Calcium Chloride

Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
My husband is following the guidelines here, got the Pool Math app and switched us to liquid chlorine. He has a Taylor K2006 test kit. We opened and got chlorine in and had to boost the calcium hardness. We had a bag on Balance Pak 300 (calcium chloride from pool store) and put that in which got the CH up to 250, but also raised pH to 8.0. TA was 90 at the time, CYA 40, temp was 55 but has risen to 60.

We've had a good deal of rain - FC is 4, pH 7.7, but CH has dropped to 200 and TA to 65. Water is sparkling clear. I think the CH is most important so I looked on here for sources of calcium chloride and (long story short) was able to get some Prestone Driveway Heat at Lowes $10 for 9.5lb (got 3). That compares to 7lb Balance PAK 300 for $18. PoolMath says 20lb to raise CH to 275, after which we'll get some baking soda in for TA. Is it OK to sprinkle right in or should it be diluted in a bucket? He can brush after. Thank you in advance.
 

PoolGate

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TFP Guide
Jun 7, 2017
6,142
Damascus, MD
Pool Size
29000
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Plaster
Chlorine
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Jandy Aquapure 1400
I would not worry about calcium for now. Get everything else in balance and then see where you are with it. If you pre-mix it in a bucket it generates a LOT of heat BTW. Enough to burn you so do not mix with your hands! I also would not worry about adding baking soda until everything else is balanced. T/A of 65 is fine as well. Get your CYA to proper level. Add acid to lower pH to your level if needed. Then see where you stand and your CSI index.
 

Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
Great to have someone nearby responding, same cold wet spring, and a similar sized pool. The only level that indicates as out of recommended range is CH, and CSI is -0.43, so I conclude that everything else is in balance. Thanks for the bucket tip, he says he will sprinkle one 9.5lb container in all the way around then brush the whole pool and retest in the morning after the pump runs on high overnight. A few years ago I spent big bucks for resurfacing so I want to be careful about the plaster.
 

PoolGate

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Jun 7, 2017
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Damascus, MD
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Yep you're in the next county. Do you have the speed stir? The CH test benefits a lot from it. You'll get a different result.
 

Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
No speed stir but based on your comment he used the cap and shook the reagents and water in the tube. He put in half a jug of chlorine plus 9.5 lbs of the Driveway Heat - readings this morning are FC 5.0 pH 7.8 TA 70 CH 250 temp 58 CSI -0.21. He is going to add more Driveway Heat, maybe a whole other container, to get CH higher. We see that seems to raise pH so he's going to use some Lo N Slo from the pool store (he says Muriatic Acid is a bridge too far) to lower pH, but that also lowers TA. He'll put those two things in then consider adding baking soda.

Back to my original question - when he sprinkled in the Driveway Heat the pellets went right to the bottom, so he did it in three parts and brushed after each. That appeared to dissolve it. We did notice a white film in the skimmer this morning - can't say for sure what that is but what else but the Driveway Heat (calcium chloride) could it be. Maybe something from the other 8-10% of the ingredients.
 

PoolGate

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Jun 7, 2017
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Damascus, MD
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Jandy Aquapure 1400
Muriatic acid is what you should be using to reduce ph. Not sure what's in that other stuff.

For the calcium just run the filter on high until it is totally dissolved. Stir the water up when possible. Don't take your ch any higher you'll regret it later. Csi is perfect right now!
 

shoot_the_goalie

Well-known member
May 15, 2018
57
NY
Make sure if you're using CaCl that's meant for typical "road salt" use, that it's pure 100% CaCl, and doesn't have any additives or inert ingredients in it. Also, why is muriatic acid a "bridge too far"? If you're worried about the caustic properties and fumes of MA, you can always use a product like Acid Magic, which is low fume.
 

Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
Recommended chemicals here:
I looked up Peladow which is mentioned by name, and the MSDS has nearly the same ingredients as what we used. So I have to conclude that shoot_the-goalie entry is an opinion which I appreciate but when having to make a decision think it prudent to go with Pool School.

The feedback on muriatic acid is he won't use it for anything else, and doesn't want to store/handle it, followed by a comment about all the dangerous chemicals he's had to take to the landfill on days when they allow hazardous materials. His call.

PoolGate warning about CH level reminds me of CYA warnings, the reason why we switched to liquid chlorine. Too much reduces the effectiveness of chlorine and the only way to get it out is to remove water. But - my levels are at the bottom of PoolMath recommended and 100ppm below the low end of "ideal." So I'm still uneasy. But - pool store water tests (we have one from when we opened) recommends 200-275, Taylor (test kit folks) 200-400. So I'm going to go with PoolGate.
 

PoolGate

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Jun 7, 2017
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Damascus, MD
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With a new plaster surface, you are going to be going through a lot of acid to keep your pH down. Probably a gallon per week. The sodium bisulfite you are using (lo n slo) is not recommended by TFP due to its corrosiveness to metal surfaces. You can use it sparingly, but long term, muriatic is the best bet. Muriatic is a consumable so there will be no time when you need to get rid of it. During the season in fact, muriatic and chlorine are typically the only 2 chemicals you should be adding to your water.
 

mrbookmanlibrarycop

Well-known member
Aug 30, 2019
79
Westchester, NY
Pool Size
22000
Surface
Plaster
Chlorine
Liquid Chlorine
To answer your question about the calcium chloride, i usually premix in a 5-gal bucket (fill half with pool water) and stir with a paint stick until it is dissolved. It does generate some heat so I use gloves as well.

But I find that easier than broadcasting it at the deep end and brushing until its dissolved. You have to be quick because it can stick to the surface pretty easily.
 

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Winger 03

Well-known member
Sep 7, 2009
340
Frederick County, MD
To answer your question about the calcium chloride, i usually premix in a 5-gal bucket (fill half with pool water) and stir with a paint stick until it is dissolved. It does generate some heat so I use gloves as well.

But I find that easier than broadcasting it at the deep end and brushing until its dissolved. You have to be quick because it can stick to the surface pretty easily.
I do the same - but the water does get really hot.
 
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BassPlayingDude

Gold Supporter
Jun 13, 2018
439
Media, PA
Pool Size
9000
Surface
Plaster
Chlorine
Liquid Chlorine
Get some lab goggles and some gloves and use Muriatic Acid .. nobody loves it, but it's by far the best thing to use. I put a measuring cup on the ground right by my return, goggle and glove up, hold my breath, unscrew the cap, pour it into the cup, screw on the cap and dump it into the return stream. The whole process takes about 20 seconds tops. Just rinse the plastic measuring cup out in your water and you are done.

 
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Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
Good insight BassPlayingDude - your coping looks just like ours. We'll consider the calcium hardness and pH chemical issues addressed. Two other things have come up. The first relates to pH - it has been steady 7.7 since right my May 9 post. Husband is concerned about the amount of chlorine he is putting in (compounded by issue #2) and read in the Taylor materials that the lower on the 7.2-7.8 scale you are it will need to add less chlorine. He's going to try and keep it at 7.6, maybe 7.5. He's using Pool Essentials 10% and it in order to maintain desired levels is having to put more in as the water warms up (now up to 74 degrees). We get a good bit of sun - he got a tip from a buddy and connected a dark 150' garden hose to one of the returns then coiled it tight and flat on the pool deck before it empties into the pool.

The second issue is he went to the pool store and had the water tested, and was bummed to see that CYA had gone from 40 to 80, which matched his testing. Due to the complexity of using the Taylor kit he was hopeful he had misread it but no such luck. This elevates target FC to 9-11, while he was hopeful to be able to keep it in the 5-9 range. Considering it is only Memorial Day he is disappointed. CSI is -0.19.
 

BassPlayingDude

Gold Supporter
Jun 13, 2018
439
Media, PA
Pool Size
9000
Surface
Plaster
Chlorine
Liquid Chlorine
I don't think trying to "steer" it at that micro-level is going to work. I just let mine drift up to 8 and then knock it back down to 7.4 with acid once in a while. It's much better to just let your pool find its natural equilibrium, IMHO. 7.7 pH is absolutely fine. If your pool wants to stay there by itself, why fight it? As for the CYA level, you could just exchange some water to get it back down a bit, but natural splash-out and pump-out due to overfill from rainstorms, etc plus refill from evaporation will bring it down naturally over the course of the season. I like to keep mine a bit lower (50 ppm) so that if I go on vacation I can use tablets in a floater without having to worry about it, but running @CYA 80 with 9-11 FC is also fine. The amount of chlorine that you will have to add will remain about the same. People who have a SWCG run their CYA at that level all season long. The only disadvantage is if you have to SLAM you will have to use a LOT more chlorine to reach your SLAM target, so I'd be very vigilant about not letting it get below the recommended FC level ( 9-11ppm) for that CYA level.
 
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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,177
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
You should really reconsider using dry acid. Muriatic acid is not as dangerous as people (especially pool stores) make it out to be. Dry acid is more expensive to use and it adds sulfates to your pool water. You expressed concern about your “expense refinishing” of the plaster … well, sulfates are terrible for plaster surface. Look up the term “sulfate attack” and read about that. Unless you can guarantee that your fall/winter pool closure will result in significant fresh water exchanges each spring, the sulfates will build up over time and do damage. There are very easy and safe ways to handle and store muriatic acid, it just requires a little bit of effort and a realization that the people that like to sell you very expensive dry acid want you to be afraid of learning something new …
 

Mimi Pool

Member
May 8, 2021
13
Howard County, MD
Pool Size
28400
Surface
Plaster
Chlorine
Liquid Chlorine
JoyfulNoise, we had made the decision to use Muriatic acid when that need arises due to convincing recommendations herein.

We do get fairly extensive fresh water exchanges - we typically pump out three times per winter. We've exclusively used pucks in seasons past so the CYA would be in the 30s in spring but by closing around 120. This year just prior to opening (April 28) CYA was 30-40 (FC 0 pH 7.0 TA 40 CH 100). We opened May 3 and by May 6 my husband had (FC 5 pH 7.7 TA 65 CH 200), On May 29 he checked CYA and rounded up to 90 which didn't seem logical, so I got it tested at the pool store and they reported 85. He was really bummed - we've used only 10% liquid this year except for a long weekend away when we put pucks in the chlorinator and upon return it hadn't even used up one. Based on FC/CYA that meant we needed much higher FC levels than we anticipated so that is how we ended up looking at phosphates, in addition to it having been reported on the pool store test and catching our eye.

For those who would like to read more on the phosphate topic I refer you to a forum titled "Phosphates.....are they worth removing??" that is pretty lengthy, but really all you need to read is on p. 23. Very credible folks like JoyfulNoise, Swampwoman, and Leebo posted there - see post #457 by Leebo, the originator of the thread which I found very informative.
 
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