TA/CA Question

[wmarq]

Hello all

Brief history and then my question. Started with SWG , as years went by seemed like my coping stones were melting away, SWG died, switched to Trichlor not knowing anything about pool chemistry, 2yrs later have algae bloom that took enormous amounts of chlorine to kill and started noticing etching bottom of pool. That led me here. In reading forums and website I have learned a lot and this resource is invaluable. I have decided to do bleach/liquid chlorine this year to see how it goes. In trying to get chemistry to a point where it works for me it seems that (using LSI) my best move would be to run a low calcium pool. I know that is not necessarily advised on here so I thought I would ask for some thought/input on it from others. I had to dilute the water to get rid of the CYA and here is where I am starting from

Fill water:
TA 200
CH 50
CYA 30
TDS 300

Fresh Pool Reading:
TA 140
CH 100
PH OFF scale so 8.5? (I honestly don't know how to measure what it actually is when it goes off scale)
CYA 35

I never had an etching problem before the tablets. I did have hard scale buildup around the tile line. After diving into the forums and reading all that I could I have come to the assumption that a constant High TA has actually helped preserve the plaster? (When I ran SWG I was adding acid constantly to adjust PH as that s what the pool store instructed , but it would never stay down more than a day at a time and honestly I was just too busy and neglected it so the PH was constantly too high for years) When I started using the pucks I was so happy PH stayed in line and I never investigated why.

The heart of the question is looking at these LSI readings I can run this water at TA75 CH 100 CYA 30 PH 8.2 , have a wide swing in Temperatures and still never have unbalanced water. Is it ok to run this water that low on ch and ta here in east Texas? I mean If I do that my main adjustment would seem to be beating the TA back down as it rises from the fill water that I put in(wonder how long that takes). Or maybe I should keep running the super high TA like I was doing with SWG and just let it go. It sure seems like that protected my plaster because I have no CH from tap and I have never put any in and never saw a problem still I started using the pucks. Pool is 17 years old now. I can muscle off the scale and would rather do that than lose my plaster (any more of it) but if I can lower that alkalinity (which I am thinking helped protect the plaster, but I certainly don't know that for sure) I could keep the PH way more in check. If I started raising the calcium to compensate for lower TA , when temperatures start to rise I will be scaling again, so my thinking is forget the calcium (never put in in before anyway ) and let the TA run high and deal with that. Anyone have any advice? Can I run both of those reading that low without damage the plaster. The LSI calculator certainly says that I can but I haven't seen anyone on here or anywhere else that would suggest that. If I can't , why not , and why does the calculator say that you can ? Sorry so long here , but I guess the context is important.

 

[rack04]

First of all, what test kit are you using? The recommended test kits don't report TA in increments of 5. Here are the TFP recommended test kits.

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why not use test strips? Our recommended test kits will pay for themselves in no time!

www.troublefreepool.com

Your fill water does not have CYA.

My advice is not hyper focus on Langelier Saturation Index (LSI) and in fact consider Calcium Saturation Index (CSI) over LSI. Read through this article, specifically the part about not stressing if your CSI falls out of the “safe range” as it takes time for any problems to occur.

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

 

[Jimrahbe]

W,

Your coping is not melting away because you had a SWCG, it is melting away because that want happens to cheap Texas stone.. Here is my 'story'..

Roughly 15 years ago, I bought a HUD house with a pool. Both the pool and the house needed plenty of work. I had the pool replastered, new tile and Flagstone coping installed. This was my first pool and I had no idea what I was doing.

I used chlorine tablets for the first few years. During this time the flagstone coping would constantly shed thin layers of sand.. This started almost immediately after the coping was installed. The coping had good stones and bad stones, often right next to each other. This went on for 2 or 3 years and I then found TFP and converted to a SWCG. The pool has been saltwater for over 12 years years now and the bad stones still shed, and the good ones do not. If anything, it seems like the shedding has slowed down.

The take-away is that saltwater is not the problem, it is the stone.

I now have three saltwater pools and none of them have any negative issues due to being saltwater. I'd just as soon fill them in with dirt as not have them be saltwater pools.

Thanks,

Jim R.

 

[wmarq]

First of all, what test kit are you using? The recommended test kits don't report TA in increments of 5. Here are the TFP recommended test kits.

Swimming Pool Test Kits Compared

What pool test kit should I buy? Why not use test strips? Our recommended test kits will pay for themselves in no time!

www.troublefreepool.com

Your fill water does not have CYA.

My advice is not hyper focus on Langelier Saturation Index (LSI) and in fact consider Calcium Saturation Index (CSI) over LSI. Read through this article, specifically the part about not stressing if your CSI falls out of the “safe range” as it takes time for any problems to occur.

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

im sorry about that , was a typo , I have the most expensive kit recommend from this website with the mixer. don't remember the number on the kit , 2600 maybe? I don't have it with me currently

 

[wmarq]

W,

Your coping is not melting away because you had a SWCG, it is melting away because that want happens to cheap Texas stone.. Here is my 'story'..

Roughly 15 years ago, I bought a HUD house with a pool. Both the pool and the house needed plenty of work. I had the pool replastered, new tile and Flagstone coping installed. This was my first pool and I had no idea what I was doing.

I used chlorine tablets for the first few years. During this time the flagstone coping would constantly shed thin layers of sand.. This started almost immediately after the coping was installed. The coping had good stones and bad stones, often right next to each other. This went on for 2 or 3 years and I then found TFP and converted to a SWCG. The pool has been saltwater for over 12 years years now and the bad stones still shed, and the good ones do not. If anything, it seems like the shedding has slowed down.

The take-away is that saltwater is not the problem, it is the stone.

I now have three saltwater pools and none of them have any negative issues due to being saltwater. I'd just as soon fill them in with dirt as not have them be saltwater pools.

Thanks,

Jim R.

I should consider switching back to swg then .....I hear you run cya higher in that scenario , is that true?

 

[wmarq]

W,

Your coping is not melting away because you had a SWCG, it is melting away because that want happens to cheap Texas stone.. Here is my 'story'..

Roughly 15 years ago, I bought a HUD house with a pool. Both the pool and the house needed plenty of work. I had the pool replastered, new tile and Flagstone coping installed. This was my first pool and I had no idea what I was doing.

I used chlorine tablets for the first few years. During this time the flagstone coping would constantly shed thin layers of sand.. This started almost immediately after the coping was installed. The coping had good stones and bad stones, often right next to each other. This went on for 2 or 3 years and I then found TFP and converted to a SWCG. The pool has been saltwater for over 12 years years now and the bad stones still shed, and the good ones do not. If anything, it seems like the shedding has slowed down.

The take-away is that saltwater is not the problem, it is the stone.

I now have three saltwater pools and none of them have any negative issues due to being saltwater. I'd just as soon fill them in with dirt as not have them be saltwater pools.

Thanks,

Jim R.

also I would love to hear about your high ph problems if any , when I ran that swg it seemed like it needed acid every day , but maybe that's because of the alkaline water idk

 

[Jimrahbe]

W,

You should pick the sanitation you want.. Whatever works for you, works for me.. I was just trying to point out that I doubt the SWCG had anything to do with damaging your coping... Try chlorine tablets and see if it makes any difference.

We recommend a CYA of 60 or 70 when you have a saltwater pool.. I do not see this as any kind of problem, do you??

I add about 30 oz. of muriatic acid (MA) about once a week or less. This keeps my pH between 7.5 and 7.8.. This take me about 5 minutes, so I don't see this as too burdensome..

I also keep my TA at about 50 or 60 and this helps keep the pH in check...

Thanks,

Jim R.

 

[wmarq]

W,

Your coping is not melting away because you had a SWCG, it is melting away because that want happens to cheap Texas stone.. Here is my 'story'..

Roughly 15 years ago, I bought a HUD house with a pool. Both the pool and the house needed plenty of work. I had the pool replastered, new tile and Flagstone coping installed. This was my first pool and I had no idea what I was doing.

I used chlorine tablets for the first few years. During this time the flagstone coping would constantly shed thin layers of sand.. This started almost immediately after the coping was installed. The coping had good stones and bad stones, often right next to each other. This went on for 2 or 3 years and I then found TFP and converted to a SWCG. The pool has been saltwater for over 12 years years now and the bad stones still shed, and the good ones do not. If anything, it seems like the shedding has slowed down.

The take-away is that saltwater is not the problem, it is the stone.

I now have three saltwater pools and none of them have any negative issues due to being saltwater. I'd just as soon fill them in with dirt as not have them be saltwater pools.

Thanks,

Jim R.

also I would love to hear about your high ph problems if any , when I ran that swg it seemed like it needed acid every day , but maybe that's because of the alkaline water idk

W,

You should pick the sanitation you want.. Whatever works for you, works for me.. I was just trying to point out that I doubt the SWCG had anything to do with damaging your coping... Try chlorine tablets and see if it makes any difference.

We recommend a CYA of 60 or 70 when you have a saltwater pool.. I do not see this as any kind of problem, do you??

I add about 30 oz. of muriatic acid (MA) about once a week or less. This keeps my pH between 7.5 and 7.8.. This take me about 5 minutes, so I don't see this as too burdensome..

I also keep my TA at about 50 or 60 and this helps keep the pH in check...

Thanks,

Jim R.

what do you keep calcium at ? I liked the SWG , just had to adjust salt when we get a hard rain but that s all , was pretty easy

 

[Jimrahbe]

W,

I pretty much use the TFP standards in this link...

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com

Thanks,

Jim R.

 

[wmarq]

W,

I pretty much use the TFP standards in this link...

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com

Thanks,

Jim R.

thanks a lot for all the info

 

[reggiehammond]

You should test your fill water - mine is very high TA. High TA fill water causes pH to rise, necessitating acid additions.

VERY common in Texas. Once TA has been knocked down to ~50, pH will stop rising, but any high fill water will raise TA, causing you to need more acid.

I couldn't live without a SWCG and I also have an acre of flagstone - but it fails the same next to the pool as it does a few hundred yards away.

 

[wmarq]

You should test your fill water - mine is very high TA. High TA fill water causes pH to rise, necessitating acid additions.

VERY common in Texas. Once TA has been knocked down to ~50, pH will stop rising, but any high fill water will raise TA, causing you to need more acid.

I couldn't live without a SWCG and I also have an acre of flagstone - but it fails the same next to the pool as it does a few hundred yards away.

Wow can you tell me what calcium level you run? I was looking at that dang LSI index and it tells me I gotta run low calcium to keep that lsi right…my fill water is 200 TA. How much acid do you go through, I mean are you adding daily or maybe 2 ,3 times a week ?

 

[rack04]

Wow can you tell me what calcium level you run? I was looking at that dang LSI index and it tells me I gotta run low calcium to keep that lsi right…my fill water is 200 TA. How much acid do you go through, I mean are you adding daily or maybe 2 ,3 times a week ?

CSI and LSI are more influenced by PH, CH, and water temperature. Using your readings from the first post PH 8.5 TA 140 CH 100 CYA 35 your CSI is 0.46. I assumed your pool water temperature was similar to mine in Plano 67.1 degrees F. Lowering your PH to 7.8 would result in a CSI of -0.23 which would be within the reasonable TFP range -0.3 to 0.3. What is your hesitation to run high PH and low CH? Also, CY 35 isn't a graduation in the recommended test kits. You should assume 40 for chlorine dosing.

I generally keep CH low because during the summer with water additions the CH will build based on my fill water. I adjust PH based on the water temperature. PH is the easiest thing to chase, especially when you get your TA down to 50-70.

Here are my current readings for comparison:

PH 7.6
TA 70
CH 350
CYA 50
FC 9
CC 0
Salt 2000
Temp 67.1
CSI -0.27

 

[reggiehammond]

Wow can you tell me what calcium level you run? I was looking at that dang LSI index and it tells me I gotta run low calcium to keep that lsi right…my fill water is 200 TA. How much acid do you go through, I mean are you adding daily or maybe 2 ,3 times a week ?

I manage my TA down early in the summer then need to add a gallon of acid for every 1” of water I have to add for evaporation.
You need to track CSI in pool math. Download the app and pay the $7 yearly if not already using it.

My CH is normally in the 400’s. It’s just a part of the overall system, though.

 

[wmarq]

I appreciate all the responses here, helpful info and I will use it , thank you