Added too much soda ash, now water cloudy

[bzerk86]

Hello All,

I adjusted my pH up today as it was a little low at 6.9. I used poolcalculator.com, entered all my values and it advised to add 2430g (5.3 Pound) by weight of washing soda or soda ash. The pH usually drifts up by itself and it did however a lot of rain lately drove it back down.
I purchased a 2.5kg (5.5 Pounds) bag of soda ash and added it in three batches after mixing in a bucket.

The first problem I encountered was very high pH, well over 8.2. I left it circulate for several hours however the pH was still off the chart. Out of curiosity I used another calculator, Pool Boy on my phone. It advised me to only add 1.7kg of soda ash for a .5 pH increase.

The second problem I still have is cloudy pool water. It's very foggy, however I can still see the main drain. I thought this might have been due to high PH so I started to add acid. First off using poolcalculator it advised to add 840ml (28.4oz) of 34.6% acid to lower the PH from 8.2 to 7.5.

With the acid added, the pH started to lower and then stopped at about 7.8. I used pool boy on my phone and it advised that 2.1L (71oz) should have been added. I continued to add the remaining amount of acid. The pool is now at a good 7.4 however the water is still cloudy.

My current levels are:

FC - 7
pH - 7.4
TA - 100
CH - 440
CYA - 90
TDS - 2800 - Most likely due to salt from liquid chlorine.

Problems I have are:
Pool is still cloudy, should I add some Alumina Salts? EG clear tabs for sand filters.
Why did poolcalculator give what appears to be incorrect measurements? I made sure my pool volume was correct and double checked my targets.

A bit of background if required.
My testing results are from a couple of different sources. Not the best I know however it seems difficult if not impossible to get a Taylor test kit in Australia. I use a Rainbow lifeguard 4-in-1 test for fortnightly checks as well as a AquaCheck TruTest digital strip reader for quick checks during the week, before and after swimming ect.

For other things such as TDS and CH, my local pool store checks for these things a few times a year. They are a family run business and after educating myself here, they don't oversell and give advise that closely matches that of TFP.

Further background on this pool: I moved in just over two years ago and the previous owners used Trichlor pucks in combination with CalHypo even though the system had a liquid acid and chlorine controller?!??. This of course lead to CYA of over 150, very high CH and hard to manage water. I did a half drain shortly after moving in and put the pool back on liquid chlorine ($20 per 15L in AUS). Since this things have been quite good!

Cheers guys!

Brian

 

[Patrick_B]

I just want to weigh in on the TDS mostly.

TDS alone is irrelevant. Every dissolved mineral in your water adds to that number, not just the salt in the Liquid Chlorine. Salts are a huge contributor to TDS, but there are likely other Chlorides in your fill water. A level of 2800 seems pretty spot on looking at the rest of your numbers and should not be of concern. Your CYA and CH are a little high and it is those numbers you should focus on, CYA first. If it were mine, I would reduce it with some drain and re-fill with a target of 40-50. The TDS will wind up where it does and there is nothing you can really do about it. It is representative of all components and will likely come down with a reduction of the others. Not much most likely, but how much will be determined by the TDS in your fill water, and how much water you replace.

Watch your FC number as you are sitting on minimum with a CYA 90 and 7 PPM FC.

 

[duraleigh]

The discrepancy in your results and your dosages did not come from the pool calculator. The pool calculator has proven accurate with probably more than 100,000 users on a frequent basis.

At some point, you will have to decide to trust the pool store or TFP.

TFP teaches a pretty narrow path of simplicity and almost no pool store additives. Even though the advice seems similar to you, trying to blend the suggestions from both resources frequently results in failure.

 

[bzerk86]

The discrepancy in your results and your dosages did not come from the pool calculator. The pool calculator has proven accurate with probably more than 100,000 users on a frequent basis.

At some point, you will have to decide to trust the pool store or TFP.

TFP teaches a pretty narrow path of simplicity and almost no pool store additives. Even though the advice seems similar to you, trying to blend the suggestions from both resources frequently results in failure.

I never trust someone who says "trust me" :-D

The tests were not the pool stores, pH, TA, CYA and Chlorine are all mine. Just seemed to be a pretty big difference both times while trying to increase my pH and then undo the damage caused.

Let me ask here, how much soda ash would you add to a 70,000L (18,500Gal) pool to increase the pH by 0.6? Then how much acid would you add to lower the pH by 0.6?

Perhaps I should post a screen shot of my calculations using poolcalculator.com for viewing and checking?

 

[bzerk86]

I forgot to mention that the cloudiness has started to clear. I added a clear tab (Alumina Salts made by Hy-Chlor Aus) and within the last hour there is a marked difference.

All I know is I never want to have to bump up my Ph again!

Thanks for the responses Guys!

I have been contemplating doing another half drain and fill, as per Brushpup's post. However its just too costly with utility prices in South Australia. Last time it added almost $350 dollars to the water bill. I have seen a slow decrease with CH and CYA with backwashing and no longer using products that contain these items. For that knowledge I thank Trouble Free Pool!

 

[duraleigh]

The pool calculator I am sure would give me the same results you got.

How do you know you needed to move pH by .6?

Test strips and a rainbow lifegaurd tester are not results I would put any faith in......trust me.

 

[bzerk86]

As per my signature I have a digital ORP and pH controller/peristaltic pump with live readouts of the chemistry. It has been calibrated with sample bottles from the manufacturer within the last few months. It showed a pH of 6.8 at its lowest and 6.9 at the highest.

Trust me if I could get a Taylor kit shipped to Australia, I would. It is clearly a superior, cheaper option than what I am using now. I've just got to the best that I can with what I've got.

So what dose would you give?

 

[bzerk86]

poolcalculator.com

Am I missing something. The result of adding this much did not give me the desired result of 7.5 it shot right up to 8.2-8.3.

Similar to lowering, the calculated amount was not even half what was required. At the risk of people pointing out something I have overlooked or not noticed, here are some screenshots.

 

[JamesW]

How did your pH get so low?

Is the acid pump working correctly?

Based on the available information, your pH should not be going down that low. When using liquid chlorine, the pH should tend to stay the same or rise slightly. Unless you have added something acidic, then I would suspect that the pH reading is incorrect or the acid feeder is malfunctioning.

 

[Patrick_B]

As per my signature I have a digital ORP and pH controller/peristaltic pump with live readouts of the chemistry. It has been calibrated with sample bottles from the manufacturer within the last few months.

A few months calibration is HARDLY something I would rely on as accurate "chemistry" readouts. I have worked with the best and worst pH sensors the market has to offer for the last 15 years. It is a large part of what I do for a living. The very best of the best cannot be relied on for three weeks without calibration, much less three months. Most ORP sensors don't last three days with much accuracy if they have it to begin with. Perhaps they perform better in pools, but I wouldn't count on it without extensive backup testing to prove it.

Why does the Pool Calculator have to be wrong? It's never been wrong once that I can remember. If anything, your volume, measurement, or some other parameter was off. If there were problems with it, it would have been known long before now. Thousands of people use it every day with great success.

 

[JamesW]

Also, you're showing a TA of 100 before adding soda ash, after adding soda ash and after adding muriatic acid. The TA would change each time a chemical was added.

 

[bzerk86]

To answer all the questions in an attempt to get an answer myself.

The pH drifted low due to rain (the only thing that has been added apart from chorine), it started to come up over a two week period with the addition of chlorine. The water temperature is quite cold at the moment 11c (52F) so there has been very little chlorine required.

Any gains in my pH were lost due to more rain. I attempted to aerate the water for a day with the spa jets and had very little effect on the pH.

It's unfortunate that I cannot be the owner of a Taylor test kit, that being said, every test method I have available showed a pH of 6.8-6.9. After the addition of soda ash, everything showed a pH of 8.1-8.2. I HARDLY think a discrepancy of .1 between several methods is any reason for concern. If anything the same issue would have happened if I did have the TF test kit.

To reinstate my questions about the poolcalculator.com

1: In the supplied picture, can anyone see something I missed? Is this how much you would personally add?
2: The doses for adjusting my pH twice, seemed incorrect by about double. Too Much soda ash to increase and overshot my goal. Not enough acid to lower and missed my mark.

An answer on why the pool calculator did what it did would be appreciated. I think I have provided enough information and been very forthcoming in any additional information.

 

[duraleigh]

An answer on why the pool calculator did what it did would be appreciated.

It did what it did because that's what it always does. Being repetitive, poolcalculator is used by thousands and thousands of pool owners daily and they get the expected results. Because you know all the other variables in your calcs to be correct, You are insisting on an explanation that cannot be provided

Being blunt, you have decided that the poolcalculator is wrong and you are right as if it has singled you out to provide you with false data. There's simply no logic in your premise.

I play quite a bit of doubles tennis in a group where everyone's skill level is well established. Even when I draw a partner that is one of the top 2-3 players, we still lose. The inescapable conclusion for me is that those guys must not be playing hard when I am their teammate.......it certainly couldn't be me.

I doubt you will believe this either, but moderate rainfall (2 or so inches) typically has almost no effect on pH. Chlorine is pH neutral in pools and reasonably soon after addition, has no measurable effect.

 

[Dmsattelberg]

Do you happen to have the bag of the soda you put in.....take a picture of the ingredient list....

 

[danacc]

A few thoughts:

• It may be expensive, but it is certainly not impossible to get Taylor chemicals and tests in Australia. Start here: shipping-tf-100-test-kit-to-australia-t52581.html#p432954[/*:m:28cyyczp]
• How much chemical to add to change the pH of your specific pool water depends on several factors, and not all of them are asked by the pool calculator. If you want to know a precise amount, you need to do an acid demand test or a base demand test on your water.[/*:m:28cyyczp]
• The pool calculator result is only as good as the input you give it. It is very odd that your TA stayed steady at 100 while you added chemicals to change the pH. What you indicated in the screenshots is that it did. How much chemical to add to change pH in either direction is significantly swayed by the TA of the water. Seeing it tested as staying steady throughout this process sends up red flags.[/*:m:28cyyczp]
• Testing chemicals and methods that you used are known to have inaccuracies, and of course these will also cause error in what pool calculator tells you.[/*:m:28cyyczp]
• On top of that, the pool calculator itself warns you that it is not accurate for the pH swings you are asking it to calculate. In the pH box it says "Note: pH calculations depend on TA and Borate. Results are approximate and can be off significantly for large pH changes. Changing your pH will also change your TA." And at the very bottom of the web page it says "Note: pH calculations are not exact. These numbers are only suggestive of the relative magnitude of the pH change you can expect. Small changes, +-0.4, with pH between 7.2-7.8, TA around 80-120, and Borate near zero will be approximately correct. The further you go from those ranges the less these pH changes will correspond to reality." Your water tested outside of this range, and you were asking it for larger changes all at once than what it is telling you it can support.[/*:m:28cyyczp]

My advice would be to ask the calculators for smaller pH steps and do it in stages. Otherwise, you're playing in increased error rate zones unless you do an acid demand or base demand test on the water. Also, your TA results are suspect. How did you get them?

 

[JamesW]

To reinstate my questions about the poolcalculator.com

1: In the supplied picture, can anyone see something I missed? Is this how much you would personally add?
2: The doses for adjusting my pH twice, seemed incorrect by about double. Too Much soda ash to increase and overshot my goal. Not enough acid to lower and missed my mark.

An answer on why the pool calculator did what it did would be appreciated. I think I have provided enough information and been very forthcoming in any additional information.

In my opinion, I think that the input pH of 6.9 was incorrect. I don't think that rain is going to lower pH that much when the TA is 100 ppm. I would be interested in the pH of your local rain, as it would have to be very acidic to drop the pH that much. What was the pool pH before the rain?

When raising pH, I would always use half of the recommended dose and recheck to avoid overshooting. Also, aeration can raise pH quite a bit when the TA is too high.