Total alkalinity question (and my filter war)

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J

Jake&Clan

Active member
Jun 17, 2022
44
Cedarville, Ohio
Pool Size
13000
Surface
Vinyl
Chlorine
Liquid Chlorine
13k above ground, pH 7.5, FC 10.0, CYA 60

Apparently I have too much time on my hands this year because I have decided to wage the ever-ending war against my insanely High total alkalinity. It's sitting somewhere between 220 and 250. I use the TF 100 test kit like everybody else and it's amazing. I just don't know, when it says turn red, is it talking about when it just starts to turn a little pink.. a little bit more pink.. magenta.. fire engine red? That's not my main question that's a sidebar.

The pool math app does not tell you how much muriatic acid to add when you click on the results from your total alkalinity test. It just says use acid to bring it down and aerate to bring the pH back up. A general Google search tells me that in a 10,000 gallon pool I need approximately 25.6 oz of MA to lower my total alkalinity 10 parts per million. With trying to get my total alkalinity down to 90 that is a staggering 11 times 25.6 ounces. We're talking a coupe GALLONS of MA.

That said, I do have that much muriatic acid here. There's just red flags and alarm Bells whistles and alerts going off in my head about dumping 2 gallons of muriatic acid into this pool right now. I can't imagine how much it'll bottom out the ph. On a good note, the pool is not swimmable at this point. We just opened 3 days ago. I'm dealing with a bit of an algae bloom issue and I am getting it under control but my chlorine levels are north of 10 while my big ole DE filter (Hayward Ec40Ac, takes 4lb of DE) and pump continue to slave away at clearing it out. It appears most of the algea is dead (I think) which is great, but I'm having to bump my DE filter every 4 hours or so plus backwash a couple times in just a few days and deep clean the fingers out. Chlorine is too high to run the robot cleaner. I'm winning the battle on that front but I'm just a little confused on the total alkalinity.

Regarding my filter War here's how this is playing out. This filter is starting out at around 8:00 psi. That was as of 2:30 this morning. By 8:30 this morning that sucker went up 10 psi. This is after I completely deep cleaned all of the fingers last night. I mean this thing was squeaky clean. I was shocked. I can't understand how this pool filter is getting up in PSI so darn fast. I've been running this thing hard for 3 days so this LG really is under pretty good control at this point. The water is clearing up a lot and most of the stuff is just dead on the bottom. My chlorine levels dropped six part per million, though, from yesterday morning to this morning so maybe that's indicative of still some live algae? Keep in mind this pool is sitting in Broad sunlight every hour of the day and we're hitting 90° here in Southwest Ohio which is unusual for this time of year.

As usual I'm checking the pump religiously and bumping it as needed. It hqw gone up 1psi from 10:20am to 11:50 today so 1.5 hours. This morning it went up 2 psi in 2:10.


I can't figure out if there's another issue here other than the filter just getting full. I mean there's 4lb of DE in there... That gas been back washed twice and the filter deep cleaned once 20230602_114905.jpg20230602_114856.jpg20230602_114942.jpg20230602_114936.jpg


Thanks
 
Last edited:
TA is not your problem now...you need to slam to get rid of algae. Link-->SLAM Process

Focus on the SLAM, ignore TA for now.

When you finish slam, here is the TA info.
www.troublefreepool.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.
www.troublefreepool.com www.troublefreepool.com
 
PoolStored said:
TA is not your problem now...you need to slam to get rid of algae. Link-->SLAM Process

Focus on the SLAM, ignore TA for now.

When you finish slam, here is the TA info.
www.troublefreepool.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.
www.troublefreepool.com www.troublefreepool.com
Click to expand...

I've got no way to aerate. Have to use chemicals which brings TA up. What's the quickest and easiest way to aerate?
 
mknauss said:
What are those?
Click to expand...

mknauss said:
What are those?
Click to expand...
Sodium carbonate

It is extremely rare for me to have to raise my pH. Pool store says that adding chlorine is not supposed to affect my pH but I use a ridiculous amount of chlorine throughout the summer and every time I do my pH goes up. Maybe it's not related. Until the end of last year I was using sodium bisulfate to lower pH but after doing research decided to go back to using muriatic acid. I don't really like muriatic acid for the obvious reason of just how nasty the stuff is but it's impact on total alkalinity and effectiveness on ph seems to be better
 
Your pH rises because of your TA level, not chlorine.

You can lower your total alkalinity. Get it to 60-80 and your pH rise will slow.

www.troublefreepool.com

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.
www.troublefreepool.com www.troublefreepool.com
 
Jake&Clan said:
I've got no way to aerate. Have to use chemicals which brings TA up. What's the quickest and easiest way to aerate?
Click to expand...

Aeration is the only way to raise pH without raising TA at the same time. Any chemical you add to raise pH will also raise TA, and will make the initial acid addition to lower TA together with pH pointless.

The purpose of aeration is to speed up CO2 outgassing which is what raises the pH. Like in soda water - when you let the bubbles bubble out, the water tastes less acidic.

If you can't aerate, then just wait, outgassing is happening on its own, just a little slower. Follow the process linked above once your algae is under control.

Jake&Clan said:
I just don't know, when it says turn red, is it talking about when it just starts to turn a little pink.. a little bit more pink.. magenta.. fire engine red?
Click to expand...

You have reached the endpoint of the titration when another drop doesn't change the colour further. If there is for example still a change to a more intense colour between 13 and 14 drops, but no further change with the 15th drop, then 14 is your drop count.

Jake&Clan said:
It is extremely rare for me to have to raise my pH. Pool store says that adding chlorine is not supposed to affect my pH but I use a ridiculous amount of chlorine throughout the summer and every time I do my pH goes up
Click to expand...

The complete chlorination cycle with liquid chlorine is pH neutral. Adding liquid chlorine initially raises pH, the following "use" of chlorine (i.e chlorine doing its job as a sanitiser/oxidiser and getting deactivated by UV light) is an acidic process and compensates the initial pH rise once the FC level is back to where it was before the liquid chlorine addition.

During normal pool maintenance, i.e smallish daily chlorine additions to maintain target FC, the pH fluctuations are so small that you will hardly notice them with standard pool kit testing. You will only really notice the overlaying pH drift from CO2 outgassing.

But when adding a larger amount to go from zero to slam for example, the effect is more pronounced. That's why the slam process asks you to reduce pH before adding chlorine.

Also keep in mind that from FC about 10ppm, chlorine interferes with the pH test, making it look like high pH even if it's not. Another reason for adjusting pH before a slam, because you're blind to pH during the slam.

For now, deal with your algae by starting to slam, then deal with your TA.
 
Donldson said:
Why are you using sodium carbonate in your water if your pH and TA are high?
Click to expand...
He asked what I use to raise pH in the rare circumstances I would need to. I rarely need to raise it. I was contemplating dumping VAST amounts of muriatic acid into the pool to combat the crazy high TA but that TA guide link literally says, "Do not attempt to lower your TA just to get the number down. Do so if you need to slow down your pH rising or have calcium scaling." We have no scaling but we DO have an ongoing battle with keeping pH down. Up until the very end of last year I used sodium bisulfate to lower it and had to put in 2-3 bags of the stuff over the course of a season in order to keep it down. I don't have a way to aerate the pool to bring pH back up, though, if I use MA to get it down. I don't have time to build anything. I'm open to purchasing a fountain or something, though. I need something that will make lots of tiny bubbles.
 
mgtfp said:
Aeration is the only way to raise pH without raising TA at the same time. Any chemical you add to raise pH will also raise TA, and will make the initial acid addition to lower TA together with pH pointless.

The purpose of aeration is to speed up CO2 outgassing which is what raises the pH. Like in soda water - when you let the bubbles bubble out, the water tastes less acidic.

If you can't aerate, then just wait, outgassing is happening on its own, just a little slower. Follow the process linked above once your algae is under control.



You have reached the endpoint of the titration when another drop doesn't change the colour further. If there is for example still a change to a more intense colour between 13 and 14 drops, but no further change with the 15th drop, then 14 is your drop count.



The complete chlorination cycle with liquid chlorine is pH neutral. Adding liquid chlorine initially raises pH, the following "use" of chlorine (i.e chlorine doing its job as a sanitiser/oxidiser and getting deactivated by UV light) is an acidic process and compensates the initial pH rise once the FC level is back to where it was before the liquid chlorine addition.

During normal pool maintenance, i.e smallish daily chlorine additions to maintain target FC, the pH fluctuations are so small that you will hardly notice them with standard pool kit testing. You will only really notice the overlaying pH drift from CO2 outgassing.

But when adding a larger amount to go from zero to slam for example, the effect is more pronounced. That's why the slam process asks you to reduce pH before adding chlorine.

Also keep in mind that from FC about 10ppm, chlorine interferes with the pH test, making it look like high pH even if it's not. Another reason for adjusting pH before a slam, because you're blind to pH during the slam.

For now, deal with your algae by starting to slam, then deal with your TA.
Click to expand...
Fantastic help there, friend. Thank you. Here's where are as of today. The algea is completely under control. See photo. FC this morning was a 9-9.5. pH read 7.5. Without the ability to aerate, though, the amount of MA I'll have to add will surely bottom out that pH with little ability to raise it. I need to either puchase or come up with something that will create lots of tiny bubbles.

My question on the chlorin test was not when to end the titration. It was when to stop adding the powder. I know there's a little blue scoop in the TF-100 kit but the notes on the card say that "getting the exact amount is less important." In the past I stopped using that little 0.5g spoon and just tipped some granualars into the test tube. For accuracy, though, as of the last 2 days I've just used the blue mini spoon to ensure I'm getting enough of the powder into the tube.

I did not reduce my pH before slamming (oops). At the time I didn't really care because it was the initial opening of the pool (5 days ago) and my focus was just shocking the Crud out the algea. I added 5 gallons of chlorine at 12:40am on 5/31. Historically that spikes the FC to around 15 (I didn't check it - didn't care. It was high and I knew it). By 9:41pm that night (21 hours later) it had dropped to 1ppm on the chlorine. I added 5 more gallons that night (on 5/31) and as of now (6/3 @ 11:34AM EST) it's down to 9.0 with no additions since Wednesday night. I also manually vacuumed out all of the dead algea (the robot cleaner can't run in 9ppm chlorine water).

So, now we're in "Swimming prep" mode. While the pH is in check the TA is not (and rarely ever is). If the TA is what's contributing to my ongoing battle with high pH (last year) than I'll take stock out in muriatic acid and get myself an aerator and start to wage the war.


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Jake&Clan said:
I can't understand how this pool filter is getting up in PSI so darn fast.
Click to expand...
None of us who have seen algae blooms in pools with DE filters will be surprised by this. As others have said, you need to follow the
SLAM Process and will need to babysit that filter until you have the upper hand on the algae.

Jake&Clan said:
Chlorine is too high to run the robot cleaner.
Click to expand...
Remember that robot manufacturers, like many pool professionals, ignore the FC/CYA relationship. There should be no problem with running a robot during a SLAM.
 
Jake&Clan said:
Without the ability to aerate, though, the amount of MA I'll have to add will surely bottom out that pH with little ability to raise it. I need to either puchase or come up with something that will create lots of tiny bubbles.
Click to expand...

At high TA and pH in the low 7s, pH will rise quickly on its own. If not, then there is actually not much need to force TA lower.

In the end, a pool has a certain demand for acid to maintain pH and TA (which usually ketos riding due to fill water). You have two choices: Either force down TA with an acid/aeration cycle and then have a lower acid demand for a while until TA creeps up again, depending on fill water TA. Or you just go with the flow and add acid when required. The total amount of acid used will be more or less the same, it's just when you add it.

Unless TA and CH are both high enough to create a scaling problem due to high CSI, I consider the active aeration as optional. Keeping pH in the low 7s should bring TA down quickly.

I can't find any CH results in your PoolMath.
 
MITBeta said:
None of us who have seen algae blooms in pools with DE filters will be surprised by this. As others have said, you need to follow the
SLAM Process and will need to babysit that filter until you have the upper hand on the algae.


Remember that robot manufacturers, like many pool professionals, ignore the FC/CYA relationship. There should be no problem with running a robot during a SLAM.
Click to expand...
FC got down to 6.0 and I let her rip. Good to know, though. I hadn't factored in the impact of CYA on the motor.
 
mgtfp said:
At high TA and pH in the low 7s, pH will rise quickly on its own. If not, then there is actually not much need to force TA lower.

In the end, a pool has a certain demand for acid to maintain pH and TA (which usually ketos riding due to fill water). You have two choices: Either force down TA with an acid/aeration cycle and then have a lower acid demand for a while until TA creeps up again, depending on fill water TA. Or you just go with the flow and add acid when required. The total amount of acid used will be more or less the same, it's just when you add it.

Unless TA and CH are both high enough to create a scaling problem due to high CSI, I consider the active aeration as optional. Keeping pH in the low 7s should bring TA down quickly.

I can't find any CH results in your PoolMath.
Click to expand...
No scaling just a constant ever ending need to lower my pH. As of "right now" pH is steady at 7.58 but as I add chlorine that undoubtedly changes.


You are all correct about the algea bloom and the DE battle. It took 3 back washes and a deep clean (but not a soak) of the fingers to get it under control but it appears the PSI is staying steady now. Between 10 gallons of total chlorine added, three backwashes, the deep clean, muriatic acid to stabilize the ph, a manual clean of the pool with a vacuum, 2 robot cleans, and hours of tending to it... I know have a crystal clean pool ☺. Kids swam yesterday (and it was 73 degrees. They're nuts).
 
Jake&Clan said:
My question on the chlorin test was not when to end the titration. It was when to stop adding the powder. I know there's a little blue scoop in the TF-100 kit but the notes on the card say that "getting the exact amount is less important." In the past I stopped using that little 0.5g spoon and just tipped some granualars into the test tube. For accuracy, though, as of the last 2 days I've just used the blue mini spoon to ensure I'm getting enough of the powder into the tube.
Click to expand...

(I had typed this earlier today, but just realised that I must not have clicked on "post reply")

You basically have to add enough powder to make the water turn pink. Any more will not have an impact on the end result. Usually one heaped spoon is enough. At very high FC levels a bit more might be required to counter bleaching out of the powder.

I'd recommend to use the little spoon. Not just to get the amount right, but also to be as quick as possible and minimise the amount the container is open and to avoid getting any water splashes into the container when just tipping some powder into the sample. The powder really doesn't like getting damp or even wet.
 
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mgtfp said:
At high TA and pH in the low 7s, pH will rise quickly on its own. If not, then there is actually not much need to force TA lower.

In the end, a pool has a certain demand for acid to maintain pH and TA (which usually ketos riding due to fill water). You have two choices: Either force down TA with an acid/aeration cycle and then have a lower acid demand for a while until TA creeps up again, depending on fill water TA. Or you just go with the flow and add acid when required. The total amount of acid used will be more or less the same, it's just when you add it.

Unless TA and CH are both high enough to create a scaling problem due to high CSI, I consider the active aeration as optional. Keeping pH in the low 7s should bring TA down quickly.

I can't find any CH results in your PoolMath.
Click to expand...
Sorry, light bulb. I didn't realize that calcium hardness and the scaling you're talking about were linked. I've never tested for calcium hardness but I will this afternoon
 
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