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GtownDan

Constant Ph Drift Up

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So my pH always drifts up. Using the Taylor test kit for Bromine, my initial readings were as follows:

TA 60 ppm

pH 8.0 (or more)

Bromine 9 ppm

CH 250 ppm

Added some baking soda to get TA closer to 75

Added some muriatic acid to try to get close to 7.5

Regardless of TA the pH always seems to be at 8 or more until I lower it.

350 gallon tub, 100 deg. F

Maybe I just need some borates. Any thoughts?

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I've used boric acid as a stabilizer for the last year... about 16 ounces for a refill.

After a refill, I work to get my TA down to about 50 with the pH in range. Usually takes about three to four days. Then I check the pH weekly with little changes shown. I use dry acid to reduce TA and pH. Then, I aerorate with the jets on high to raise Ph as needed.

I also use the dicloride/bleach sanitizer method.

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I am having issues with pH control in my tub, my fill water is crazy, pH- >8.0 and TA 220ppm. I had no issues getting the pH down to 7.4 and TA - 60ppm using muriatic acid and aeration. I do have a continuous recirc motor and Ozonator running.

My problem is my pH continuously climbs to 7.8 or higher. I know aeration causes pH climb, but I am not testing till the next morning 10-12hrs after use. I am running out of ideas. I have heard this area has really bad phosphates, but I am not sure what this would do to pH. I just finished a drain and refill 2 days ago, but I can't get the pH to stabilize at a normal level and looking for ideas. Do I need to get a phosphate remover and deal with that issue?

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You didn't mention what sanitizer you are using or how frequently you are using the spa and whether you are using aeration jets when in the spa. The ozonator will aerate the spa -- it mostly injects air into the spa with a little ozone added. You could lower the TA a little more to 50 ppm, add 50 ppm Borates, and target a pH of 7.7 -- don't try to get the pH to stay at 7.5. The phosphates should not be affecting the pH, assuming you are keeping it properly sanitized.

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PEOPLE I AM GOING TO MAKE THIS SIMPLE, HIGH TA WILL MAKE IT MORE LIKELY THAT YOUR pH WILL CLIMB!

THE HIGHER THE TA THE FASTER THE CLIMB!

THE LOWER YOU PUT THE pH THE FASTER IT WILL CLIMB!

THE MORE AERATION THE WATER GETS THE FASTER THE pH CLIMB. OZONATORS AND SALT SYSTEMS ARE SOURCES OF AERATION!

CONSIDER THESE FACTS THE LAW!

If your pH is constantly climbing quickly after you lower it then drop your TA. Period!

When you lower your pH don't drop it below about 7.6 and don't worry about dropping it again until it climbs ABOVE 7.8.

As chem geek said, adding 50 ppm borate and targeting a pH of about 7.7 will help but that any aeration will be working against you and if you have an ozonator or a salt system you have an additional aeration source besides whatever aeration the jets provide.

Aeration cannot really be controlled in most cases but the TA and pH can!

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pH & TA from a Newbie perspective

Let me start by saying I am by no means an expert in this area. What knowledge I do have is a result of reading many excellent posts by Waretbear, Chem Geek and others, while making just about every mistake a newbie could possibly make.

Once I got my Taylor 2106 kit I was bound and determined to get my water numbers perfect but really didn’t understand the pH – TA relationship so I found myself chasing my tail adding acid then baking soda over and over again. Looks like many others have found themselves in the same boat, so I’m posting this from a Newbie perspective.

1) Set your CH properly - I have mine @ 150

2) Set your TA to 80 (this is only a starting point) and stop believing that somehow it will magically stay there and don’t freak when it drops. I was testing almost daily and automatically added baking soda every time I got a reading below 80. Now I check it weekly and only add baking soda when it drops to 50. (add enough to return to 80)

3) Adjust pH to 7.6 and monitor pH every time you use the tub BUT only verify that it is between 7.5 and 8.0. Do not keep making adjustments if it’s within this range. I actually use a small OTO type test kit for this, not the Taylor, it gives a fast "Go / No Go" pH and BR reading. If the reading looks "No Go", I confirm with the Taylor and use the acid drop count to make adjustments.

Obviously aeration causes pH to rise and we all use the jets and air injectors in our hot tubs, so pH rise is an anticipated fact of life. Let it rise until it reaches 8.0 then adjust with acid. The addition of acid will lower the pH but the next time we turn on the jets, more bicarbonate will be outgassed thus lowering TA, but again don’t worry until it reaches 50. You’ll find that the pH rise will always be present but should slow down. Currently I find myself adding about ¾ oz. Muriatic acid weekly and about 3-4 ounces of baking soda every couple of weeks in a 350 gal tub.

I'm not sure what would happen if you don't add baking soda when the TA reaches 50 but like I said it takes a couple of weeks so it's no big deal.

BTW: This last water change I added 50ppm Borates (Borax + Muriatic Acid mixed in a bucket) The pH rise is still there but it gives you some peace of mind knowing that there is additional buffering so you don't panic when the TA hits 50 or lower.

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I'm not sure what would happen if you don't add baking soda when the TA reaches 50 but like I said it takes a couple of weeks so it's no big deal.

What would happen is that the rate of pH rise would be lower and the TA could still drop slowly if you keep adding acid. If, when it hit 40 you raised it to no more than 60, then you may find that your rate of pH rise and the amount and frequency of acid addition is less than you see currently. By going to 80 ppm, you are increasing the rate of carbon dioxide outgassing and therefore the rate of pH rise and amount of acid you need to add.

As waterbear noted, the basic rule is to just let the TA settle where it wants to, within reason. A low end of 50 ppm as a target is reasonable in situations where the pH tends to rise. As you point out, the use of 50 ppm Borates provides additional pH buffering so that the lower TA is not a problem.

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I'm not sure what would happen if you don't add baking soda when the TA reaches 50 but like I said it takes a couple of weeks so it's no big deal.
What would happen is that the rate of pH rise would be lower and the TA could still drop slowly if you keep adding acid. If, when it hit 40 you raised it to no more than 60, then you may find that your rate of pH rise and the amount and frequency of acid addition is less than you see currently. By going to 80 ppm, you are increasing the rate of carbon dioxide outgassing and therefore the rate of pH rise and amount of acid you need to add.

Thanks Chem Geek for the info.

It is becuase of posts from yourself, waterbear etc... that us newbies are actually getting a handle on keeping our spas safe and balanced.

I will alter my routine and set my top target to 60 and trigger point to 40.

Would it make sense to raise my CH to 200? I'm looking at the pool calculator and with a TA of 40 and pH 7.6 the CSI is -0.56 (if I keep the CH @ 150).

We use our tub at least 5-6 time a week for 40mins +, with all jets on, so I'm resolved to the fact that pH rise will be a fact of life.

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You don't need to worry about the CSI if you have no plaster or grout surfaces exposed to the water. If you have an acrylic spa, there should be no concern. Usually 150 ppm CH is enough to prevent foaming. If having the CSI lower, you lessen the chance of getting any scaling in the event the pH ends up getting very high (8.0+) anyway.

And yes, with your usage and amount of aeration, pH rise would be likely to occur. Technically, it would stop at an even lower TA and higher pH and some spas use large phosphate buffers to stabilize pH as a result, but that's a whole other approach (and requires a lower CH since calcium phosphate would precipitate).

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Ok here is where I'm at.

I let the TA drop below 50 and the pH is steady @ 7.6 but my TA is slowly dropping. I think I now understand the factors working against me and just need to maintain a simple routine to keep things in balance.

1) I have a 24hr circulation pump with an ozonator that is constantly aerating the water (pH +)

2) I use Waterbear's 3 step bromine system which I understand is net acidic (pH - )

I've revised my routine to check TA weekly and add enough baking soda to raise it to 50 when it hits 40. I check pH daily but only add acid if it's above 7.8. Nobody ever said that hot tubs are "Maintenance Free" so small adjustments are normal. Looks like the "trick" is find a TA that keeps adjustments to a minimum. I doubt there is such a thing as "Set it and Forget it" at least not for my tub. This week all I added was 44g of baking soda and havn't added acid for almost a week.

Thanks everyone

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Hello all.

Thanks for all the fantastic info on this forum. I've learned so much. I just bought my first spa, 500 gal Artesian Island and love it. Had it for 2 weeks and am researching chemistry and sanitation like a mad man to the point of obsession. The spa has an ozonater and the dealer set me up with an initial Spa Frog system. I've got 1 unused bromine cartridge and once it is done I'm dumping the Frog for bromine tabs in a floater (I've researche the 3 partbromine set up system). We have heavy use with teenage kids and friends and the low level of bromine was not keeping up with the bio load. With all the dichlor/bleach additions it makes no sense to spend the money on the Frog IMO. I initially was shocking with MPS and swithched to dichlor. After learning about the CYA I've swithched to bleach since the CYA levels should be more then sufficient now..

I have a good understanding of basic chem and the relationship between TA and pH as I also have a reef aquarium. I understand that borate helps buffer the pH by keeping the alk from dropping. I currently have the following parameters

pH 8

TA 90

CH 250

I've got a Taylor K2106 ordered and have been using my neighbors pool test kit . Here are my concerns.

1-Pool calculator states TA should be 50-80. Manufacturer states TA should be 80-140. Is low TA going to affect the spa in any hardware way physically, or only the pH buffering? I have not added boric acid yet until I get the TA proper.

2- Adding boric acid should increase the TA without affecting pH, thereby increasing the buffering capacity, correct? If so I can see why lowering to 50 is ok as the borate will increase TA back up near manufacture's recommended.

3- In order to maintain a sufficient Calcium level TA needs to be at a certain level to be balanced (at least it does in my aquarium) and stop the precipitation of calcium carbonate. Given my Ca level do I need to worry about Ca falling out of solution if I drop the TA further?

Thanks for any help and suggestions.

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If we want to the TA at less than 70-80 ppm, why does it state in the Bromine thread to raise it 100ppm? I am a little confused. I refilled my tub and raised the TA to 100 ppm as instructed, and have been fighting the PH being high untill recently by adding dry acid, not realizing I was lowering TA at same time. I finally have it somewhat coming down and I checked my TA and it is at 70 ppm. Why can't I start with TA at 50-60 ppm?

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The spa has an ozonater and the dealer set me up with an initial Spa Frog system.

The Spa Frog uses Bromine.

CYA is not an issue when using bromine as a primary sanitizer, only with chlorine. With bromine you do not need to test for or worry about CYA.

I have a good understanding of basic chem and the relationship between TA and pH as I also have a reef aquarium. I understand that borate helps buffer the pH by keeping the alk from dropping.

NOT quite, TA in a pool or spa is primarily carbonate alkalinity (in the form of bicarbonate at normal pool/spa pH range) The main cause of pH rise is from outgassing of CO2. High TA (bicarbonate) means faster outgassing since the actual buffer system is bicarbonate/carbonic acid and carbonic acid is essentially the same as CO2 in water for our purposes.

Borate will create a boric acid/borate buffer system. These two buffer systems work together to hold the pH at around 7.7 for a longer period of time than without the borate. Think of it this way, the bicarbonate buffer creates a tendency to have the pH climb because of outgassing of CO2 and the borate buffer, since it does not outgass, tends to counteract this.

I currently have the following parameters

pH 8

TA 90

CH 250

I've got a Taylor K2106 ordered and have been using my neighbors pool test kit . Here are my concerns.

1-Pool calculator states TA should be 50-80. Manufacturer states TA should be 80-140. Is low TA going to affect the spa in any hardware way physically?

In a word, no.

I have not added boric acid yet until I get the TA proper.

First step is to get TA in line then add borate so that is correct. You can do it the other way around but it is a bit slower.

2- Adding boric acid should increase the TA without affecting pH, thereby increasing the buffering capacity, correct? If so I can see why lowering to 50 is ok as the borate will increase TA back up near manufacture's recommended.

Nope, TA tests for TOTAL alkalinity, which would now be both bicarbonate and borate. Some of the boric acid WILL convert into borate which will measure as TA, Also, if you have been using dichor then some of the CYA will be in the form of cyanurate and that will also test as TA. However, the TA will still be primarily carbonate alkalinity so that is why it is important to lower the overall TA to around 50 ppm..

3- In order to maintain a sufficient Calcium level TA needs to be at a certain level to be balanced (at least it does in my aquarium) and stop the precipitation of calcium carbonate. Given my Ca level do I need to worry about Ca falling out of solution if I drop the TA further?

You are comparing apples and oranges (and I have kept reef tanks since the early 70's). First, the nominal pH in a reef tank is much higher than a pool or spa (8.2-8.3 vs 7.2-8.0) and the TA and calcium levels are also much higher (TA 120-150 ppm vs 50-100 ppm in a spa and CH 400-450 ppm vs 100-150 ppm in a spa) since calcium is constantly depleted by the organism such as corals, coralline algae, and mollusks that remove the calcium from the water and calcium carbonate gravel or sand (crushed coral) is used, along with calcium additives such as Kasserwater to keep the calcium levels saturated. The water chemistry in a pool or spa is much simpler! High pH is the main factor to indicate scaling conditions. High TA and CH are the usual factors that cause calcium carbonate to precipitate from the water when the pH is high. IF the TA is low there is less likelihood of precipitation of calcium carbonate.

Thanks for any help and suggestions.

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If we want to the TA at less than 70-80 ppm, why does it state in the Bromine thread to raise it 100ppm? I am a little confused. I refilled my tub and raised the TA to 100 ppm as instructed, and have been fighting the PH being high untill recently by adding dry acid, not realizing I was lowering TA at same time. I finally have it somewhat coming down and I checked my TA and it is at 70 ppm. Why can't I start with TA at 50-60 ppm?

You can but you have to realize that TA will NOT stay constant because bromine tabs are acidic and if you use MPS to oxidize, that is acidic also so your TA wil drop. Also aeration will cause pH to rise which means you will add acid which will lower TA along with pH. THIS IS WHY IS SAID TO ONLY CHECK TA MONTLY IN THE BROMINE FOR BEGINNERS THREAD! You only need to raise TA when it drops too low.

IF you are using dichlor/bleach or silver/MPS (Nature2) then lower initial TA is helpful since pH control is more critical. With bromine it is ok for the pH to rise up to 8.0. With chlorine you should keep it a bit lower.

Bromine is actually pretty easy to do and not a lot of work. Biggest problem is people making it harder than it really is and overthinking it. If you adjust the TA to 100 ppm and the just monitor pH you don't have to check TA for about month! If it is low (50 or below) then bring it up again! If you pH drops very low for no apparent reason then also check the TA, it is probably low. If so bring the pH up FIRST and then test and adjust TA.

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So rising up to 8 is OK for PH in a Bromine system? That is what I am using. Thanks for the explanation waterbear.

pH between 7.4 - 8.0 is fine for Bromine

If we want to the TA at less than 70-80 ppm, why does it state in the Bromine thread to raise it 100ppm? I am a little confused. I refilled my tub and raised the TA to 100 ppm as instructed, and have been fighting the PH being high untill recently by adding dry acid, not realizing I was lowering TA at same time. I finally have it somewhat coming down and I checked my TA and it is at 70 ppm. Why can't I start with TA at 50-60 ppm?

Waterbear's instructions call for an initial TA of 100ppm. This is actually a wise place to start. If you experience upward pH drift then just add enough acid to lower pH to 7.6. The spa will eventually find the "Sweet Spot" on it's own as TA slowly drops. You'll know the optimum TA for your spa when you test the pH and find it dropped. This will indicate the minimum TA for your spa as at that TA it can no longer counteract the acidity of the bromine system. For my spa that seems to be 40ppm but you could find that yours is 60, or even 70. There are too many variables in usage patterns, Bromine level, water chemistry..etc. Once you know your minimum then just maintain TA at "minimum" + 10 . For me that's 50ppm

My mistake, as indicated in earlier posts to this thread, was trying to maintain the TA at 100 and didn't let it drop.

For the past 3 weeks all I've added to my spa (other than routine doses of Chlorox) is 44g of Baking soda. pH has held steady @ 7.6 except when the TA reached 40ppm and the pH dropped to 7.4. That's when I added the Baking soda. I check my pH daily and it's back to rock solid 7.6

**Additional Note**

I'm quite comfortable running my spa at lower TA because of 2 things;

1) I have additional buffering of 50ppm Borates

2) I faithfuly check my pH daily

If you are unable, or unwilling to routinely monitor your pH then it would be safer to stick to higher TA.

Low pH brings a whole new set of serious issues. I'm sure that's why Waterbear recommended 100ppm for "Beginners"

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My PH settled in at 7.6 with the TA at 65 ppm. That must be the sweet spot for my tub. So dont woory abou the TA until it drops below 50 ppm and then rais only to about 70 ppm I am guessing? Can I add Borax detergent to help, or is that not a good idea? My tub is right at 400 gallons.

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You don't want to add borax DETERGENT! You want plain borax (sodium tetreaborate)., You will have to add acid to counteract the pH rise and you will need some LaMotte borate test strips (easier to read than the AquaChek ones) to test the borate level. You want the borate level to be 50 ppm.

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My PH settled in at 7.6 with the TA at 65 ppm. That must be the sweet spot for my tub.

Not sure how you measured 65ppm (My Taylor K-2106 can only measure multiples of 10 or 25ppm

So dont woory abou the TA until it drops below 50 ppm and then rais only to about 70 ppm I am guessing?

Please don't guess!!

I clearly stated to monitor your pH and when the pH begins to drop then that is the "minimum" TA for YOUR spa.

Maintain your TA at 10ppm above the point where pH drop is detected.

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Waterbear, I meant Borax, not detergent, but thanks for clarifying.

Spanky, I do have the K2106. I came up with 65 as at 6 drops it started to change but not completely, and at 7 drops it was changed completely. I am quite used to my 2106 kit and have a good feel. As far as the PH, not guessing, I was referring to how high to bring it back to after I found the sweet spot for my TA which is 65 ppm. Thanks for the input.

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I have had my tub for a week, so I am a newby and I am learning how to balance everything. I am using the 3 part bromine system, and I have been following waterbear's sticky. I bought a Taylor kit for bromine.

I've got a good handle on the bromine. It is mostly in range, and when it isn't I understand why and how to fix it.

My problem is with the TA and pH. I know I'm not supposed to worry about my TA, but it is already low. My tub is small at ~185 gallons. I started with a CH of 160, and I have not remeasured it. I have been using the tub heavily. One or two people ~40 minutes a day with aeration, so of course the pH is rising. I started with a high TA that I dropped to 90 with dry acid (overshot a bit). Over the course of the week,my pH has continued to rise, so I have added dry acid to lower it. I have been measuring my TA and it has gotten down to 50 and my pH is still rising. The pH has consistently read 8 using the Taylor kit, and adding a drop in the acid demand test has resulted in a pH of 7.0 yesterday then 7.2 this morning and now 7.4 tonight. If I add more dry acid, the pH will go down but so with the TA. I thought I wasn't supposed to go below 50. I don't have any of this borate stuff. It has only been a week, and my TA is already on the low end of the range. I guess I was expecting some kind of a sweet spot before now, or at least that it wouldn't have reached 50 so quickly. I have baking soda and Borax, but I don't have muriatic acid. I am wondering what I should do, and where I should go to find out how much of what to add. Thanks for any help.

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The small tub with daily extensive (40 minute) aeration is having the pH climb even with a TA of 50 ppm. I think you are a good candidate for using 50 ppm Borates. It may not cut down on how much acid you need to add, but it will slow the rate of pH rise (the pH rises less, but it takes more acid to lower it due to the borates). You would also target a higher pH of around 7.8 or so.

You can use dry acid instead of Muriatic Acid if you want. To get 50 ppm Borates in 185 gallons you would add about 10-1/2 ounces volume (11 ounces weight) of 20 Mule Team Borax and 4-3/4 ounces volume (7 ounces weight) of dry acid. Add half of each, starting with the Borax. You may need to adjust the pH a little at the end -- if it's too high then add a small amount of acid (say, 1/4 teaspoon) while if it's too low, just aerate the water.

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Confusion has set in so I apologise as this question has been asked and answered many different ways, however I’ll raise my concern regardless. I have my spa 4 weeks as of Dec 1 2012

I’m using a Taylor K-2006 test kit and my results are consistent with those from my dealer who tests my water. I follow my dealers’ instructions for adding chemicals to the water to control PH, however drift up always occurs in short order.

My PH continually rises quite a bit above 8.0, based on what it can take to get the PH to below 8 I’m guessing I may be as high as 8.4 at times.

Recently I noticed what I’m guessing is scale buildup in the spa. Dry powered feeling above and below the water line on spa surfaces that will rub off. The water however is crystal clear.

I want to ensure my PH remains between 7.2 and 7.8.

From what I’ve read on this forum it’s recommended that I lower my TA to a point below which my spa manufacturer and retailer recommend. I’ve been told that damage resulting from a TA below 100 is not covered under warranty. I’ve also read that a low TA can cause damage (corrosion) to the spa (acrylic) surface and jets (stainless, plastics and whatever) so the notion of lowering my TA below 100 scares me.

I have a swimming pool with a copper core heater. I have had corrosion issues with the heater and I don’t want to head down the same path with my new spa. I’m just making note of a bad experience with no real relevance to the spa issue (asides from me being a dumb ass).

My numbers typically are as follows for a 2,000L (528 gallon) tub at 101oF and I’m using Lithium as my sanitizer:

PH: 8.0+

TA: 100

Calcium / Hardness: 110

CY: 30

Sanitizer level is usually between 1 and 3 as I also use a UV system

Combined chlorine recently measured 0.8

TDS 600

I recently read that it would help keep my PH in check if I increase my calcium hardness to about 200ppm and adjust my TA to about 120. Can anyone please shed some light on my concern about low TA, provide insight on the recommendation that I was provided with respect to hardness, and or just point me in the right direction.

Very much appreciated :)

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