Can muriatic acid go bad AKA My muriatic acid seems to be doing absolute squat

[mjustison]

Hi,

I'm about a year into pool ownership and I figured I had it fairly down. However in the past week or so my pH has been causing me a lot of trouble. I just can't keep it lower than the upper 7s.
Latest readings as of this evening:
Cl - 4ppm
pH - 7.7-7.8
TA - 200 (I'll get to this in a second)
CYA - 55-65 (honestly it's hard to tell what is *just* visible with the Taylor 'watch the dot disappear' test)

A bit more background: ~7000gal round, cartridge filtered.
I just replaced filters so the water in the pool is just rocking like its nobodies business. Also it's been getting pretty hot (upper 80s to mid 90s during the day). Other than that all has been about the same.

So the past few evenings I'd come home and the pH would be easily past 8, so I'd dump like a quart of MA into the pool and expect to wake up and see it hovering in the 7.4 range. More often than not it barely dents it or it actually gets worse.
It's probably affecting my ability to keep chlorine in the pool as well but it's not as big of an issue. It doesn't seem to disappear like my MA does.
I last checked the TA around the end of June and it was in the 125ppm range. Not terrible but not that great either. I thought MA was supposed to lower TA but I measured it this evening and its a whopping 190 or 200.

I get my MA from lowes in two gallon boxes and I know I've had a dud chlorine from them in the past (same brand as MA). Is it possible that the MA is just no good? The stuff I have looks right. It's yellowish but it doesn't have a smell. I thought hydrocholoric acid had a smell...maybe I'm wrong.

I *did* have some ph down on hand and I threw about 24oz of that in a few days ago. That seemed to work. It got things down to around 7.3-7.4 for a day or so. What would cause the pH to shoot up so high so quickly?
I've never had trouble with MA until now. I'm just wondering if something has changed and it isn't the acid that I'm using.

Thanks!
-Mark

 

[zea3]

What is the strength of the MA? It should say on the label. It is possible you bought low strength MA and it will take more of it to be effective. To lower the TA when it is that high it will take multiple doses of MA. Keep using PoolMath to determine how much acid to add every time you test. The pH could have been well above 8 since that is where the test vial tops out. As long as the TA is high the pH will continue to climb.

 

[PoolFool.]

I know most will say MA doesn't go stale or degrade with age. A[FONT=arial, sans-serif] prior thread on here contained LOTS of those opinions.
While doing my borate thing with Borax I'm convinced I got a stale gallon of MA from my hardware store. Unexpectedly high pH after adding in several boxes of Borax and the MA.
It just didn't have that offensive burning and acrid smell to it as I poured it into the pool either.
So my experience was yes, it probably can go bad. I use he 20 deg Baume, and it usually is quite offensive to pour in. Did yours seem like it was the same strength as previous bottles?
I was doing a lot sequentially, for the borate bump.
Some of the bottles on the shelf at the store were REALLY dusty.[/FONT]

 

[Bama Rambler]

...It's yellowish but it doesn't have a smell.

Trust me, if you can stand to 'smell' it, there's something bad wrong. Even a brief sniff and your nose will burn and your eyes will water.
They make a 'friendly' version that's a lot weaker and doesn't smell nearly as strong, so you have to use a lot more of it to bring the pH (& TA) down.

As for your TA rising, what is the TA of your fill water? Maybe the utility changed the source or maybe it's always been a high TA source.

 

[mjustison]

My tap TA is about 175. When I refilled last year I managed to get this down to 125. Since it has been hot I've been filling from the tap more often. It just seems like it spiked very quickly from 125 when I tested a month ago.

Is MA preferred to dry acid? It's only like $6 for two gallons usually compared to $20 for 10lbs of dry acid. However from the pool math calculator trying to get it to do the equivalent thing requires less dry acid by volume than MA. Are there downsides to using dry acid over MA?

BTW I checked the concentration of the MA I use: 14.5%

 

[mknauss]

Muriatic acid is cheaper and adds no unwanted items to your pool water. You are using half strength. Full strength is 31.45%.

Dry acid is sodium bisulfate. It adds sulfates to your water that at higher concentrations can destroy concrete and metal.

Each time you lower you pH from 7.8 or 8 to 7.2 it will reduce your TA.

 

[PoolFool.]

Trust me, if you can stand to 'smell' it, there's something bad wrong. Even a brief sniff and your nose will burn and your eyes will water.
They make a 'friendly' version that's a lot weaker and doesn't smell nearly as strong, so you have to use a lot more of it to bring the pH (& TA) down.

As for your TA rising, what is the TA of your fill water? Maybe the utility changed the source or maybe it's always been a high TA source.

Thanks, mystery solved for my borax-ination!

Now the real question is why I didn't read more about borates earlier and add borate with a product that did not need that MA like borax requires? The bio diesel suppliers seem to supply that stuff inexpensively.

Second question, is why 20 Mule team boxes keep shrinking so much? Maybe they should be dry cleaned instead of laundered? Kind of like the race to the bottom in 6 % chlorine being most of what is available now. Great for someone's bottom line, bad for my pool budget.
The way I see it is the stores just doubled their transportation costs per amount of chlorine. Most of what they are shipping is water jugs anyway, they just reduced the chlorine content considerably.

 

[cfherrman]

I have high ta water, my pH has be in the upper 8's a lot. Usually 8.7. that's over a half jug of 31% to get it to 7.6 pH.

Add acid and check 30 mins after. Use the Taylor acid demand to get a good idea on how much acid to use.

 

[PoolFool.]

I have high ta water, my pH has be in the upper 8's a lot. Usually 8.7. that's over a half jug of 31% to get it to 7.6 pH.

Add acid and check 30 mins after. Use the Taylor acid demand to get a good idea on how much acid to use.

How high is your TA? ou could lower that with the MA and then aerate to raise the pH if you want to try to eliminate the pH rise. With that much acid demand though I'm not sure why your TA has not already plummeted.

 

[cfherrman]

Was over 300, my fill is 200 or 250. Im over due for testing the pool but with a bunch of rain I might be under 200

 

[PoolFool.]

Yikes,
I think I'd start pumpin my rainwater out of the gutters in the pool with that kind of fill water.
I've been watching several homemade aerators threads here.
I like the idea of an independent pump, so a plastic body pool scratch free sump pump can do the trick (I'd still be tempted to sink it in a 5 gallon bucket. 15 dollars in PVCand you're in business.
Or for the impatient kinds I truly loved the pressure washer idea!

Ways to boost your pH after killing your TA with 31.45 Muriatic Acid.

 

[cfherrman]

I'm down to 175 ta in the pool, pH was 8.8

 

[Dirk]

Please don't test the strength of your muriatic acid by smelling it, or suggest others do so. MA and its fumes can cause irreversible damage to soft tissue. Compared to your lungs or your eyeballs, a gallon of MA is dirt cheap. If you suspect it is ineffective, then dispose of it properly, and replace it. Six bucks.

If you really want to test it's effectiveness, without harming yourself:

- Test your pH.
- Use PoolMath to calculate the MA dose to lower your pH by "x" amount.
- Safely add that amount of MA to your pool.
- Circulate the pool for an hour.
- Test your pH.

If the difference between the results of your two pH tests is "x" amount, then your MA is fine. If not, replace it.

You eyes, nose and lungs will thank you.

If you can't dose your pool with MA without getting it in your nose, then you need to find a better way to do it.