Couple post SLAM questions/concerns

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Azmp1

Azmp1

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LifeTime Supporter
Jul 20, 2012
311
Maryland
I successfully completed the SLAM process few days ago, couldn't be happier with the results. In the mean time as I'm waiting for CF levels to drop (still at 22.5ppm today and keeping the pool continuously open as we're finally getting sunlight today!), I decided to deal with my TA levels as I need to get them down to 80ppm range from ~140ppm (since I've converted to salt right before I started with the SLAM).
So, I added 2 gallons of MA over the past 48 hours and as of today my TA is right around 100. I'm holding off on adding more for now as my pH is already at sub 7 levels, likely low to mid sixes. I've had the pool open and been aerating as much as I can, but still I think my pH is pretty **** low and I'm hesitating to start adding Borax until I can do a definitive test on the pH level.
Any suggestions for the best approach at TA and pH in this situation? And is there any tricks on getting the chlorine to come down quicker other then sunlight?

Also, wife and the kids are on my case about using the pool today and im a bit hesitating on letting them swim with pH being that low... I know FC being at over 20 is ok and my CC is at zero, but im worried about pH... Is it safe?

And finally, I had my heat pump bypassed during the entire SLAM process as really didn't want to subject to these high levels of chlorine if I didn't have to, but now as the FC levels are slowly going down, am I OK to get the water flowing back through the heater again? What are the chlorine levels considered not safe for the heater? (I have new heat pump with titanium heat exchanger).

Thanks as always folks!
 
The low pH is more dangerous to the heat exchanger than the chlorine. Likewise to any swimmers. You shouldn't have added so much acid at one time. Our method is to lower pH to 7.2 and aerate back up, then lower it to 7.2 again over and over until the TA is where you want it. Same amount of acid is used, but the pool pH never gets down into the danger zone that way and remains swimmable the whole time. As it sits now, your pH is at best questionable since high FC tends to make pH read falsely high. Your pH may be much lower than you think.

Also, you should have had water circulating through the heat exchanger during the SLAM, so that an algae spores in the plumbing would get killed. Now it's too risky with that acidic water.

I wouldn't let anyone in the water until FC has dropped enough to get a valid pH reading. Which means FC less than 10. In the meantime, aerate as much as possible. If pH is still below the lowest pH reading after FC is down, add Borax a box at a time an hour apart until you see a color shift on the pH test. Then plug your numbers into poolmath and add more precisely what you need.
 
My pH was already low before I started the SLAM. 7-7.2. I'm not testing pH as I know the test will not be reliable, it's just me thinking since my pH was already low, by adding 2 gallons of Muriatic acid, it's probably much lower at this point. I only added one box of borax btw.
I was hoping that aerating will be enough to counteract the acid, but I'm not sure how much aerating is being done as I have that cheap sprinkler gadget that gets screwed into a return. I wish I could use my sheer descent, but it's outta commission at this point.

I'll stop with everything until can get the chlorine levels down.
Any tricks there other then sunlight?

Oh and yes, I did read the TA down pool school article, but the problem is that I can't test, so can't really follow that article. So it was me basically just tying to wing it in the mean time...

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Azmp1 said:
My pH was already low before I started the SLAM. 7-7.2. I'm not testing pH as I know the test will not be reliable, it's just me thinking since my pH was already low, by adding 2 gallons of Muriatic acid, it's probably much lower at this point. I only added one box of borax btw.
I was hoping that aerating will be enough to counteract the acid, but I'm not sure how much aerating is being done as I have that cheap sprinkler gadget that gets screwed into a return. I wish I could use my sheer descent, but it's outta commission at this point.

I'll stop with everything until can get the chlorine levels down.
Any tricks there other then sunlight?

Oh and yes, I did read the TA down pool school article, but the problem is that I can't test, so can't really follow that article. So it was me basically just tying to wing it in the mean time...

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Click to expand...
I'd like to know where you came up with 2 gallons of acid as the dose. It wasn't on this message board. Please don't tell me the pool store told you to dump it in using the slug method.

If you check poolmath down where it shows Effects of Adding Chemicals, in a 19,200 gallon pool with 7.2 pH and 150 TA, 256 oz of 31.45% acid will lower pH by 3.2 and lower TA by 52. Granted, for huge changes, the pH calculation isn't so good, but did you really mean to drive pH down to the 4s?
 
Richard320 said:
If you check poolmath down where it shows Effects of Adding Chemicals, in a 19,200 gallon pool with 7.2 pH and 150 TA, 256 oz of 31.45% acid will lower pH by 3.2 and lower TA by 52. Granted, for huge changes, the pH calculation isn't so good, but did you really mean to drive pH down to the 4s?
Click to expand...

Ouch, that isn't going to be good for your heat pump...
 
Richard320 said:
I'd like to know where you came up with 2 gallons of acid as the dose. It wasn't on this message board. Please don't tell me the pool store told you to dump it in using the slug method.

If you check poolmath down where it shows Effects of Adding Chemicals, in a 19,200 gallon pool with 7.2 pH and 150 TA, 256 oz of 31.45% acid will lower pH by 3.2 and lower TA by 52. Granted, for huge changes, the pH calculation isn't so good, but did you really mean to drive pH down to the 4s?
Click to expand...

No uncertainly didn't.... I thought I would bring my TA down to where it needs to be (I did use pool math for the calculations) and then if I can keep aerating the pool at the same time, I'd keep the pH up somewhat. Again, all if it was me thinking I can deal with alkalinity while chlorine levels are coming down and I can just wing it whiteout being able to test the pH.
Yes. I feel like a dumb *** now.
In the mean time I've bypassed the heat pump again.


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Maybe I have lucked out.
My FC levels are still at 15.5, by I've measured pH anyway and getting around 7.3. Hopefully it's at least in the neighborhood of being accurate since the FC levels are getting close to 10. So, maybe the continued aeration and that box of borax did help to get the pH backup to the correct levels.
The TA is still at 110, but I'm certainly not touching anything until the FC is under 10, will just continue aerate. Hopefully with sun today, the FC will be down to 10 by the end of the day, then I'll just follow the steps for getting the TA down as per pool school.
Lesson learned...


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BTW, most commercial MA has a pH of around 4.5. I doubt the calculator is anywhere near correct for such a large addition. I would guess it would be wildly low. It is 10x harder to go from 6 to 5 as it is to go from 7 to 6. My guess would be that somewhere around 6.2-6.5 would start requiring a ton of acid to show any major difference. Plus with high TA the pH should shoot up very quickly at such low levels.
 
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