pH rises .1-.2 daily

[howardpassman]

Hi, I'm hoping to maybe get some help figuring out why lately my pH increases almost daily. I'm attaching my measurements in pdf format. This is almost everything I track. I do use a mineral pack because I've found it seems to take some of the work off of the chlorine. I definitely have less demand for chlorine when a mineral pack is used. I was going to try to not use one this year, but I found the demand for chlorine to be much higher, so I installed one a few weeks in to the season.

My pool is 18,000 gallon gunite. I use Chlorine bleach (8.75%) and I lower the pH using muriatic acid (31.5%). I have sheers, but haven't used them lately. I also have a spa seat, but it is also off.

The list of the types of chemicals I used are on the spreadsheet. I copied the spreadsheet and eliminated columns and rows that I don't feel are important.

I hope I've given everything that may be needed. I know I'm probably forgetting something.

Thanks for any help in advance.

Howard

 

[DaninFLA]

Well you FC is way too low for your CYA levels. if you are losing too much FC from the sun, then you should bump up your CYA to maybe 50. mineral packs are going to be bad for you in the long run, which it seems you already know.

your TA is relatively high, but a pH increase of 0.1 or 0.2 per day isn't out of the question. keep lowering it down to 7.2 with muriatic acid and the constant rise/lowering will lower you TA and your pH increases will slow down.

not sure why you would be adding pH increaser when you are concerned about high pH?

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I would suggest you read up on pool school. you are spending a lot of money you don't need to on chemicals/mineral packs.

your minimum FC for your current CYA level is 3ppm, and the target is 5ppm. you barely have any readings above the minimum. you need to be adding for chlorine. your perceived chlorine issues are because they are too low and you probably have algae growing in the water.

 

[ping]

What type of test kit are you using? The pH jumped over 1 point in one day with nothing going on that should raise it that much according to your chart. With those types of numbers it looks like some type of digital pH tester, I wondering if the calibration of the pH test is off.

 

[howardpassman]

I knew I forgot something. I use the Taylor K-2006 kit and additionally I use the Hannah HI-98128. I always use both for pH measurements because I don't trust the digital tester. My reagents are new this season and I calibrate the Hannah meter bi-weekly. It's stored in the storage fluid, cleaned with their cleaning fluid and calibrated with their buffer solutions. I really try to cover all my bases on the testing.

The pool get minimal use by just myself and my wife. It's really perplexing to me.

BTW, my chlorine measurements are done in the a.m., 24 hours after adding chlorine. I don't use an erosion feeder so most of the time there is about 3ppm of chlorine in the pool during the times it's being used. Since my CC never seems to get out of hand I don't worry about having 3ppm of FC. Also, I did raise my CYA because I thought that may be the reason I was using more chlorine, but it seems to be from not using the mineral pack. After installing it chlorine use seems to have dropped.

Also, my pump runs 24/7

Thanks,

Howard

What type of test kit are you using? The pH jumped over 1 point in one day with nothing going on that should raise it that much according to your chart. With those types of numbers it looks like some type of digital pH tester, I wondering if the calibration of the pH test is off.

 

[howardpassman]

Thanks Dan,

Actually, i used pH increaser only back when it was low. I have no issue with the mineral pack in that it does relieve the load on the chlorine a little and my pool is black inside, so staining isn't much of a problem for me. My TA isn't high when you add in the cya. The AlkC is within range except after I keep adding acid. Then I have to add some backing soda to get it back. I didn't put my AlkC reading in the pdf. I think I'm o.k. in those areas.

Thanks again,

Howard

Well you FC is way too low for your CYA levels. if you are losing too much FC from the sun, then you should bump up your CYA to maybe 50. mineral packs are going to be bad for you in the long run, which it seems you already know.

your TA is relatively high, but a pH increase of 0.1 or 0.2 per day isn't out of the question. keep lowering it down to 7.2 with muriatic acid and the constant rise/lowering will lower you TA and your pH increases will slow down.

not sure why you would be adding pH increaser when you are concerned about high pH?

- - - Updated - - -

I would suggest you read up on pool school. you are spending a lot of money you don't need to on chemicals/mineral packs.

your minimum FC for your current CYA level is 3ppm, and the target is 5ppm. you barely have any readings above the minimum. you need to be adding for chlorine. your perceived chlorine issues are because they are too low and you probably have algae growing in the water.

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Is there any chance the age of the pool has any bearing on this issue? The pool is now 14 years old.

Howard

 

[chem geek]

If you were starting to see Calcium Nodules as either slag piles on the bottom or drips on the sides, then the pH can rise significantly as calcium hydroxide enters the water, some of which becomes calcium carbonate that forms the nodules. That happened in my pool and my pH rise was substantially faster for a couple of years before it settled down again.

 

[howardpassman]

Thanks Chem Geek

No piles on the bottom. There are a few very thin traces on a few tiles. It's really hard to tell on the side of my pool because it was originally black and has faded, but I don't see or feel anything that resembles drops. Just what looks like a little calcium on a few tiles that I already mentioned.

In your case did you just waited it out? Do you know the cause? I thought maybe there wasn't enough calcium, so I raised it from around 200 to 250. That didn't seem to help and I may have been barking up the wrong tree, but I'm still well within range.

If you were starting to see Calcium Nodules as either slag piles on the bottom or drips on the sides, then the pH can rise significantly as calcium hydroxide enters the water, some of which becomes calcium carbonate that forms the nodules. That happened in my pool and my pH rise was substantially faster for a couple of years before it settled down again.

 

[howardpassman]

Thank you for the link Chem Geek. I read it and i do have 3 places on the side where this occurs. I'll see if I can remove it and seal the plaster in those spots.

 

[DaninFLA]

well if the pool is working for you the way you are doing it, then keep on doing what your doing. but your method doesn't follow the TFP process, so don't have much to add. if it were me, I would convert 100% to the TFP method and save me lots of money.

 

[howardpassman]

Thanks Dan. I'm not sure what a lot of money is, but last year I spent $992 for everything inclusive of chems, testing kit, new o-rings and seals throughout, one pump rebuild and replacement pH meter. No problems with algae or clarity. Other than the mineral pack, I do use the Pool Calculator and the recommended TFP chemicals. You piqued my curiosity, so I checked the amount of bleach I used before and after the installation of the mineral pack this year. Before the average was 76oz per day and afterward it was 41oz., so it does seem to have a positive effect on the chlorine demand. For some reason last year it was less and after then entire season it was 10.67oz per day. I guess I'll see at the end of the season this year what the total average ends up being. I figure as long as I don't have algae and my CC is never out of line, I'm golden. 14 years down the road and I'm still very happy with the pool.

Have a great day,

Howard

well if the pool is working for you the way you are doing it, then keep on doing what your doing. but your method doesn't follow the TFP process, so don't have much to add. if it were me, I would convert 100% to the TFP method and save me lots of money.

 

[DaninFLA]

how much are the mineral packs though?

you can figure out costs pretty easy, at least ballpark. assume that during 4 months of hottest weather, your pool is losing 3ppm of FC per day. for a pool of your size, that works out to 80 ounces of 8.25% bleach. say, for 120 days, that 75 gallons of bleach. assuming $3 a gallon (seems to be what people pay, ballpark), that's $225 for bleach. plus probably another $50 in muriatic acid...so under $300 for the swim season. that should be about it by going TFP method.

- - - Updated - - -

how much are the mineral packs though?

you can figure out costs pretty easy, at least ballpark. assume that during 4 months of hottest weather, your pool is losing 3ppm of FC per day. for a pool of your size, that works out to 80 ounces of 8.25% bleach. say, for 120 days, that 75 gallons of bleach. assuming $3 a gallon (seems to be what people pay, ballpark), that's $225 for bleach. plus probably another $50 in muriatic acid...so under $300 for the swim season. that should be about it by going TFP method.

 

[chem geek]

In your case did you just waited it out? Do you know the cause? I thought maybe there wasn't enough calcium, so I raised it from around 200 to 250. That didn't seem to help and I may have been barking up the wrong tree, but I'm still well within range.

I just waited it out. The cause is a bad (rushed?) plaster job where voids were created. I know this because of some delaminations where it's very, very obvious that large voids were created in some places so I figure they were sloppy in other places as well. It didn't start to show up until the 7th year, perhaps after some settling/shifting (maybe even Earthquakes -- who knows) but it was a pretty rapid pH rise using at least twice as much acid as usual and since I have an autocover there shouldn't normally be much pH rise. Eventually it settled down after year 9 though we still see a small number of new nodules every now and then. The pool is now 12 years old and when I get this replastered I'll make darn sure they do a good job and that they use a bicarbonate startup.

 

[howardpassman]

Sounds like a plan. Back when the pool was built they tried a new finish called sider, which was a cementuous mix, with no lime in it. However, the contractor had never used it and assumed it needed lime in the mix. When we opened the pool for the second season, the finish had fallen off. We were thrilled. Anyway, the pool builder had the same contractor come back and this time plaster it. I guess we can ow see how that went.

After your last response I looked at the link and I do have three spots that have what you were referring to. I'll try to fix them soon.

Thanks again and have a great day.

I just waited it out. The cause is a bad (rushed?) plaster job where voids were created. I know this because of some delaminations where it's very, very obvious that large voids were created in some places so I figure they were sloppy in other places as well. It didn't start to show up until the 7th year, perhaps after some settling/shifting (maybe even Earthquakes -- who knows) but it was a pretty rapid pH rise using at least twice as much acid as usual and since I have an autocover there shouldn't normally be much pH rise. Eventually it settled down after year 9 though we still see a small number of new nodules every now and then. The pool is now 12 years old and when I get this replastered I'll make darn sure they do a good job and that they use a bicarbonate startup.

- - - Updated - - -

Sounds like a plan. Back when the pool was built they tried a new finish called sider, which was a cementuous mix, with no lime in it. However, the contractor had never used it and assumed it needed lime in the mix. When we opened the pool for the second season, the finish had fallen off. We were thrilled. Anyway, the pool builder had the same contractor come back and this time plaster it. I guess we can ow see how that went.

After your last response I looked at the link and I do have three spots that have what you were referring to. I'll try to fix them soon.

Thanks again and have a great day.

I just waited it out. The cause is a bad (rushed?) plaster job where voids were created. I know this because of some delaminations where it's very, very obvious that large voids were created in some places so I figure they were sloppy in other places as well. It didn't start to show up until the 7th year, perhaps after some settling/shifting (maybe even Earthquakes -- who knows) but it was a pretty rapid pH rise using at least twice as much acid as usual and since I have an autocover there shouldn't normally be much pH rise. Eventually it settled down after year 9 though we still see a small number of new nodules every now and then. The pool is now 12 years old and when I get this replastered I'll make darn sure they do a good job and that they use a bicarbonate startup.

 

[howardpassman]

Hi Dan. Yes, I have figured it out. I'm retired and have little else to do Luckily for me my wife keeps track of every cent we spend and I had her run a report for last year out of quick books. I decided to go back to the mineral pack this year because using last years numbers for bleach compared with the beginning of this year, the pack ($89) saved me a few bucks. Although it wasn't that much, it did save me lugging as much bleach by almost half. I do spend $9 for three 121oz bottles of bleach at COSTCO, so that and the $89 for the mineral pack is what I base my annual costs on. I know you have my best interests at heart, so I thank you. If the mineral pack is my only bad habit, I'll be happy.

PS My wife just reminded me that number includes $250 for water.

how much are the mineral packs though?

you can figure out costs pretty easy, at least ballpark. assume that during 4 months of hottest weather, your pool is losing 3ppm of FC per day. for a pool of your size, that works out to 80 ounces of 8.25% bleach. say, for 120 days, that 75 gallons of bleach. assuming $3 a gallon (seems to be what people pay, ballpark), that's $225 for bleach. plus probably another $50 in muriatic acid...so under $300 for the swim season. that should be about it by going TFP method.

- - - Updated - - -

how much are the mineral packs though?

you can figure out costs pretty easy, at least ballpark. assume that during 4 months of hottest weather, your pool is losing 3ppm of FC per day. for a pool of your size, that works out to 80 ounces of 8.25% bleach. say, for 120 days, that 75 gallons of bleach. assuming $3 a gallon (seems to be what people pay, ballpark), that's $225 for bleach. plus probably another $50 in muriatic acid...so under $300 for the swim season. that should be about it by going TFP method.

 

[DaninFLA]

I hear you, like I said, if its working for you stick to it. didn't mean that in a rude way, not sure if it came off that way.

but for your original question on pH, I don't think its that fast a rise. my pool still goes up pretty quick. when I hit 7.8, I lower it to 7.2. about 4 days later its 7.8 and I repeat. that's 0.15 per day. I have a similar TA number as you now. I started higher but its coming down from the muriatic acid additions. im not too worried about it, as long as im in the range.

 

[howardpassman]

Thanks Dan. Between what you just said and what Chem Geek said it sounds like I'll be doing the same thing.