Lowering PH

[cacciato2006]

The TA will come down for free as you manage the pH to stay in the 7’s.

TA will not come down because the feed water TA has tested twice at 330 and 350.

 

[cacciato2006]

Where are you in Texas? Update your profile when able.

Palestine Texas. Done

 

[AlexPowell]

If your fill water is 350 TA then you'll just be having to regularly add acid to bring the pH down.

Your CSI is not bad and a TA of 240 is not problematic. To drop your pool to a TA of 80 from 240 in a 30,000 gallon pool is probably not even possible as TA will increase from evaporation refill faster than it is removed from acid/aeration. It would also take an unholy amount of muriatic acid.

I personally would just be dropping the pool down to 7.4 once a week and being done with it

 

[cacciato2006]

If your fill water is 350 TA then you'll just be having to regularly add acid to bring the pH down.

Your CSI is not bad and a TA of 240 is not problematic. To drop your pool to a TA of 80 from 240 in a 30,000 gallon pool is probably not even possible as TA will increase from evaporation refill faster than it is removed from acid/aeration. It would also take an unholy amount of muriatic acid.

I personally would just be dropping the pool down to 7.4 once a week and being done with it

What do you think about installing a 300 GPD RO system or larger on the feed line to the pool? I dosed the pool last night with 2 gallons of 31.45% MA. The PH went from 8.1 to 7.2 and the TA 240 to 190. I can't imagine having to do that every week.

 

[PoolStored]

I dosed the pool last night with 2 gallons of 31.45% MA. The PH went from 8.1 to 7.2 and the TA 240 to 190. I can't imagine having to do that every week.

I would be surprised, if you used the "Lowering Total Alkalinity" method to get your TA down to 60-80, that you can't get the MA additions to be manageable, even with some water replacement. I would try that FIRST, before you go out and buy an RO. Take the few days it takes to get it down, then see what happens.

Do you have a solar cover? With a solar cover, you will greatly reduce evaporation, which will lead to fewer additions, and make it even more manageable. How long after lower to 190 did it take for pH to rise. You may be able to quickly lower your TA.

I guess the point I'm making is that you are fighting a rapidly rising pH because TA is so high. Kinda like drinking from a firehose. If you lower TA, pH rise will be more like drinking from a water hose. Even if your fill water is high TA, you are not making 50% of the pool additions on a daily basis. The only MA you would be adding would be to lower the "bit" of TA added by the fill water.

I'd spend the 200$ on the cover, be aggressive with the TA lowering, then manage it for a few weeks. You may find it palatable.

 

[cacciato2006]

I would be surprised, if you used the "Lowering Total Alkalinity" method to get your TA down to 60-80, that you can't get the MA additions to be manageable, even with some water replacement. I would try that FIRST, before you go out and buy an RO. Take the few days it takes to get it down, then see what happens.

Do you have a solar cover? With a solar cover, you will greatly reduce evaporation, which will lead to fewer additions, and make it even more manageable. How long after lower to 190 did it take for pH to rise. You may be able to quickly lower your TA.

I guess the point I'm making is that you are fighting a rapidly rising pH because TA is so high. Kinda like drinking from a firehose. If you lower TA, pH rise will be more like drinking from a water hose. Even if your fill water is high TA, you are not making 50% of the pool additions on a daily basis. The only MA you would be adding would be to lower the "bit" of TA added by the fill water.

I'd spend the 200$ on the cover, be aggressive with the TA lowering, then manage it for a few weeks. You may find it palatable.

I posted the source water info earlier but on top of 340 TA, the PH is 8.1. Maybe I'm just panicked because I'm new to pools but it will likely be impossible to keep this pool swimmable during the summer without adding MA two or three times a week. I don't have a solar cover and its odd shaped pool but maybe that doesn't make a difference. I'll check the PH in the morning and see what the increase is. It was 7.3 last measured. I appreciate you comment.

 

[AlexPowell]

What do you think about installing a 300 GPD RO system or larger on the feed line to the pool? I dosed the pool last night with 2 gallons of 31.45% MA. The PH went from 8.1 to 7.2 and the TA 240 to 190. I can't imagine having to do that every week.

It would be cheaper to put in a rainwater tank and fill from that

 

[PoolStored]

I posted the source water info earlier but on top of 340 TA, the PH is 8.1. Maybe I'm just panicked because I'm new to pools but it will likely be impossible to keep this pool swimmable during the summer without adding MA two or three times a week. I don't have a solar cover and its odd shaped pool but maybe that doesn't make a difference. I'll check the PH in the morning and see what the increase is. It was 7.3 last measured. I appreciate you comment.

POP! (pool owner patience) Sometime the best answer isn't easy in the short term, but best in the long term. Spending 600$ is a reaction. Remember pH rise is fastest with HIGH TA and/or LOW pH. You lowered it to 7.3 and 190. That is low pH and HIGH TA. IT IS GOING TO RISE QUICKLY. However, if you employ some focussed patience and apply the lower total alkalinity and get it down to 60-80, and let your pH settle, you may find pH very stable. In that position, the ONLY TA you will be addressing is the addition of 340 to the pool. I would be surprised, especially with a cover, that your additions are going to be significant.

You have a 113,000 liter pool. With a TA of 80, that is 80ppm= 1mg/l, so 80mg/l * 113,000l = 9 Million mg = 9 kg TA
You add 1" in a week, that would be about 500 gallons = 1892 liters of 340ppm = .6 kg TA

Same pool volume in reverse 9.6kg TA = 9,600,000 mg / 113,000 l = 84.95.

So, figure out how much MA you would have to add if you added 500 gallons (1" of evaporation) to the pool, to reduce back to 80. Not much, about 32 ounces or so.

 

[cacciato2006]

POP! (pool owner patience) Sometime the best answer isn't easy in the short term, but best in the long term. Spending 600$ is a reaction. Remember pH rise is fastest with HIGH TA and/or LOW pH. You lowered it to 7.3 and 190. That is low pH and HIGH TA. IT IS GOING TO RISE QUICKLY. However, if you employ some focussed patience and apply the lower total alkalinity and get it down to 60-80, and let your pH settle, you may find pH very stable. In that position, the ONLY TA you will be addressing is the addition of 340 to the pool. I would be surprised, especially with a cover, that your additions are going to be significant.

You have a 113,000 liter pool. With a TA of 80, that is 80ppm= 1mg/l, so 80mg/l * 113,000l = 9 Million mg = 9 kg TA
You add 1" in a week, that would be about 500 gallons = 1892 liters of 340ppm = .6 kg TA

Same pool volume in reverse 9.6kg TA = 9,600,000 mg / 113,000 l = 84.95.

So, figure out how much MA you would have to add if you added 500 gallons (1" of evaporation) to the pool, to reduce back to 80. Not much, about 32 ounces or so.

So, the next step would be to wait for the PH to creep up and then hit it with MA and aerate and then repeat and repeat until TA is 80? Right now we are not getting a lot of evaporation so I should be able to hit that TA eventually.

 

[PoolStored]

So, the next step would be to wait for the PH to creep up and then hit it with MA and aerate and then repeat and repeat until TA is 80? Right now we are not getting a lot of evaporation so I should be able to hit that TA eventually.

If your additions are accurate, and want this to go faster, drive pH to 7.0. When it gets to 7.4, drive it back to 7.0. CO2 outgasses at the highest rate between 7.0 and 7.4. Will be more frequent additions but will go faster. I also wouldn't hesitate to take TA down to 60, given your TA fill. Just never let TA get below 50. I keep mine at 60 and my pH SITS at 7.4 all year, no MA additions. My fill water is 70 however. I just think that if you get your body of water down to 60, you will find your water additions manageable with MA. Without doing backflips and spending a bunch of $$ on RO. TFP.

If I am wrong, you are nothing out of pocket until then. You would still use the MA to get TA down.

Last note, again, remember CO2 outgasses faster at high TA and low pH. You will find, that over the course of your repeats, early the pH will rise faster. As you get closer to TA=60, the pH rise will slow. Like I said, takes me 12 hours with my rig. I went from 140 to 70 in three days, using the 7.0-7.4 cycle, same size pool. If your water features don't raise pH from 7.0 to 7.4 in 12 hours, you may consider building a rig like I showed before. All depends on the aeration of your features. LOTS of SMALL bubble work best.

 

[cacciato2006]

If your additions are accurate, and want this to go faster, drive pH to 7.0. When it gets to 7.4, drive it back to 7.0. CO2 outgasses at the highest rate between 7.0 and 7.4. Will be more frequent additions but will go faster. I also wouldn't hesitate to take TA down to 60, given your TA fill. Just never let TA get below 50. I keep mine at 60 and my pH SITS at 7.4 all year, no MA additions. My fill water is 70 however. I just think that if you get your body of water down to 60, you will find your water additions manageable with MA. Without doing backflips and spending a bunch of $$ on RO. TFP.

If I am wrong, you are nothing out of pocket until then. You would still use the MA to get TA down.

Last note, again, remember CO2 outgasses faster at high TA and low pH. You will find, that over the course of your repeats, early the pH will rise faster. As you get closer to TA=60, the pH rise will slow. Like I said, takes me 12 hours with my rig. I went from 140 to 70 in three days, using the 7.0-7.4 cycle, same size pool. If your water features don't raise pH from 7.0 to 7.4 in 12 hours, you may consider building a rig like I showed before. All depends on the aeration of your features. LOTS of SMALL bubble work best.

I was looking at solar covers on youtube to maybe reduce the evaporation. They make the water hotter and we don't need that here in Texas and it cost as much as the 300 GPD RO system. I'll get the TA down as you described above and see how much MA I'm adding long term. I think I can buy it in 55 gallon drum. haha

 

[PoolStored]

I was looking at solar covers on youtube to maybe reduce the evaporation. They make the water hotter and we don't need that here in Texas and it cost as much as the 300 GPD RO system. I'll get the TA down as you described above and see how much MA I'm adding long term. I think I can buy it in 55 gallon drum. haha

Yeah, I had a response on the cover and then decided not to send because of the heat issue. If you do go that route, don't spend more than $200. Even a rectangle cover, uncut that fits would reduce evap. You don't need anything over 8mil. More is not better with these.

I don't think you are going to need anything near 55 drum. Just get the TA down and when you get there, accept a pH of 7.8, 8.0 or even 8.2 and I think you will find it to be fairly stable and can manage water additions. Even at TA60, if you drive pH down to 7.2/4/6 you will have that rise. Get it to 60 and let pH be where it may, even up to 8.2 and don't constantly fight it (lower it).

 

[Bperry]

TA will not come down because the feed water TA has tested twice at 330 and 350.

Yes it will. You’re not adding 1000’s of gallons of fill water very often. The natural pH rise will require you to keep adding acid to manage it and it’ll slow down as your TA lowers.

 

[Bperry]

Maybe I'm just panicked because I'm new to pools but it will likely be impossible to keep this pool swimmable during the summer without adding MA two or three times a week.

I suspect that’s it, but don’t panic. It’s totally normal for a pool to require acid additions at least once a week and even multiple times especially when they are new. After a while it’ll slow down. You can swim either way as the TA has nothing to do with whether the pool is swimmable. You only care about pH, FC, CYA for “swim-able” status.

 

[pjt]

TA will not come down because the feed water TA has tested twice at 330 and 350.

I have similar fill water here (TA 330). If you're using lots of fill water due to evaporation, you'll be constantly fighting high TA. I try to maximize clean rainwater and minimize using fill water. I haven't needed fill water since October, so I've been able to get my TA down to ~60. My pH rise is almost nothing.

 

[cacciato2006]

Just get the TA down and when you get there, accept a pH of 7.8, 8.0 or even 8.2 and I think you will find it to be fairly stable and can manage water additions

when I google it says for swimming 8.0 is the maximum or people could get rashes. Our tap water measures 8.1 and we don't get rashes showering so I'm not sure what the absolute maximum really is. Do you have any thoughts?

 

[cacciato2006]

I have similar fill water here (TA 330). If you're using lots of fill water due to evaporation, you'll be constantly fighting high TA. I try to maximize clean rainwater and minimize using fill water. I haven't needed fill water since October, so I've been able to get my TA down to ~60. My pH rise is almost nothing.

I've lowered the fill float to see if I can get the water level down while keeping in mind the skimmers. The float this morning was so high I was loosing a little bit of water out of the high drain. If I can get it down a little I'm likely to catch more rain water and store it.

 

[PoolStored]

when I google it says for swimming 8.0 is the maximum or people could get rashes. Our tap water measures 8.1 and we don't get rashes showering so I'm not sure what the absolute maximum really is. Do you have any thoughts?

The pH of human skin is normally acidic at a pH of around 5.4 to 5.9 (see this link and this link) so having the pool be unusually acidic isn't likely to cause a problem to skin unless it's much more acidic, such as in pools that use Trichlor without adjustment that get down to a pH of 4.5 or lower (i.e. they immediately show red on the TA test). Generally, it takes a fairly low pH below 3 to cause itching -- lemon juice is around a pH of 2.3 and if put on your skin and left to dry you will probably find that it itches.

Alkaline soap has a pH around 9-10 but can feel slippery on skin rinsed in soft water as some of the soap remains on the skin. If the pH is higher, such as found with lye (13 or higher) or undiluted bleach (11.9 or higher) or chlorinating liquid (12.5 or higher), the oils in your skin saponify which basically turns fats and oils in your skin to soap which is why it feels slippery.

So generally speaking, a pH range of 7.2 to 8.2 isn't going to do very much with your skin unless you have very unusual sensitivities. Tap water is usually in the pH range of 7.5 to 8.0 (yours is 8.1) and is intentionally made more alkaline than neutral in order to reduce metal corrosion.

Your eyes, on the other hand, are more sensitive to pH changes in the water, but still not that sensitive at least to pH. The pH of human tears varies somewhat but averages 7.5 (see this link while this one says the average is 7.0[END-EDIT]). This paper talks about various factors affecting eye irritation in swimming pools. The primary factor for irritation appeared to be osmotic pressure since adding salt to the water at around 0.5% (around 5000 ppm) in the field study or 0.7% (around 7000 ppm) in the lab study virtually eliminated the irritation which isn't much of a surprise since the salinity of human tears is around 9000 ppm. The pH varying from 7 to 9 did not show a significant difference in irritation. A 1975 paper by Eichelsdoerfer, which I can't find, describes how the chloramines can be more irritating. Other studies show that nitrogen trichloride (see this link among many others) can be particularly irritating. PH below 7.2 causes many people to feel some rather mild stinging of their eyes and PH in the low 6s or lower can result in some skin itching and somewhat worse stinging of your eyes.

When there is no CYA in the water, then the production of volatile and irritating nitrogen trichloride is much more prevalent, especially with higher bather (or other organic) loads. Also, it is very dependent on the pH where far more is produced at lower pH (from a pH of 8.0 to 7.0 and with no CYA the amount of nitrogen trichloride increases by a factor of 4.3 whereas the active chlorine level increased by a factor of 3.4). So I strongly suspect that the main correlation with eye irritation as well as "bad pool chlorine" smell, coughing and other problems is mostly associated with nitrogen trichloride and that at lower pH more is produced. It isn't the pH of the water itself that is the problem, but rather the effects on the chemistry of what is produced at the lower pH. In pools with CYA in the water, especially in residential pools that typically have low bather load, I suspect that preventing moderate changes in the pH are more important for protection of plaster surfaces and to prevent metal corrosion than for prevention of irritation of the human body.

(Full cite on Eichelsdoerfer paper: Eichelsdoerfer, D., Slovak, J., Dirnagl, K., Schmid, K., 1975. Irritant effect (conjunctivitis) of chlorine and chloramines in swimming pool water. Vom Wasser, 45, 17-28 (translated).

 

[cacciato2006]

Spent most of the day at the pool running the spa pump to generate bubbles and the waterfall to get the splash back into the pool.
Early this morning:
TA was 190, PH rose from 7.3 to 7.7 overnight.
I started dosing small amounts of MA every hour with at least another gallon or more going in.

By this afternoon:
PH is 7.1 and TA is 150.
I left the spa and filter pump running all night and we will see where we are in the morning.
I have two more gallons of 31% MA and I'm hoping that gets me close over the next few days to 60.

In the morning I'll test Ph and TA and see where we are at.
CSI is currently -0.68 which is less than the suggested -0.60 but not too far off.

Another question:
When I purchased the home/pool (plaster) and tested the hardness it was 100. I added in 25lbs of calcium and it is now 175. Last I tested the tap water it has CH of 50. Do I go ahead and bump it up or do I just let the fill water push it up? My gut says get it to at least 300 now.

CYA is 48. Fc is 3.0. Target should be 6.0. I've only been adjusting one thing at a time. Right now I've been working on TA, Next Fc and then CH or does it matter? Can I just start adding in chlorine and calcium now or should I wait?
Thanks,

The pH of human skin is normally acidic at a pH of around 5.4 to 5.9 (see this link and this link) so having the pool be unusually acidic isn't likely to cause a problem to skin unless it's much more acidic, such as in pools that use Trichlor without adjustment that get down to a pH of 4.5 or lower (i.e. they immediately show red on the TA test). Generally, it takes a fairly low pH below 3 to cause itching -- lemon juice is around a pH of 2.3 and if put on your skin and left to dry you will probably find that it itches.

Alkaline soap has a pH around 9-10 but can feel slippery on skin rinsed in soft water as some of the soap remains on the skin. If the pH is higher, such as found with lye (13 or higher) or undiluted bleach (11.9 or higher) or chlorinating liquid (12.5 or higher), the oils in your skin saponify which basically turns fats and oils in your skin to soap which is why it feels slippery.

So generally speaking, a pH range of 7.2 to 8.2 isn't going to do very much with your skin unless you have very unusual sensitivities. Tap water is usually in the pH range of 7.5 to 8.0 (yours is 8.1) and is intentionally made more alkaline than neutral in order to reduce metal corrosion.

Your eyes, on the other hand, are more sensitive to pH changes in the water, but still not that sensitive at least to pH. The pH of human tears varies somewhat but averages 7.5 (see this link while this one says the average is 7.0[END-EDIT]). This paper talks about various factors affecting eye irritation in swimming pools. The primary factor for irritation appeared to be osmotic pressure since adding salt to the water at around 0.5% (around 5000 ppm) in the field study or 0.7% (around 7000 ppm) in the lab study virtually eliminated the irritation which isn't much of a surprise since the salinity of human tears is around 9000 ppm. The pH varying from 7 to 9 did not show a significant difference in irritation. A 1975 paper by Eichelsdoerfer, which I can't find, describes how the chloramines can be more irritating. Other studies show that nitrogen trichloride (see this link among many others) can be particularly irritating. PH below 7.2 causes many people to feel some rather mild stinging of their eyes and PH in the low 6s or lower can result in some skin itching and somewhat worse stinging of your eyes.

When there is no CYA in the water, then the production of volatile and irritating nitrogen trichloride is much more prevalent, especially with higher bather (or other organic) loads. Also, it is very dependent on the pH where far more is produced at lower pH (from a pH of 8.0 to 7.0 and with no CYA the amount of nitrogen trichloride increases by a factor of 4.3 whereas the active chlorine level increased by a factor of 3.4). So I strongly suspect that the main correlation with eye irritation as well as "bad pool chlorine" smell, coughing and other problems is mostly associated with nitrogen trichloride and that at lower pH more is produced. It isn't the pH of the water itself that is the problem, but rather the effects on the chemistry of what is produced at the lower pH. In pools with CYA in the water, especially in residential pools that typically have low bather load, I suspect that preventing moderate changes in the pH are more important for protection of plaster surfaces and to prevent metal corrosion than for prevention of irritation of the human body.

(Full cite on Eichelsdoerfer paper: Eichelsdoerfer, D., Slovak, J., Dirnagl, K., Schmid, K., 1975. Irritant effect (conjunctivitis) of chlorine and chloramines in swimming pool water. Vom Wasser, 45, 17-28 (translated).

I appreciate you information. I won't worry about too much it would seem.

 

[PoolStored]

When I purchased the home/pool (plaster) and tested the hardness it was 100. I added in 25lbs of calcium and it is now 175. Last I tested the tap water it has CH of 50. Do I go ahead and bump it up or do I just let the fill water push it up? My gut says get it to at least 300 now.

I would either leave it alone or get it to 200 if you are super concerned and it will help you sleep better. Your plaster will be fine. Starting at a lower number will hold off the refill with CH in your fill.

CYA is 48. Fc is 3.0. Target should be 6.0. I've only been adjusting one thing at a time. Right now I've been working on TA, Next Fc and then CH or does it matter? Can I just start adding in chlorine and calcium now or should I wait?

Your CYA is 50. We only measure at the lines, not in-between. It is a log scale, so only lines. GET THAT FC UP NOW. Minimum and below is LAVA. Get some liquid chlorine in today. FC IS A DAILY test and replenish. You may be ok, because the water is cold, but always FC is your primary concern. All others have secondary effects...i.e. primary effect of low FC is algae. pH, TA, CH, CYA can go a day and it won't matter. FC matters.
You can do TA/FC/CH all at the same general time. Just give it 15-30 minutes between MA and liquid chlorine. Never these two together.