How does Borate affect TA?

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hmiser

hmiser

0
Mar 11, 2013
15
Walnut Creek, CA
Love this site.

Just getting started with BBB. Got my TF-100. Specifically purchased from NC despite living in CA because I wanted to contribute.

Started with a green swamp. Drained 75% of water to reduce my 100+ppm CYA. Refilled, brushed, changed cellulose fiber on my Pentair DE three times. Finally procured the necessary Borax to run borate.

My question: TA is low at 40ppm. Added enough borate to get me to 50ppm per Pool Calculator - love this too! My Ph is 7.2 my TA is 40. I didn't add anything to adjust either since I'm just adding the Borax and understand it increases Ph. But how does it affect the TA? Should I go ahead and raise the TA partially at this time? Should I add Muriatic Acid to counter the Borax at this time? Partially?

I also added Calcium to get to 250ppm per Pool Calculator.

Here are my starting values before adding the above.

FC - 8ppm - added enough bleach to get to 16ppm
CC - <1ppm
pH - 7.2
TA - 40ppm - did nothing yet since I added Borax
CH - 40ppm - added enough Ca to get to 250ppm
CYA - 27ppm - I've got some legacy tablets floating around to get me to ~30ppm
Borates - 0ppm - I added enough Borax to get me to 50ppm
 
Aha, I think I'm excited to post in a forum. I don't do that ever.

I'm just realizing that the Pool Calculator tells me what happens when I add any chemical. Not just Chlorine. Amazing.

Looks like the Borax will add 115ppm TA and 6.4pH which puts me at 155ppm and 13.6pH respectively. So I can use the Pool Calculator to get the appropriate amount of Muriatic Acid to add. Lower than recommended assuming I was TA and pH balanced. Then I'm gonna need to add some Soda Ash to get the pH up a bit. I'll do this and repost test results.

Thanks again,
-hmiser
 
Ok right. Baking Soda raises TA. Thank you.

I added Borax to get me to 50ppm Borate. But since I was low on TA(40ppm) and pH(7.2) I knew I shouldn't add a comparable amount of Muriatic Acid to counter the affects of the Borax.

So, I'm planning on adding 2.5Gallons of 34% MA followed by 135oz of Baking Soda, followed by 20oz of Soda Ash - per pool calc. If I didn't mess up the math this should get me to 7.46pH and 113 TA by tomorrow morning - filter running all night. Then I can go from there since I'm estimating on my pool size - it's odd shaped.

I'll post my numbers tomorrow. I think I'm on the right track -yes?

Thanks again,
hmiser
 
NO. When you add 20 Mule Team Borax, you only need to then add Muriatic Acid. Then, and only then, after measuring where you are at should you consider adjusting the TA (or alternately, you could adjust your TA first with baking soda before you add the borates using Borax and acid). You don't want to make too many modifications at once. Also, you normally don't add all the borax or acid in one shot since it swings the pH too much. Did you read Adding Borates -- Why and How?

So since you added the Borax already, add the acid now and get your pH in line. Then, and only then, after your pH is within a reasonable range (roughly 7.2 to 7.8) you can add baking soda to raise the TA. You should not need to use soda ash at all since that raises the pH and at this point you are trying to lower your pH with acid. Also, you do NOT want your TA target to be so high -- usually it's not more than around 80 ppm. See Recommended Levels.
 
I think I'm on the right track -yes?
Click to expand...
No, not yet. You would help yourself by not adding one more item to your pool until you post a complete set of CURRENT test results (today) and then wait for the suggestions of someone on this forum.

You are getting ahead of yourself. Reread or read "The ABC's of Pool Water Chemistry" up in Pool School. It tells you how to adjust your chemistry but don't do anything until you post back CURRENT results.
 
duraleigh said:
I think I'm on the right track -yes?
Click to expand...
No, not yet. You would help yourself by not adding one more item to your pool until you post a complete set of CURRENT test results (today) and then wait for the suggestions of someone on this forum.

You are getting ahead of yourself. Reread or read "The ABC's of Pool Water Chemistry" up in Pool School. It tells you how to adjust your chemistry but don't do anything until you post back CURRENT results.
Click to expand...


Thank you for all the great advice and support.

Sorry. I do get ahead of myself and I'm bad I helping myself. And I got excited and just through everything in at once and then scrubbed the pool for 3 hours last night to midnight. The pool light was particularly helpful and motivating as it really shows the dead algae clouds when you brush. I have a nice burn in my shoulders this morning.

Ok since I added everything before I read the replies (again sorry about this) I'll tell you what I did. Using the Pool Calculator and my starting values I added:

- 352oz of Calcium to get me from 40ppm to 240ppm, today's reading 180 (more on this later)
- 706oz of Borax to get me from 0ppm to 50ppm, today's reading was more than 30ppm but not quite 50ppm
- 320oz of Muriatic Acid to partially counter the Borax in view of where I was with TA(40ppm) and pH(7.2)
- 135oz of Baking Soda
- 20oz of Soda Ash

I made these calculations using the Pool Calculator estimating 12k gallons. My pool is oddly shaped and I've estimated as high as 15k gallons but I wanted to keep my initial chemical additions on the low side since I was adding everything at once.

Based on my starting and current levels of CH, if I back calculate, I think I can estimate that my pool size is closer to 17k gallons. Assuming all the Calcium is disolved(appears this way visually) and thoroughly mixed. If this is true, that I've a 17k gallon pool. That would address the lower current values compared to what I predicted of borate and TA. And why I haven't reached my FC target. Any comments or thoughts?

To recap I've included my starting and current values below. I'm planning on adding chlorine, changing the filter media, more reps of scrubbing, and sitting tight. Then I'll test again tomorrow morning. Thanks again for all the support and advice.

Starting This Morning
FC 7.5 11.5
CC 1 0
pH 7.2 7.8
TA 40 100
CH 40 180
CYA 27 didn't retest
Borates 0 >30,<50
 
hmiser said:
Based on my starting and current levels of CH, if I back calculate, I think I can estimate that my pool size is closer to 17k gallons. Assuming all the Calcium is disolved(appears this way visually) and thoroughly mixed. If this is true, that I've a 17k gallon pool. That would address the lower current values compared to what I predicted of borate and TA. And why I haven't reached my FC target. Any comments or thoughts?
Click to expand...

Yes - don't sweat it yet. Keep making minor adjustments in PoolCalculator until you see results that match expectations. The truth is your pool volume can be off by +/- 20% and it isn't likely to make enough of a difference in thngs to mess you up too much. Make an adjustment that is partway between what you initially estimated and what you now estimate and live with that for a few adjustments. The key is to incrementally approach these adjustments so you can learn what works without too many variables being adjusted at once.

hmiser said:
To recap I've included my starting and current values below. I'm planning on adding chlorine, changing the filter media, more reps of scrubbing, and sitting tight. Then I'll test again tomorrow morning. Thanks again for all the support and advice.

Starting This Morning
FC 7.5 11.5
CC 1 0
pH 7.2 7.8
TA 40 100
CH 40 180
CYA 27 didn't retest
Borates 0 >30,<50
Click to expand...

Hopefully you didn't add too much chlorine; 12 is the shock value for a 30 CYA.
 
Ok so I'm in the process of cleaning the finger elements of my Pentair FNS 60 and I might be having some problems.

The last time I did this a week ago(pressure increase from all the dead algae has been happening quickly and I don't have a multi valve for back washing) I noticed that the cellulose filter fiber I used (switched from DE because I'm in California and it seems easier). I noticed the filter media didn't appear to be evenly spread over the filter fingers. The top half of the fingers were heavily coated the bottom half was considerably less coated if even coated at all.

So I soaked them in real TSP overnight in a 44 gallon garbage can. I used 72 oz of TSP in about 40 gallons of water. I hosed them down again with my hose which is very high pressure. I paid particular attention to how I did this. I really worked the hose on the bottom of the fingers because this is predominantly where there seems to be a lack of filter media. I presumed it is because the were dirty/blocked by oils and what not.

I didn't acid wash at this time because I was anxious to get the filter back running.

So now I've taken the filter fingers out again and noticed maybe some better coverage of the media but not what I was hoping. Most of the media was concentrated in the top half of the fingers.

I'm assuming that the bottom, if truly clean should have the majority of filter media if not evenly spread. The water enters from the bottom of the filter chamber and the filter media has some weight. But I also think that if the top half of the filter was cleaner. Let more water pass through the filter fingers, then that's where the water would go and it would bring the filter media with it.

So maybe it's time for an acid bath?

So I rinsed the filter with my hose. Then I added 72 oz TSP to about 20 gallons in the same 44 gallon bucket. Thinking that this would double the concentration I used last time. Since the fingers stand straight up only the bottom half of the fingers(trouble area) would be exposed to the TSP bath. Maybe clean it better.

The following day I removed a finger, hosed it off and tried to check it. I filled it with water and it drained better than before. I then decided to test it by placing it in a 10 to 1, 34.5 Muriatic Acid bath. This time in a 5 gallon bucket with the bottom of the finger immersed. I did not seeing any fizzing or receivable reaction.

I then let it sit overnight.

Then next morning I tried to see what if anything happened. I filled it with water and it looked about the same maybe a little better.

I then thought to immerse the now clean finger in the pool water. Lifting it our horizontally to see if I could perceive any noticeable difference in flow - horizontally. This is not so easy to determine. It looked ok I guess. No noticeable blockage at the bottom compared to the top.

But it's really hard to know how helpful this "test" is since it's likely a different scenario once the fingers are in the stack and at pressure.

My question is, am I assuming that the filter media should be reasonable spread over the whole finger, top to bottom?

If so, and it's not spread evenly after TSP soak and an acid bath. What next?

Thanks again for all the great help. Once I get my filter back running I'll cycle the pool and retest and report.

-hmiser
 
Don't worry so much about the distribution of media. The process of opening the filter tends to dislodge media from some locations more than others. The thing to watch is the clean filter pressure. When the just cleaned filter pressure goes up it is time to do an overnight detergent soak.

You don't want to use acid unless you really need to, which is normally indicated by the fabric getting stiff and "brittle", kind of cracking when you flex it from calcium build up. From what you said, there is no sign of that happening here, so I would avoid acid.
 

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I'm curious about the CSI.

It's cold here in Northern California or at least it hasn't warmed up yet.

My pool is 50oF. It appears from using the Pool Calculator that temperature greatly affects the CSI. Or that CSI decreases with decreasing temperature. This seems counter intuitive to me as I generally see increased temperature increasing reaction rate and even solubility of solids. I have a plaster pool and I'm understanding the concern regarding a CSI below -.06 is that calcium will be pulled out of the pool surface.

Can someone offer me further explanation of this effect. Specifically the lower temperature increasing the chance of pool surface degradation?

My pool will likely average 70oF during the upcoming months. For now(at current temp of 50oF) I can compensate by running a slightly higher pH, TA, and CH. Keeping the CH as low as I can 300ppm or so. That way when my pool reached 70oF I can readjust my TA lower and get my pH closer to 7.5.

I'm installing a SWG next week and looking at the "Recommended levels for Plaster", TA is 60-80ppm. And adding salt at 3000ppm also decrease CSI.

Thanks again,
-hmiser

Lastly, I'm knew to forums. Should I repost this somewhere else as a new topic?
 
It has to do with the solubility of carbonates in water...unlike most solutes, they are more soluble in cold water than warm. Hence, fizzier warm soda than cold. Trying to keep the CSI right at a certain value is a real pain, and not worth the trouble. Yes, -0.6 will start pulling calcium out, but the real damage happens when people use tablets, never check anything, and end up with TA at 0 and pH at 3 or so. Keeping it within a range is good enough, and as long as you're paying at least a little bit of attention, nothing bad will happen.
 
Ok I think I understand. Thanks.

I found the following information from the U of Arkansas.

"Temperature

Counter to the typical increase of mineral solubility with increasing temperature observed for most minerals, many carbonate minerals are more soluble in cold water. For example, the Ksp for calcite at 0 and at 50 is 10-8.02 and 10-8.63, respectively (Garrels and Christ, 1965). These values represent about a four-fold difference in calcite solubility caused by temperature alone. A thorough discussion of the thermodynamic reactions of carbonate minerals solubilities is beyond the scope of this article. A simplified explanation for carbonate minerals being more soluble in cold water is that the dissolution reaction for carbonate minerals is exothermic, which results in higher temperatures favoring the solid phase over dissolved ions. A more detailed discussion for this unusual behavior can be found in Langmuir (1997).

In addition to an increase in solubility products with decreasing temperature, carbon dioxide is more soluble at lower temperatures, further favoring carbonate mineral dissolution in cooler environments. More carbonic acid is present in cold water at a given partial pressure of carbon dioxide (P) and carbonic acid concentration is the controlling factor for the solubility of carbonate minerals under natural conditions. Carbon dioxide is obtained from the air or from decomposition of organic matter that releases carbon dioxide which reacts with water to form carbonic acid. These factors combine to form the calcite compensation depth (about 4,500 m) below which calcite dissolves." from http://comp.uark.edu/~ksteele/gochemfiles/SteeleCarbonatePC-762.htm
 
I moved this topic over to "The Deep End" as it has become more appropriate for this forum.

"Just Getting Started" really needs to stay with very basic stuff so newbies aren't overwhelmed.
 
hmiser said:
This seems counter intuitive to me as I generally see increased temperature increasing reaction rate and even solubility of solids. I have a plaster pool and I'm understanding the concern regarding a CSI below -.06 is that calcium will be pulled out of the pool surface.
:
Can someone offer me further explanation of this effect. Specifically the lower temperature increasing the chance of pool surface degradation?
Click to expand...
I think you mean below a CSI of -0.6, don't you? -0.06 is close to 0 and not an issue at all.

As was noted by others, the CSI is not about reaction rates but is about what is possible -- thermodynamics. Colder temperatures do have slower reaction rates so a -0.6 CSI at hotter temperatures will have a more rapid dissolving of calcium carbonate than at colder temperatures. This means that the practical risk of a too low CSI is lower at colder temperatures.
 
Thanks Richard. I did mean -0.6.

Also, I'm very impressed with your breakdown of pool chemistry. No matter where on the web I look the references always seem to come back to TFP, specifically referring to your explanations. It's been fun geeking out on pool chem.

So thanks again to you and TFP for all the help.

My pool is clear and the numbers are within range. I'm waiting on an Intelliflo XF and a Circupool RJ 30 to arrive. I'm sure I'll be posting some more questions.
 
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