Chlorine Level dropped to zero overnight

Hi folks, looking for some opinions here. The pool stats:

Located in Southern NH, two year old 39k gallon Gunite pool.
Opened again last week of April, it's been a cold spring, water temps past month hovering around low to mid 70's in June though it did reach 80F with some water heater help a week ago.
Chlorine and UV/Ozone system (yes I know opinions on that)
We have a chlorine disk feeder system, I've been keeping it loaded every day to the top. It uses roughly 2 disks per day in order to maintain 2 to 3 ppm free chlorine level.
My test kit is a Taylor K-1005.
I've been using the pool service of our installer, every two weeks, since install. I watch everything thing they do, read this forum, and test daily because I'm an anal nut.....trying to learn enough to eliminate the service cost.
We've hardly used the pool since opening in April, so very little contamination. It's located in an open area, gets all day sun, no trees, nothing besides pollen and the occasional frog in there, pool is spotless and the water perfectly clear.

The following situation happened this week, and it happened once last month two weeks after opening. The pool is perfectly clear, chlorine at 2 to 3ppm, pH at 7.5 maintained with muriatic acid periodically, total alkalinity at 90, calcium hardness at 400. Everything looks perfect, I'm able to maintain this with little variation over a month. The pool service guy comes this past Tuesday, I watch him test (more expensive Taylor kit), he has roughly the exact same results as mine. He doesn't add any chemicals, checks also clarity says it's perfect. Pool looks great that evening, no rain overnight so nothing changes, I go out to test the pool mid morning Wednesday and the chlorine is zero, I mean absolute zero ppm. I look at the disc feeder, it's down two discs like normal which means it's feeding chlorine into the water.

First thing I do is put the disc feeder on maximum flow, and I add a single disc in each of the two filter baskets in the pool. I retest mid day yesterday, it's still zero. At days end I pour in two gallons of super shock. According to the label that's may half of a normal shock treatment for my size pool, but I only had two gallons. I test this morning (Friday), now I get a chlorine reading over 5 ppm....so I'm back with some chlorine in water.

Also to mention, my first thought was my test liquids from Taylor need to be replaced. They all have 2024 usage dates on them, but I bought replacements last month from Taylor just in case....plus I test a lot so figured I'd use them up. I parallel path tested with the new test liquids yesterday, same results....the new liquids had 2025 usage dates on them.....so I think I eliminated the test kit as the issue.

What I need help with.....I'm able to maintain very consistent chlorine ppm for numerous weeks, with extremely consistent chlorine disc usage, and then in the bat of an eye, the level goes to zero.....not even gradually, it just disappears. This has happened twice in a month.

Any idea what could cause this, for sure I'm missing something.

Confessions of a former salt hater

I thought this post of mostly what not to do, would be helpful for those like me! Pig headed!
Pool installed, 1998. My first SWG was from a startup company out of, Utah. I made the mistake of getting a unit that was much too small! I fought a green pool for a year off and on! It died and the owner, David upgraded me to his latest, much larger unit. It died in three months and he replaced it under warranty. That one lasted a year. I later discovered the failures were my fault, a wiring error! I had a dual speed motor at the time, and I picked the wrong tap. When the motor was in low speed, it always made a growling sound with the SWG powered on! The SWG was wired in series with the motor’s winding! Oops.
Once again, David replaced the unit, now with his latest, water cooled unit! It also had a copper ionizer as part of it. My motor died and I went single speed at the same time and I also installed solar panels. Good for a few years, and then the control unit started leaking. This time, David didn’t want to cover it under warranty, but gave in! This unit lasted 4 years or so.
I never went back!
The anchors to my pool cage rotted out, I blamed the salt! Have since had it proven to me, not a salt problem!
Through all of this, I also used chlorine pucks. My clever trick of maintaining pH! I plead ignorance!
The family insisted on a 95 deg pool, and with the SWG being water cooled,(and sitting in the Florida sun) it was overheating!
Everyone complained about burning eyes, salt blamed! But CYA was extremely high because of the tablets. And never measured!
Oh, and with copper, shall we talk about green hair?
Ashamed to admit, through all of this, I never measured salt levels! I would just throw in a bag or two when the pool started getting ready to do an algae bloom!
  • Like
Reactions: markayash

Pentair 400 Mastertemp (6 years old): AFS error

Hello,

Thanks in advance for the help and comments.

I have a Pentair 400 Mastertemp and I am currently getting a AFS error. I have checked the other threads on here regarding this issue and haven't pinpointed the issue that I am having.

- I have checked the airflow sensor and that seems to be operating properly.
- Blower seems to be moving enough air

I was able to get the heater to fire up by pulling the 240V red wire (12 position receptacle) and restarting the heater. The system would turn on, the blower would kick on, and after a few seconds I would hear the gas valve turn on and the ignitor would fire. Now, that trick doesn't work.

Any ideas?

Thanks,
Doug

Equipment Pad Sloped Too Much?

I bought a new heater and took the opportunity to pour a new concrete pad prior to installing. (Old pad was pieced together plastic bases)

Pad is approximately 6'x3' and I accidentally sloped it too much in the 3 foot direction (total drop of 1" in the 3ft). It's pretty flat in the long dimension.

I'm worried if the equipment (specifically the heater) will be ok installed with that much slope? I took a picture to give a visual sense of the install. I took the pic when the phone indicated it was level so the pic is pretty accurate to what it looks like in person.

Do you think it'll be ok? Should I try to shim the heater to level it out before making final connections?

Id appreciate any thoughts on this.

Thanks
Ron

Attachments

  • PXL_20230616_135202390.jpg
    PXL_20230616_135202390.jpg
    449.8 KB · Views: 28

Backwashing suddenly loses all water then slowly builds up again, cycle repeats

Good morning... I noticed one of my returns not having flow yesterday and again this morning. I went to backwash my sand filter and it would run fine for a minute then suddenly no water and no flow. I would wait and the flow would build up again, backwash appropriately for a minute, then again no water and no flow. I let this run for at least 10 minutes to see if it would "clear" but it kept happening. I went to rinse, no flow. Went to filter again and the flow built up, worked, then again it would go to zero, returns no flow, then again start flowing slowly and build up only for the cycle to repeat.

Do I need to deep clean the filter? Should I troubleshoot anything else? Maybe recirc or bypass? My first time ever having a pool.

New to pools

Hello, I am so glad to have found this place. I would much rather take care of my pool than someone else and have been studying everything you all have on the site for the last day and a half. I have been dealing with a pool for almost 5 years but my kids were small so the pool stayed small and it was easy with the chemicals and keeping it clean. This year I went a bit bigger and got a 4,200 gal pool instead of 3something. Well it's been open maybe 3 weeks, my kids and neighbors kids have enjoyed it but the darn thing got cloudy and I tried to do what I normally did but after reading this site I realize that was wrong. So the pool is clear until whatever is on the bottom (nothing visible) of the pool gets disturbed and it becomes a milky cloudy look. I went and got it tested at Leslie's and like everyone here has said I got a multitude of chemicals suggested (clarifier too) with no results. I have been scrubbing the pool with the brush, running the pump 24/7 (it's been 4 days), checking ph and chlorine levels at home and at Leslie's, since my vacuum uses a bag and garden hose I added a sock to help catch small particles, I do a minimum of cleaning cartridge filter once a day but when I am home I was doing it twice. I even put a new filter in thinking maybe the other was clogged up cause of all the chemicals. Well on the fresh filter last night it looked like yellow granular all over it. I almost started thinking maybe it was sand from one of those sinking toys, could it be pollen clinging to whatever the clarifier does?. I also always used powder chlorine and etc which I read along with the clarifier each on their own can make cloudiness worse. I have always hated the test strips but other than my simple chlorine/pH test kit I didn't know what to do. With this sites advice I purchased the TF-pro with smart stir. I am going to overnight chlorine loss test tonight but I have a gut feeling it is algae but we will see.

Question.. my ladder for the pool is easily removable and when we are done swimming I like to remove it and store it in the shed. I initially did this cause my kids were small and it was for safety reasons as well as because I read how the ladder can rust. My question is...am I making my job harder by doing this? Is it exposing it to too many other factors that will mess up my chemicals in the pool or is this ok to do as long as I do not visibly put it in a bunch of mess? (I store it in a shed)

If I start using liquid chlorine is it still recommended that I have a chlorine tablet holder in the pool at all times? The store said it's a must but now I am questioning everything they taught me.

Thanks for your help and any suggestions.

Cloudy after SLAM

Hi pool experts! I used cal-hypo to slam because that's what I had on hand and I definitely made a big mistake - my beautiful pool is now cloudy after running the sand filter for 12 hours. Did I destroy my pool? I decided to SLAM after my pool wouldn't hold chlorine after 48 hours of "super coordinate" and then adding 4+ cups of liquid chlorine a couple days later. I then added 2lb of cal-hypo shock and it dropped to 0 after 18 hours. I am adding chlorine at night. I'm just south of Boston and weather has been a mix of cold (45°) and warm (80°) but mostly 60° or so.

Taylor test kit k-2006

Before SLAM:
FC 0
TA 120
CYA 60
pH 7.4
CH 250
SALT 3200

After SLAM FC is 25ppm

SWG
Vinyl liner
15500 gal
Taylor test kit k-2006

New Member & Pool Owner

Hello,

I am a new member and pool owner! I'm very new to this so please be kind. lol

I have a vinyl 15k gallon kidney bean shaped pool.
Pool pump: JVS 165S
Pool Filter: Pentair FNS Plus 48

The winterization done on the pool was terrible and it took a few weeks to get the water clear.

My pool water keeps turning green after shocking. I'm using "Leslie's Power Powder Plus Calcium Hypochlorite Pool Shock" I hadn't added anything in a week and there's been a lot of rain so I added 1lb last night and woke up to a green pool.

This is the 3rd time my pool turns green after adding the shock. I get it back to clear by adding about 2lbs of "Leslie's - Soda Ash pH Up". It normally clears up after an hour or two.

I also notice that my fiber glass steps get yellowish when the water turns green. I've read that it could indicate high levels of metal, how do I test for that?

I used the TF-Pro to conduct my tests this morning and have the following results:

Chlorine Only
8 drops of R-0871
8 x 0.5 = 4ppm (FC)

Combined Chloramines
3 drops of R-0871
3 x 0.5 = 1.5ppm (CC)

Calcium Hardness
5 drops of R-0012
5 x 25 = 125ppm (CH)

Total Alkalinity Test
9 drops of R-0009
9 x 10 = TA 90

CYA Test
Black dot is partially visible so it's >0; <30

PH
7.5

Cl Br
5 10

I used to have Leslie's test my water and buy all the things they "recommended" but my levels never get ideal so I decided to start testing myself. I'm hoping to get some assistance with what I can use/add to my pool to get it to ideal levels.

I've spent a ton of money already trying to get the water right and I'm still having some issues. Please help!

Thank you!

Underwater light mounting screw

Our pool is roughly two years old, and when I opened it in the spring, the underwater light fell out of the (plastic) wet niche. The brass / bronze mounting screw had corroded away. The instructions that came with the light state that the hardware must be replaced with the same type and size. I have no problem putting a brass screw back in the spot, but I'm wondering if the corrosion is a sign of something bad happening with the pool bonding system or some other issue. Or is two years about the lifespan of this screw in a SWG pool?

Hayward AQL-COLOR-MODHV Will Not Connect to Prologic

Hey Guys,

Two years ago I installed my inground pool with a Colorlogic 4.0 LED light. I run a AuquaPlus system with version 4.47 software installed. I added a AQL-COLOR-MODHV module to connect to my lights. After installing the the AQL-COLOR-MODHV the prologic should have automatically detected it and the ColorLogic Config menu should have been added to my configuration menu to allow to to find and program the lights, the menu does come up. I have double checked all wiring, and even purchase a second module to test that also would not connect either. I have called hayward but they never get back to you after multiple cases and there is no hayward specialist in my area that I could pay to come over. If anyone has an ideas I am willing to try anything to get this light working. Thanks in advance,

Shain

Beautech Made pool Cloudy

Hello all.

Added a bottle of Beautech to a pool in Indiana on 6/9/23. Water started to turn cloudy on Tuesday 6/13/23 and by Thursday 6/15 it was all the way cloudy, cant see bottom step.

fiberglass pool
cartridge filter

I cleaned the filter on Tuesday, normal amount of debris came out. I clean the filter every week

using a taylor test kit chemistry on Tuesday was
Chlorine 10
Ph 8 (5drops to bring it down to 7.4)
Alkalinity120
Salt 2590
(normal is 3060 so i added a 1/2 bag of salt)

Salt cell has a clear housing that you can see into and on the return side of it, it has always been retuning cloudy water. This was never an issue because the filter was always able to filter it out. Any ideas how to fix the cloudy pool?

Persistent Algae on walls of catch tank of wet edge / infinity edge pool

Hi,

The catch tank of our wet edge / infinity edge pool just has a plain plain troweled or brushed concrete finish and we are constantly having green algae appear on the walls below the water level.
The main pool is coated in pebblecrete and does not seem to have any problems.
The chemical balance / chlorine levels have been well maintained for the last couple of years thanks to TFP and a good test kit. There is no combined chlorine and free chlorine levels are good at 5 or 6 - sometimes higher - but if the catch tank is not scrubbed weekly algae will inevitably appear, even in the depths of winter (which isn't that cold in Sydney, Australia).
We did have some serious algae problems a few years ago due to a bunch of problems that have all been sorted, I think, and we had a final long SLAM to sort it out.

I wonder if algae has gotten deep into the "raw" concrete and is now impossible to shift?
Do we need to drain the catch tank and attack it some other way. Acid wash? Algecide? Paint the catch tank?
Any thoughts or solutions gratefully accepted.

50,000 liter pool.
oversized SWG
Pebblecrete finish on pool
Plain / brushed concrete in catch tank


Pool1.jpg catchtank.jpg


Thanks.

Chris

Salt Level in a Non-Salt Pool

I purchased a Circupool salt system for my parent's pool. Before installing I wanted to test the pool's salt baseline so I ordered the TAYLOR K-1766 SALT TEST KIT. To my surprise the pool's apparent baseline is 2800ppm for sodium chloride. Is that normal for a non-salt water pool? It took 14 drops of R-0718 to turn the solution to brick red. 14x200= 2800. I'm surprised the baseline is this "high". What could cause this? Their pool is about 7500 gallons. It's a diamond bright inground pool located in Florida. They mostly use liquid chlorine with about one 3" tri-chlor tablet in a floater per week. They do shock it every other week with Clorox Shock XtraBLUE.

Could the shock and tri-chlor tablets caused this "high" salt baseline?

Newbie just switched to SWG

Hi, after finally getting very comfortable with testing and keep out chlorine pool balance, we had our SWG Hayward Aquarite installed today.
I'm reading that I will be retesting my CYA ( which has been 60) and possibly adjusting that higher and then measuring my free chlorine as before. Here are my questions ...
1. Is there a chart or part of the app that will give me a starting percentage for the SWG. I loved using the one where I would put what my free chlorine was and what I wanted it to be and the app would do the math and tell me how much I should add.

2. How will I know when I need to add salt and then how much will I know to add.

3. I see a wide array of pump running times. We have been doing 24 hrs.. will that still be ok with the SWG?

Bugs!!

We have had a problem with what I think may be backswimmer nymphs all over our pool. Chemistry is good, chlorine is good , no algae, pool is clear . But they fly and jump into our pool by the 100’s and just crawl on us. They don’t go under water . I think they fly in and then don’t know how to get out . There are more and more everyday. We have a street light that shines into our backyard that our neighbor pays for and we can’t do anything about . Idk if that’s what our problem is or not. Help! We can’t even enjoy our pool . Here is a picture of one on our brick on the side of the pool. This picture B5A59492-89B9-4713-9A32-736CDCFB6894.jpeg

Hayward multi

Hey I have a Hayward sand filter that let green by on vacuum so we ordered a new valve head from Amazon because I couldn’t get the old spider out. The new spring bonnet and handle assy came with a little baggy with two orings and a Teflon washer with a split in it, anyone know what these are for? Not letting dirt by through the jets but pool won’t clear up! Gonna change sand and order a TF test kit asap. Thanks

Cya to chlorine ratio

I have been reading about cya/chlorine relationships. What I am having a hard time figuring out is how the 7.5x your cya is what you want in FC. From what I have read it only takes 50-100 ppb of HOCI (hyprochlorous acid) to sanitize. How I understand it chlorine turns into HOCI when combined with cya. So I guess the question is how do we determine how much hoci we have free vs how much is locked with the cya. I hope I am asking these questions properly.

RX clear, Doheny and waterway .. any good?

I’m in need of a new 425 sq ft cartridge filter for an inground pool and looking for cheaper but still durable options for my moms house. She doesn’t plan on keeping the house too much longer so we need something that will get us through the next couple of summers at least. RX clear, Doheny and waterway are all abt $500 cheaper then Pentair and Hayward but I’m not too familiar with those brands. Anyone use RX clear, Doheny or waterway 425 sq ft cartridge filters for in ground pool? If so how do you like them and how do they perform? And are either of the brands durable to last at least 2-5 years?

Poop. Lots of it.

We had a huge wind storm and it blew my garbage can full of dog s%#t into my pool and a ton of dust/dirt. Like I'm talking like a couple weeks worth of dog poop. I've tried to get as much out as possible, but it's starting to disintegrate. I'm at a loss. I dumped acid to bring my pH down to low 7's and added a bunch of chlorine. CDC says don't vacuum it up, but I have so much dust/dirt in the bottom of my pool as well. I suppose I can brush all the dirt and poop into piles and try and scoop it out? Most of it is in the deep end too, which makes it difficult to get out with the leaf scraper/net.

Any advice? I've scraped out a couple gallons of watered down poop, but there is more disintegrating and mixed with the dirt. Should I just sell the house?

What will happen if I use the vacuum all night at the highest pump speed? It's the vacuum connected to my filter system. Not a stand alone. I have a sand filter, 40K gallon pool. I was going to shock my pool to 25 ppm as my CYA is 70. Do I need to replace my sand in my filter after this?
Any help is much appreciated. Thanks.

Leveling the ground.

My husband and I recently put together and filled an 18 foot above ground Intex pool. Our ground seemed pretty level. We cleared it of rocks and debris. Put down the liner and built the pool. After filling it, it was really apparent how not level the ground was. So we drained it.

We live in a super rocky part of Texas, so digging out a bit of one side to help level isn’t really an option. So the next best thing seemed to be adding some soil to the opposite side and then we plan to cover the whole area in sand.

My husband is just feeling frustrated and like we should just give it up. I think we can do this. Any tips regarding leveling in this situation?

Thank you!

Filter