Guidance needed, 3 years using TFP and I am at a loss (Solved)

[jsnpckns]

Hello!

I haven't posted much because I usually don't have issues. Something has developed over the past week, and I am at a loss as to what can be the cause.

Background: As of around 2 weeks ago, the oaks have started dropping catkins, and we have had very little to no rain. Weather has been in the 70's during the day and mid 50's to 60's at night. I have been cleaning the pool out multiple times/day to get the pollen/catkins out. I did have one morning, Monday I think, when I overslept, and the skimmer was jammed full of catkins. I cleaned the skimmer and the pot. I keep a skimmer sock in the skimmer basket and regularly run my surface skimmer bot and s200 dolphin. The water is clear to the bottom.

*edit* Filter got new cartridges at the end of spring last year, baseline 7 psi, pressure reads between 8 and 9 right now.*edit*
*edit* I did add some water to the pool on two occasions over the past week, about 1/2 inch each time since its been dry and windy and I don't like my first shallow entrance step to not be under water. I have not tested this water lately.*edit*

Chemistry, going back to Mar. 16th: (I know there is no 75 CYA or odd number pH values, I just record them that way if I have trouble reading the dot or the color comparator)

March 16th
FC 6.6
CC 0
pH 7.5

March 21st
FC 6.4
CC 0
pH 7.5
TA 50
CH 210
CYA 75
Salt 3200
Temp 63

So everything up to this point is pretty much how the pool has been running all winter. I went a while on checks because our temps dropped again. Then on Apr 3rd:

FC 4.0
CC 0.0
pH 7.6
TA 50
CH 230
CYA 75
Temp 73
Salt 3800 (added 40 lbs to make the SWCG happy, and was expecting a lot of rain we never got)

Ok, not a big deal. I chalked it up to being lazy, but wasn't surprised, So I upped the SWCG to 20% from 17%, expecting that the warmer days were eating more Chlorine, and I put in 16 oz of bleach to catch it up to closer to where I should be. I expected to be above 5, closer to 6, FC, but my next check on the 7th:

FC 3.0
CC 0.0
pH 7.4
Temp 70

So I added more bleach, 32 oz, and bumped the SWCG to 30% at around 1 pm. I checked it again at 7 pm and got 4.8 FC/0.0 CC. It should have been higher, just from the bleach. I couldn't figure it out except maybe the bleach was no good anymore or I had something going on biologically. So I was prepared mentally to have to start a SLAM, turned the SWCG to 0%, and got up early to check the levels. This reported at 3.8 FC/0.0 CC. Even though it was only 1 ppm difference, I went to the hardware store and got 3 gallons of 10% pool Chlorine.

I added the chlorine in parts to each of the 3 jets at around 8:30 a.m. I spent the next 2 hours brushing and scrubbing everything, clean skimmer, scooping any catkin/leaf debris out that I could with the net. I checked the the FC just after noon, and it was 13 ppm. With 8400-ish gallons, I thought it would be in the 20's still after only 4 hours, especially since my OCLT was only 1 ppm over 12 hours.

I am at a loss as to what is wrong. I don't if there is something wrong with my test chems, if the bleach was weaker than advertised, or if could be algae even though the pool is crystal clear with no signs of anything that I can see. I repeated the drop test about 15 min later, from a different part of the pool, using the 10 ml sample size and got 14, so the result is repeatable. I have done these 100's of times now, but maybe I am making a mistake? The chems are new since the end of summer, both the powder and the drops. I keep my glassware clean and rinsed and each test has its own vial.

Do I just keep adding more bleach to continue the SLAM? What could be eating ~15 ppm of FC? I am fairly confident that my CYA is above 70 at least, but maybe I need to double check that? Advice/Direction/Guidance/Adult Beverage appreciated.

 

[HermanTX]

especially since my OCLT was only 1 ppm over 12 hours.

Was your SWCG on or off during this test? Also was it near dark when you took the initial reading and then not quire light when you took the 2nd reading? The goal is to isolate the UV loss of FC. The measure should only be what is in the pool that could consume FC.

Also, it is best to test CYA and pH before any SLAM to know your starting points.

 

[jsnpckns]

The SWCG has been at zero since around 6 pm yesterday. The first OCLT was around 7:15 pm and the second was this morning just after 6:30 am.

I recorded pH for both OCLT tests, so I knew that number and CYA was only 5 days ago with no rain or pump off, so I figured it hadn't changed.

I just can't account for a 1 ppm OCLT result and then being short 15 ppm FC of expected FC 4 hours after adding 2 gallons of 10% bleach. If it is bad chems or something else that SLAM can't fix, I don't want to keep adding bleach if it won't fix it or make matters worse.

 

[Dirk]

Possibilities (however remote), including the possibility that more than one of these is true:

- Weak bleach. Buying bleach from anywhere in the Spring could mean buying last year's supply. Buy only bleach from a reliable source that is stamped with a date code. The code can be hard to decipher, so look to TFP for the way to decipher them. @ajw22, where is the key for the codes? The stocking methods at big-box stores are horrible for chlorine.

- Bad testing chemicals. Buying them last summer does not mean they were new last summer. Do they have an expiration date? Even if they do, you don't know they were handled and stored properly before you bought them. Buy another set. If it turns out the first set was fine, you'll still be able to use it all. If not, you've got at least a partial answer.

- Your SWG could be going out. Do you know how to test it for hours used? Check the manual for that. Do you see the "Cell" light coming on as expected? Do you see small bubbles coming out of the returns when the cell light is on?

- Could an animal be fowling the water regularly? (Kids are animals, too.)

- You have organics in the water or filter (or both) that are using up the chlorine. If you eliminate all of the above, SLAM away! And do a deep clean of anywhere algae could be hiding: skimmer, filter, light niches, ladders, vacuum hoses, brush and pole, etc. Sleuth time!

 

[Newdude]

where is the key for the codes?

In the Wiki at the bottom of any page

Chlorine Date Code Decoder - Further Reading

www.troublefreepool.com

Step one in this situation is to add your bleach, mix it for 15 mins and see where you landed immediately.

Whatever it tests hours from now is moot if you never got near target.

 

[jsnpckns]

Possibilities (however remote), including the possibility that more than one of these is true:

Weak bleach - It is CDS liquid chlorinator from Ace. Code is 23236 13:10 CP2 then under that is 230823-1 55852-IL-001. So I assume that is 236th day of 2023 at 1:10 pm. That's a bummer, then the bleach I started with in the earlier additions was definitely weak as well I guess. I was trying to save a few dollars because the pool store Liquid Chlorinator is like 25 a gallon for 12.5%. This feels like the actual culprit for my math not lining up with test results.

Chems - The drops expire on 5/24 and 6/25 respectively (I finished one bottle on the 12 oclock test, and started a new one on the 4 and 7 oclock), the powder expires 6/24. I will look at getting a TFP kit and compare it to the Taylor and see.

SWG - This was my first reaction, that there was something wrong with the cell. The cell light comes on according to the proper portion of 5 min increments. No small bubbles coming from returns. I will check the unit for hours after this post and update.

Animal - This is not entirely outside the realm of possibility. We have many racoons and other critters. I have often wondered if any of them have been having overnight parties in the pool. I haven't seen anything on the blink or nest cams, but possible I guess. No humans have been swimming yet this year.

Organics - Other than the catkins, just small debris from trees and leaves. The pump pot is clean, and I empty the skimmer basket multiple times a day now, but I have not cleaned the filter this year. I was waiting for the wife to get back home to help with that. Maybe something there as well.

Step one in this situation is to add your bleach, mix it for 15 mins and see where you landed immediately.

Whatever it tests hours from now is moot if you never got near target.

I see. I did not think it was important to get it right away since the process requires me to keep adding chlorine to hit the mark. Now I see, I never knew for sure I was hitting the mark to being with, which was a poor assumption on my part. I was just alarmed that the number was so low, but now I see that the bleach might be the culprit for the huge disparity in my expectations? I fully understand what you are saying though, and I will make that best practice from now on. If I had done that, it would have been readily apparent I guess that the bleach was weak or not.

I took 2 more samples since Noon. At 4pm, 10 ml sample gave me 12.5 ppm FC, at 7 pm another 10 ml sample gave me 12.5 OR 12, it was hard to see the pink and I was being assaulted by about 100 bloodthirsty gnats. I feel like, given this, the culprit is likely the bleach. Both my original container which was a few months old and the new ones which are definitely old. This would explain the previous deviations in results from expected values, both in the normal test and the SLAM. I am not discounting that other factors or a combination could be at play, so I am going to go with 12 for the start point of a new OCLT and check again in the morning. If the result is outside the criteria for a SLAM then I will source a better liquid chlorine and start over.

Thank you both for the knowledge and centering my thinking. TFP is a treasure of the internet. I will update the post tomorrow (I guess I should do one more normal 25 ml sample for accuracy to compare to the morning?)

 

[Dirk]

Work first through the SLAM (if necessary) and getting your readings and dosing working correctly with liquid chlorine. Once you have that down, and can pass the OCLT, then you can fire up the SWG and troubleshoot that if it needs it.

FYI:

Seeing bubbles from the returns (or just one return), while the SWG's Cell light is on, means the SWG is producing hydrogen gas (that's what the bubble are), which means the SWG is producing chlorine.

Not seeing bubbles from the returns can mean two things:
1. The bubbles are being produced, but just not making it all the way to the pool. They're getting "reabsorbed" into the water before they can exit the return(s). (Pardon my un-scientific explanation.) In that case, your SWG would be OK.
OR...
2. The SWG is not producing chlorine.

All that is easy enough to test AFTER you are sure your pool is free of algae and that it can maintain FC as expected. So, again, get a handle on that first before figuring out if the SWG is working or not.

 

[Dirk]

I assume that is 236th day of 2023 at 1:10 pm.

That's 7 months, 2 weeks old today. That's pretty bad even if the chlorine was handled and stored correctly (like in a sunless, somewhat coolish environment). Which it probably wasn't. If it's been abused all this time, you can use it for emergency water! (Kidding, but it's probably close to done, in not completely done.)

I've learned here that lower percentage chlorine (like 6 and 7.5%) is less prone to degradation due to age. 10% gets worse, 12.5% even worse. Though I don't know the exact expiration expectation across all those various strengths.

Anyway, sounds like you've got some good clues to work through.

 

[jsnpckns]

That's 7 months, 2 weeks old today. That's pretty bad even if the chlorine was handled and stored correctly (like in a sunless, somewhat coolish environment). Which it probably wasn't. If it's been abused all this time, you can use it for emergency water! (Kidding, but it's probably close to done, in not completely done.)

I've learned here that lower percentage chlorine (like 6 and 7.5%) is less prone to degradation due to age. 10% gets worse, 12.5% even worse. Though I don't know the exact expiration expectation across all those various strengths.

Anyway, sounds like you've got some good clues to work through.

Yes, you gave me some good info to orient myself. Learn something new every day, mainly like don't make assumptions lol. And I should know this as a former chemist. I just got lazy and trusting... or laissez faire since I usually only use bleach in the winter when the SWCG isn't making chlorine, and that is infrequent. I should have just adjusted the swcg more to make up the FC to 6 instead of shortcutting with the bleach and setting the swcg where I thought it would maintain that level.

I went out and pressed the more button on the SWCG until it cycled its scrolling lights, none of the percent lights came on, after cycling the other lights, the Cell and flow light flashed green at the same time then it returned to green flow light/"Good" salt light with no cell light since its still at 0% until I figure this out. I assume that means I am still under 2000 hours run, which by napkin math I did last night with "bad swcg" in mind, about fits. I run it the same hours every day, and looked at the seasonal averages, assigned 91 days by 12 hours by their seasonal percent and multiplied it times 3 gave me just over 1500 hours, which is about right considering the unit will be 3 years old in May.

I will tackle the water fundamentals first like you said though. Thanks again!

 

[Dirk]

like don't make assumptions lol.

Well, expecting someone that sells something to provide a product of good quality is a reasonable expectation. We should be able to assume that. Unfortunately, that is no longer the world in which we live...



I buy my chlorine from a local Leslie's. It's right across the parking lot from a big-box, where it is cheaper. But I've seen the big-box just stack new chlorine on top of old, which means someone down the road is going to get really old chlorine! And it's out in the garden shop, where it gets hot during a hot day.

Just a theory, but I expect Leslie's has a lot less room to store chlorine, and so goes through it faster, which might mean it's more likely to be fresher. Plus I like having the Leslie's there, for emergencies, so that's how I support them. Like you, I only use LC in the winter, so the total difference in price by buying it at Leslie's is minimal.

 

[jsnpckns]

I got distracted last night, and fell asleep without doing a 25 ml sample test. So this morning I did a 10 ml sample to compare apples to apples, and it was FC 11.5, and CC 0.0. The water is clear with a little debris that is obviously catkins and leaves and tree detritus.

I am going to test again this evening to get one more OCLT start number with a 25 ml sample. If Wed. morning it passes, I am going to switch back on the SWCG once the FC gets to around 7 and see if I can dial that in to hold. If not, that will give me time to source some more reliable liquid chlorine and start over on the SLAM. I won't be lazy this time and follow NewDude's advice and get the brush and help the pump mix it up and get a more immediate number. After that I think I'll be fine.

After looking at the bleach degradation charts, just by months alone even stored between 75 and 80, puts it in the 6%-ish range. Plugging 6% into PoolMath, it lines up more closely with what I saw from my 2 gallon addition. I guess I'll set aside the remaining gallon and the rest of the original gallon for cleaning and get my bleach as needed instead of trying to keep it on hand. Lesson learned!

Thanks again!

 

[PoolStored]

10ml sample is fine...can't remember when I ever used a 25ml sample to test. No need to burn up reagents.

 

[Newdude]

I'd fail myself at 1 with a borderline pass, because if I was wrong, it'd be a super easy SLAM. .8 wouldn't make me feel any better about it if that's what the 25ml sample said. Lol.

 

[jsnpckns]

So I took two more samples just after 7 pm. 10 ml sample came back at 8 ppm, and 25 ml sample came back at 7.4 ppm FC. Being within a drop of each other makes me confident to continue using the chems. The morning FC was 11.5, so that's a loss of 3.5 which seems a bit high even for daytime and a cloudy one at that. I'm going to test first thing in the morning around 6:30 and see. But I feel like I'm going to have to slam. Hope the pool store near me has good Chlorine.

 

[Bperry]

So I took two more samples just after 7 pm. 10 ml sample came back at 8 ppm, and 25 ml sample came back at 7.4 ppm FC. Being within a drop of each other makes me confident to continue using the chems. The morning FC was 11.5, so that's a loss of 3.5 which seems a bit high even for daytime and a cloudy one at that. I'm going to test first thing in the morning around 6:30 and see. But I feel like I'm going to have to slam. Hope the pool store near me has good Chlorine.

I’m confused. If last nights sample was 8ppm and this morning sample is 11.5, then you gained chlorine overnight not lost.

Edit: I see, you havent done the OCLT yet.

 

[jsnpckns]

Yes, just observing the day's consumption. Sorry for the confusing wording. It is all moot now. Mother Nature is pressing the reset button as a river of rain comes in from the Gulf. *sigh*

 

[Bperry]

Yes, just observing the day's consumption. Sorry for the confusing wording. It is all moot now. Mother Nature is pressing the reset button as a river of rain comes in from the Gulf. *sigh*

Drain some of the pool in advance and its like a free bit of help getting rid of algae.

 

[jsnpckns]

I think I found the culprit. The filters were a bog. They were new at the beginning of last January. I bought Optimum Pool Technologies Pool Filter 4 Pack because they were a little cheaper. The start pressure was 7 psi, and before I took them off to clean today, they were at 9 psi. As dirty as they were, I would have expected a higher delta. When I got them, the end caps were a little rigid, and the 4 way top cap from the housing was not as snug as on the original filters. Maybe they are leaking by at the ends and that is throwing off the pressure?

Anyway, after the storm, I tracked FC down to around 10. Turned the swcg back on when it got to 8 FC but was still seeing a 0.5 to 1.0 unexpected difference the next day. I feel confident the swcg is making chlorine though as I ran it overnight at 30%. Night FC was 8, morning FC was 10. It should have been closer to 11.

With the wife home to help, I cracked the filter open, looked in and said "found that 1 ppm!". At least, I am pretty confident that is it. Attached pic to show the difference. Going to do another OCLT tonight to be sure. There was mostly muddy black silt/dirt, but also a lot of catkin pods and shredded old oak leaf material, black as night.

New start pressure is 8, but I am just going to start cleaning them every six months until I need new filters. The filters are in good enough shape, no fraying at the bands or on the pleats. They came about 90% clean.

Thanks again for all the help and advice. It is nice to have someplace to go keep my type-A anxiety in check with common sense.

 

[jsnpckns]

Oh jeez now I look at the pic, the ends are not even flat. Ffs.

 

[Dirk]

25% of 7 = 1.75
7 + 1.75 = 8.75
9 > 8.75

From the TFP guidelines linked below:

When the pressure rises by 25% over your starting pressure it’s time to clean out the debris that has been collected by the filter so you have room to catch any new debris that enters the pool. Failure to keep the pressure in the normal range can greatly reduce your water flow, resulting in cloudy water, poor circulation and excessive wear on the pool equipment.

You were [just slightly] past due for a cleaning, which means you're not doing it enough (which, of course, you already figured out). So the numbers and the symptoms track.

Maintenance and Cleaning of Pool Filters

Maintaining your swimming pool filter system is important. Learn how to clean and maintain your pool filter at low cost & enjoy a Trouble Free Pool.

www.troublefreepool.com

Without much evidence to the contrary, I still think it best to buy replacement parts from the original manufacturer. Pentair charges an arm and a leg for just about all of their products, but their quality is usually top notch.