High ph, low alkalinity

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vortrex16

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In The Industry
Mar 1, 2012
7
First off I want to say I own a pool business so have multiple pools with this problem because I neglected then based on my uncles training. Decided that I wanted to really learn about the chemistry and be an expert to give my customers great service. I've been trying since december to get my pools balanced with only a bit of improvement. Alkalinities were around 10ppm and ph's were around 8+. Now I have them around 50ppm alk, and 8.0 ph. But with the amount of chemicals I added to all these pools, and the fact that its the beginning of march, it seems to me that the method of getting these chemicals in are effective, but by very little.

As the subject says I have a problem with ph, low alkalinity. I just got advice today from my pool warehouse I should use sulfuric acid to drop the ph because it doesn't effect alkalinity, is this true? If not what do you recommend. I've been trying to add bi-carb and myruatic acid together, 2 scoops of bicarb(de scoops) and 1 gallon acid, its helping but not a lot. Is there a more effective way to deal with this particular problem? Is sulfric acid the best way to go? So then if sulfuric acid only effects ph, if this is true, I can add bicarb to raise the alkalinity to 100ppm and drop the ph to 7.4 with sulfuric acid? Is this right? I really need to find the best way to do this! Please help.
 
Welcome to TFP! Don't use sulfuric acid. Any change in the pH will change the alkalinity.

How are these pools chlorinated? That can make a big difference in pH control. If you have SWCG pools with low CYA, you may really struggle with high pH because the SWCG has to generate so long to maintain any chlorine.
 
What test kit are you using?
How are you adding the chems and what sizes are the pools?
Also, where are you located?

With TA at 10 ppm it's highly unlikely that the pH would be 8+.

I'll go ahead and agree with JT too. Don't use sulfuric acid!
 
I use liquid chlorine, which I was told has a ph of 13. I use they taylor test kit. I live in venice, fl. If you think 10ppm alkalinity with high ph is impossible, your are wrong, I've see it with the taylor test kit with my own eyes. Not just one pool, but almost all of my pools. Pools are average residential size pools. I'm adding acid by walking quickly around the pool while I poor. Bicarb I'm dumping in one spot because I was told that it would affects alkalinity more that way then ph. I've done a lot of research from different online sources.
 
I didn't say it was impossible i said it was unlikely!
Which Taylor kit are you using?

The best way to add the acid is to pour it directly in front of a running return. It's easier and it mixes quickly.
Bicarb affects alkalinity and pH a definite amount per the amount you add, regardless of how you add it. It also should be poured in front of a running return.

If you haven't already, you should familiarize yourself with the Pool Calc.
 
I have used a pool calculator, but so far the numbers don't make sense based on my current methods. What id like to know is, if you had this problem how would you approach it, low alk, high ph. What chemicals are most useful for this situation. I definitely think adding CYA will help me, because that means I won't to have to add as much chlorine to the pool, which has a high ph. Help and responses are very appreciated.
 
Using liquid chlorine is basically a pH neutral event. It raises the pH when you add it but it lowers the pH as it's used up, so it works out to be close to a pH neutral event.

Having said that. I'd use baking soda and 20º Baume muriatic acid to adjust the pH and the TA. I'd add enough acid to get the pH to about 7 and then add enough baking soda to get to about 80 ppm TA. You're probably going to have to seesaw back and forth a few times to get the numbers you need.

Using bleach I'd shoot for a final TA of about 70 and a pH of 7.5 and see how stable that is.
 
No actually my FCs are in normal range. That's pretty much what I've been doing, seesawing for months to get ph and alk in range. Just seems to be a really slow process? Thought maybe my methods could be improved on..Using bicarb and Muriatic acid that is. what does baume mean btw
 

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Just seems to be a really slow process?
Click to expand...
YOu should be able to adust pH and TA into acceptable ranges in just an hour or so if you use the pool calculator and test and dose accurately. Something is not as it should be if you have been struggling with it.

1. Test TA

2. Adjust TA with Baking soda per the pool calculator.

3. Retest TA an hour later to confirm dosage had the desired effect. (or pretty close)

4. Test pH

5. Lower it with muriatic or raise it with Borax using the pool calculator

6. Retest pH an hour later to insure your dosage had the desired Affect.

7. Make an final adjustment on pH if necessary and then go back and retest TA

8. Make your final TA adjustment

Total time should be two hours or so......the key to it is testing accuratley and using the pool calculator to help you dose the pool correctly.
 
When I said "seesaw" a few times I was thinking 2 or 3 adjustments close together. It shouldn't take very long to get both TA and pH into range.

If you'll look near the bottom of the Pool Calc you'll see a field for effects of adding chems. This will give you an idea of how much adding a certain amount of each chem will affect the balance. That way you can tell how much you'll need to adjust to get it where you want it.

Which Taylor kit are you using and how old are the reagents?

While you're at it post a full set of test results.
FC
CC
pH
TA
CH
CYA
 
When the TA is really low, the PH can swing around wildly. One you get the TA level up to something more reasonable (at least 60) the PH will be quite a bit more stable.

As duraleigh said, it is very important to get your TA up to something reasonable first, and only then try to adjust your PH. Adjusting the PH will have some effect on the TA, but not an especially large effect. After you adjust TA and then PH, you will most likely need to adjust the TA again. In extreme situation a third cycle might be required, however by then (if not before) things should have stabilized and you won't see any more short term seesaw effect. There can still be a smaller longer term seesaw effect, with TA swings taking several weeks or even months, by that is fairly easy to keep under control with regular additions of baking soda.
 
Well I can't stay at a pool for 2 hours one a pool route, I have a lote of pools to do, and I don't have a weigh machine onsite to measure ounces, or lbs so I know the exact amount to add. If this was my personal pool that would be doable. I have more then one pool with this problem unfortunately. And I'm add a lot of chemicals, usually full gal of acid, and 2 1/2 de cups of bicarb or 3 cups if the alk is low.
 
Without getting it stabilized one good time you're always going to be fighting it. You really don't need to be able to weigh onsite, the Pool Calc gives you the amounts in volume if you hover over the quantity to add.

Good luck with getting them straightened out.
 
Definitely presents challenges, but has been perfected by pool service companies, I unfortunately was not trained properly, and can assure you will perfect it as well. For the most part, from what I've seen in the field, pools maintained by professional look and test better then home owners, not because they are incompable, but because they don't spend the right time necessary to learn about pool chemistry, nor do they seem to want to maintain the cleanliness of their pool. That's my observation

Now to the reason I'm posting, I have 3 extremely credible sources that tell me sulfuric acid doesn't not affect alkalinity at all. I will try this and repost if it works or not. I feel this is really important knowledge if true, to not only fix my current issues but others as well, again I want to thank the mods and others for posting on this topic, I really appreciate it.
 
vortrex16 said:
Well I can't stay at a pool for 2 hours one a pool route, I have a lots of pools to do, and I don't have a weigh machine onsite to measure ounces, or lbs so I know the exact amount to add. If this was my personal pool that would be doable. I have more then one pool with this problem unfortunately. And I'm add a lot of chemicals, usually full gal of acid, and 2 1/2 de cups of bicarb or 3 cups if the alk is low.
Click to expand...
Decided that I wanted to really learn about the chemistry and be an expert to give my customers great service.
Click to expand...
I unfortunately was not trained properly,
Click to expand...

Hi vortrex16 and Welcome to TFP! :-D
If this is Your business, your the one that's in charge. I'm a engine builder and build billet engines from a solid block of billet aluminum. Tools and CNC machines HAVE to be bought or I couldn't do the job or even get it close. I would think you need the proper tools to do what your trying to do successfully.
The science taught here works, math is your best friend.
Your customers pool water is no different than our water when we started. All of us have had problems, and all very different problems.
I would have to say that this is NOT a COMMERCIAL pool site, so our info for you servicing residential pools is mainly what is addressed here.

IMO, you should heed the advice given here from these mods, (actually even the owners of this site) they have seen a lot and have experience.

This is the BEST college education you could ever get for FREE! Think what tuition costs are these days!
Laptops are cheap nowadays, there's no reason for you... to not to invest in tools for your trade and have one in your service truck for you to use the online pool calculator that WILL help to fix these issues your having with your customers pools, keep in mind this is WHY your to be paid, to do a job and do it well. :goodjob:
I'm NOT in the business, but have paid a lot of attention around here and this is my take on it.
Chuck
 
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