Total Alkalinity questionn

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reynolds357

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Jun 14, 2013
59
Atlanta, GA
I have read posts and learned from this forum for a couple of years. I finally joined today to answer a question I have that no one seems to be able to give me a logical answer to.
I have an above ground pool. I have maintained it for several years. I Use HtH 10% liquid Sodium Hypochlorite, HTH Calcium Hypochlorite granular shock, and in the extremely rare event I need to adjust PH up I do it with borax. Rarely I uses oxi shock to adjust Ph down. Cya is kept in the 15 range. PH almost always is 7.2 or 7.3. I literally use less than 2 pounds a year of borax to raise it. In the extremely rare instance I need to drop it I do it with oxi shock when the CC level is appropriate to use Oxi shock. Calcium hardness is 60. My total alkalinity does not even read it is so low. It has been off the charts for a couple years. When I first opened the pool I kept it in the recommended ranges and constantly fought with high ph and had to regularly use muratic acid. It was an endless, and I began to believe pointless, ritual of baking soda, acid, baking soda, acid. I quit trying to keep the alkalinity up. I thought, based on everything I had read, that I would constantly battle PH shifts, but that has not been the case. MY PH stays, for the most part, constant. If I am having absolutely no PH issues, and have not had any issues for over two years with T.A. off the scale, is there some other reason I should maintain it? The pool seems to be working perfectly with no measurable total alkalinity. I am quite sure that if I switched to an acidic chlorine that I would have a royal nightmare, but using two forms of basic chlorine, I have a very easy to maintain pool.
Any thoughts?
Thanks in advance.
Hal
 
How are you testing?

If your pH is that steady then you have to have to have some TA. If you had zero TA then your pH would be 4.6, so it has to be somewhere above that.

That being said, if the pH is stable and there are no problems with it, I'd leave it alone. Even if it's 50 ppm it's fine if the pH is stable.
 
I am testing three different ways. The first is somewhat unreliable would be test strips. The second test would be at the aqua chem pool store. They use an extensive chemical kit. The third testin method is at an Oacsis pool chemical dealer. He has the series of foil topped vials that contain test reagents that you add pool water to; then they are placed into an electronic reader. I have had the water tested three times at the Aqua Chem store and 6 or seven times at the Oacesis store in the last two years. Every time, the TA is low enough that it causes no color change in the Chemical the Aqua Chem store is using and it is lower than the digital testing system, used by the Oacesis dealer, can read. On a test strip, it causes a very, very slight color change, but is definitely in the "very low" range.
 
Been following for years and don't have a test kit? tisk-tisk Even the HTH 6 way test kit from walmart would be better than strips and pool stores. (I think I read that somewhere) I don't think your gonna get the kind of answer you want since you only have test strip and pool store numbers to go on.

How much chlorine do you lose with CYA at only 15?
 

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Scott, I have the reagent test for Free Chlorine, Combined Chlorine, and PH.
The pool stores test the rest for me free. The Bio-guard store uses the same chemicals in the Taylor and I watch them test it. I guess I will order the T.A. pack for the Taylor kit. I don't have any pool problems, just trying to solve a T.A. mystery.
 
I do not use a whole lot of chlorine. My FC level drops to about .3 - .5 by sundown if it is a hot and sunny day. In June, July, and August, I go through a Gallon of 10% every three days. That does not account for the amount of Chlorine I use for super chlorinating the pool. I pay $2.99 per gallon for HTH 10%. I use about $1 per day of chlorine for sanitizing and about $4 per week for superchlorination. I used to keep CYA in the 70 to 80 range. I have several commercial chicken houses close to my pool. Sometimes I get chicken feathers out of my skimmer. The chicken houses cause algae nightmares. When the CYA level was kept high, I did nothing but fight algae and water mold. I had to keep the chlorine so high to kill off algae, that many times I could only swim in the pool a couple days a week. My options were enough copper to stain the dickens out of everything or so much chlorine you could not swim half the time. I did some work to my pool and replaced about 2/3rds of the water. When I refilled it, I decided to try using only non-stabilized chlorine. For me, non-stabilized is the only way to go.
 
I had mild rising pH with TA offer 120, but once TA dropped down to 70 it became very stabler. Experiment, but start with three recommendations here.

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Hi,

I have sort of the opposite problem with my above ground pool. This is the 3rd year we've had this pool. The first two years, the CA, Ph and FC were all pretty easy to maintain. From the start, the TA has always been really high. I forget what it is, since I haven't measured it in so long, but I just remember it was well above recommended levels. Like the OP, I would try to lower it, then fight the Ph for weeks. Finally, I found somewhere in this forum, I believe, a thread concerning hard water. I live in San Antonio, TX, where the water is very hard. From what I remember, if the water is super hard, you'll never get the recommended TA level. So I just left it alone. After that, I just kept the Ph and FC where they needed to be, no problems. Until this spring. I guess I used too much Trichlor over the winter, or maybe cumulatively over the months leading up to winter closing. At any rate, my CYA has been off the chart since. I only get about 1/2 inch of water in the test vial and the black dot is gone. I have the TF-100 test kit, btw. In the spring, I replaced half the water and totally cleaned out the DE filter. After refilling, still the same issue with CA. I even purchased the bottle of 50CYA water from tftestkits to make sure I was reading the test correctly. As a result, I've been keeping the FC between 9 and 19 for the last several months. The Ph remains a solid 7.5 to 7.8. I've also switched from using Trichlor to using store bought bleach. So now, I'm looking at replacing half the water and cleaning the DE filter once more. I'm hoping this will finally clear up the CYA problem. I hope.

So, on to my actual question. If the TA is still off the chart, as I suspect it will be, can I just ignore it as long as the Ph and FC are inline?

Thanks,

Mike
 
Welcome to TFP! :wave:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. So the higher CYA levels should not be a surprise and to keep CYA in check you need to use a hypochlorite source of chlorine such as chlorinating liquid or bleach.

You can ignore your TA if you keep your pH and CH low enough to not have the Calcite Saturation Index (CSI) be too high. If it gets closer to +0.7, you can get calcium carbonate scaling in the pool. Even at +0.3 the water might look a little dull. However, with your higher TA level I suspect it may be difficult for you to keep the pH lower. So you may be needing to add significant amounts of acid.

Why don't you post a full set of water chemistry numbers and we can tell you more. You can also use PoolMath to calculate the CSI and see how closer you are to possibly getting scaling. I presume your above ground pool is vinyl, correct? If so, there's less risk of scaling at higher CSI though eventually even a vinyl pool can develop scale.
 
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