the water crystal clear?

Yes, it has been crystal clear this entire time, looks like glass.

@Newdude I am totally tracking your comments, and don't disagree with what you're saying. It seems 100% clear to me that the SWG is definitely producing SOME chlorine, however the amount definitely seems to be off. I like your process of elimination, and I also like what @Rancho Cost-a-Lotta was suggesting as well that maybe I'm the problem. So perhaps we consider this table to help us eliminate issues:

Event	Rules Out Algae	Rules Out SWG Issues	Rules Out Testing Inconsistencies
Aug 5-6 FC Falls Faster than SWG produces
Aug 7 Pass OCLT w/ 0 loss
Aug 8 Run Overnight Chlorine Production Test with a 1ppm gain
Aug 9-10 Ran 24-hour Chorine Loss Test with a 3ppm loss
Aug 10 Pass OCLT w/ 1ppm loss
Aug 10 Tested Water away from returns against water coming out of returns while cell running. Water out of returns was 2ppm higher fc than that from away

Based on this table, it seems that the most likely issue is my testing? Followed by a possible SWG issue? I have ran tests multiple times back to back and gotten the same results, but that doesn't mean the day-to-day I'm getting the same results.

haha, I guess in summation, I'm still questioning everything...

 

[Rancho Cost-a-Lotta]

From TFP Wiki/Phosphate Removers:

The threshold limit for phosphate removal is around 1000ppb (1ppm), there is no point in removing phosphates if your phosphate level is below a 1000ppb.[2]

Try the OCLT again. See what Pentair and your PB can do for you regarding SWG diagnosis.

Welcome back!

 

[treyrich]

OCLT again passed with a 0.5 loss. I guess the more times I do these the less likely tester error is?

Here’s a question. Let’s assume there is an issue with the cell, but that at ~80% the cell maintains my FC. In theory does that mean that the cell is actually only being used at like ~40%? Therefore I’d get the lifespan of one at 40%? I guess my question is, if I can make this cell work for a while as-is, should I just do that instead of look to go down the warranty road?

 

[Newdude]

if I can make this cell work for a while as-is, should I just do that instead of look to go down the warranty road?

No. You paid darn good money for it to work properly. The more time that passes, the more likely the PB/manufacturer will be able to find an excuse why it's not their issue.

If you have a money tree out back and don't care about wasting funds, get them to replace the unit and do me a solid and send me the funds you didn't need.

 

[treyrich]

Hahaha, yeah definitely no money tree, mostly I was thinking that maybe I could get the same use out of it as one that was working as expected. But I assume no?

Any other tests anyone can think of that I should do to better isolate the issue to the SWG before I open up discussions with the PB?

 

[Newdude]

Any other tests anyone can think of that I should do to better isolate the issue to the SWG before I open up discussions with the PB?

IMO, you've gone above and beyond the norm before calling in the PB.

I was a service person myself for 20+ years and I rarely diagnosed things when I had easy access to replacements. There was always enough evidence to prove *something* was wrong with it, and if I invested alot of time to prove what it was, more often than not I was replacing XYZ anyway.

Going after the obvious issue often solved it, and if the trouble persisted it removed that part from the equation making further diagnosis that much simpler. In this case you can point to all you've done to prove it likely isn't the chemistry or a software issue.

 

[FlappyLipps]

When you didnt run the swg for a day what did your pool use for FC for the 24 hours ?

 

[treyrich]

When you didnt run the swg for a day what did your pool use for FC for the 24 hours ?

3ppm

 

[treyrich]

Ok, so I now believe that (despite all my testing) @Jimrahbe was correct here and there has to be algae or something somewhere still. I honestly cannot figure it out, but the chlorine usage seems to be climbing, with yesterday it using well over 5ppm with no swimmers or sun exposure at all (cover on).

So, I am close to admitting defeat here haha, my wife thinks I’m insane and I’ve spent a ton on bleach in the last couple of months, and countless hours chasing this issue. I need help desperately. Should I start a new slam thread? Use my old one? Or use this thread?

 

[Jimrahbe]

Should I start a new slam thread? Use my old one? Or use this thread?

Trey,

I just keep it right here..

In theory, if you have algae, you should fail an OCLT.. Just want to confirm that when you ran the OCLT, your SWCG was off.. ???

With your cover on, I would assume your FC usage would be close to zero, unless you have algae.

Also, if your pool used 5 ppm of FC yesterday, why did your salt cell not replace it??? Edit.. I assume your cover was on and the cell was either off or running at a very low output..)

How long do you run the cell each day and at what output percent??

In most cases we recommend running a SLAM with the cell off.. In your case, I suggest that you run the SLAM with the cover closed and the Cell on full blast. I'd open the cover a couple of times a day to vent the CC's. Then after a few days, turn the cell off and see if you can maintain the FC with just liquid chlorine.

Keep in mind that I have never had to do a SLAM, so I don't usually post about them.

Let's see if we can get Matt to double check my response... Calling @JoyfulNoise

Thanks,

Jim R.

 

[treyrich]

SWG was running at 60% over the 24 hour period where I lost 5ppm. So in theory (if we assume SWG is working as designed) I lost close to 11ppm. I’m still not really trusting the SWG, but everything I’m experiencing is pointing to something consuming FC.

I did t do an OCLT, I will tonight, but just based on what I know about this pool at this point, it’s time for SLAM, but I can’t figure out how I could have passed so many OCLT and never dropped below the top of the FC range and still find myself in this situation. Only thing I can think of is that none of my previous slams have actually killed everything, but I don’t know what to do if that’s the case haha very depressing.

Glad to hear that you’ve never had a slam, you’ll be my role model, I think that after this slam I will have been slamming more days than not slamming since this pool has been finished.

 

[Jimrahbe]

Trey,

The main problem when doing a SLAM is "maintaining" the SLAM level... Often people will dump in a bunch of chlorine one day and then do the same the next day, not actually maintaining the SLAM level.. Another thing is that brushing the pool is a real pain in the rear and something a lot of SLAMers just don't do like they should.

If I ever have to do a SLAM, I plan on basing my SLAM on a higher CYA than I think I have, and for a day or two longer than I think I need. If I'm going to have to do it, I want to be the last one I ever have to do...

Anyway... good luck with your SLAM.

Thanks,

Jim R.

 

[treyrich]

I just finished searching once again for algae, I couldn’t find anything. I took a video, but it doesn’t seem to want to upload (are videos not supported?).

I removed all drain covers, speakers, speaker grills, umbrella holders (no umbrella has ever been in the pool), and I scrubbed and vacuumed every hole I could find. I also swam under and inspected the entire cover. I found no visible algae anywhere, not even a hit of cloudiness in any of those locations.

I guess I didn’t do an OCLT, so I’ll do one tonight, but it sure feels like I’m using a lot of chlorine and haven’t been able to get it consistent since I owned the pool. But maybe the pool just uses random amounts of chlorine and there’s not a way to dial in the SWG the way I want? It’s odd because I agree it sure seems like the pool should use next-to-no chlorine while covered not in use, which is making me feel like I’m missing something…

 

[FlappyLipps]

The only way I believe your pool is using 3 fc per 24 hrs then, The next day loosing 5 fc while the swg is running 60% for 24 hours.
The swg made 0 fc and the day your pool used 3 fc it was cloudy and the day it used 5 fc was straight sun.

The water temp falling 4 deg and then coming back up all with it a few days tells me clouds also.

You need to turn the swg off, leave the cover open and do a OCLT, Test after dark and before the sun rises.