Help PH and TA won't go down

[ladiekali]

ok, my well water is testing at 240 alkalinity and 7.4 ish for ph
I just tested my well water last night... in trying to figure this problem out.

my pool water is testing 140 for alkalinity
and my ph is just under 8.0

i am having a difficult time here. i add water to my pool about every two days...
I have added as much as two gallons of muriatic acid in 1 week...

the lowest my alkalinity gets is 130!

and my ph varies between 8.1 and 7.8

I can't seem to get it any lower.

I had the best luck lowering ph with ph down.

can some one help me out here.

my pool store tells me it depends on wether i walk the pool while pouring in the muriatic acid or if i just pour it in front of the jet.

yesterday morning i added a half gallon of muriatic acid. this morning it appears to have gone down from 240 to 230.
I just added maybe 1/2 quart, didn't want to add more as the kids are about to use the pool. But i figure i will add the rest of the gallon tonight.

or should i just dump it all in right now?

and with my 20,000 gallon pool, how many gallons seems right?

Now in the next day or two i will have to clean my filter and i will lose about 4 inches of water, that is going to make the alkalinity raise when i refill that water loss and I will be right back to the beginning right?

 

[woodyp]

i add water to my pool about every two days...

--Why are you having to?

my pool store tells me it depends on wether i walk the pool while pouring in the muriatic acid or if i just pour it in front of the jet.

--your pool store is nuts We recommend adding in front of a return.

High TA can cause wild swings in your PH level. We recommend lowering your PH to 7.2, then raising it using aeration, repeating until you gradually lower your TA with this process.

 

[Donldson]

my pool store tells me it depends on wether i walk the pool while pouring in the muriatic acid or if i just pour it in front of the jet.

This is a very old and very bad myth in the pool industry, that acid will affect the TA or pH depending on which way you add it. It keeps getting told yet there is nothing to support it. Add acid in front of the return, it will burn off TA and lower your pH. Your TA is driving your pH up from being so high, once you get it down below 100 it will become much more tolerable. I understand the problem all too well, my fill water TA is extremely high and I deal with this every Spring.

A bigger problem is why are you losing 2 inches of water a day? That should not be normal.

 

[ladiekali]

I'm in south georgia... i assume this is evaporation... maybe it's closer to an inch a day, i refill the pool about every other day.
it seems to be less on cloudy days, but the last few weeks here have been pretty warm and sun shiney. the pool water is already 84 degrees.

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i added the rest of the gallon this evening. tomorrow I will check the TA and add another half gallon in the morning, retest in the evening and see what happens then.

Glad to know that i don't have to walk the pool pouring acid. the splash back has been so much worse than just standing near the return jet.

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i added the rest of the gallon this evening. tomorrow I will check the TA and add another half gallon in the morning, retest in the evening and see what happens then.

Glad to know that i don't have to walk the pool pouring acid. the splash back has been so much worse than just standing near the return jet.

 

[dooger54]

Takes a while after you add acid to get the TA down. Aeration is the trick. Takes mine at least a day of aeration to get my ph back up to 7.8 so I can hit it with acid again. Have some patience.

What strength acid solution are you using? Make sure you have that right in the Pool Calc.


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[ladiekali]

it says it's 10.5 percent. but it doesn't even seem to bring the ph down. so i'm thinking i need to add more than it says to add.

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​edit.... muriatic acid is 31.45 percent

 

[Dumbled0re]

my well water is testing at 240 alkalinity

That's a big part of the problem. I reckon that means every time you add 250 gallons of such water, you need to add a pint of concentrated (34%) acid just to break even.

If you want to lower the pH and/or TA, you have to add more acid than that.

Test the acid demand, and add the indicated amount of acid. In the short run, the pH will go down.

Because of the high TA, the pH will creep back up, as CO2 bubbles out of the system. So add more acid. Every mole of acid that you add will do something useful. In the short run (or at high pH) it will lower the pH, and/or in the long run (at low pH) it will lower the TA.

As long as the pH is OK, you don't directly care about high TA. It serves as a warning that more acid will be needed soon, but there's no need to panic.

There are about 10 reasons to aerate the pool. Among other things, it speeds up the process of getting CO2 out of the system.

You might want to invest in a pool cover, to cut down on evaporation. This will cut down on the need for fill water, and hence on the need for continually adding acid. If you have a cover, you reeeally want an aerator.

TA is code for calcium carbonate. 100 ppm of TA means 100 milligrams of CaCO3 per liter of water, or the equivalent. That's very nearly 1 millimolar.

 

[chiefwej]

And use stronger acid, not the weak 10% stuff. Look for 30% and you have to use 1/3 of what you are adding now.

 

[dooger54]

it says it's 10.5 percent. but it doesn't even seem to bring the ph down. so i'm thinking i need to add more than it says to add.

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​edit.... muriatic acid is 31.45 percent

Make sure it is the 31% solution. I just bought "pool acid" at Home Depot and it's the 15% solution. Their brand.


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[chiefwej]

Our HD has both kinds, the weak 10% just cost a bit less. Not a good buy. You just have to read the label on any acid you buy. I've seen several different strengths, both at big box stores and pool stores. When compared based on cost and strength, sometimes the pool store is the cheapest. I never buy less than 28%.

 

[Tvarnell]

I like to add the acid with the pool pump off and let it be over night then retest after pump has ran a little. I have found this the fastest way to adjust ta.

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[ladiekali]

thanks for all the feedback!

i have my TA down to 120 and my ph down to 7.3

i guess i need to look into aeration.

i have one jet pointing up but it is just making waves.
I'm thinking of getting a little $25 cascade fountain. Maybe that will help aeration, and possibly keep the tempature down and fun for the kids.

I feel much better about getting below 130 TA.

it rained yesterday so that was nice, i didn't have to add well water to fill the pool.

I will try adding a quart of muriatic acid every time I backwash my filter and have to refill the pool. maybe that will help things out.

i usually run my pump at night... it keeps the mosquito's from filling up the pool, and other creepy crawlers.

 

[Dumbled0re]

I like to add the acid with the pool pump off and let it be over night then retest after pump has ran a little. I have found this the fastest way to adjust ta.

You can do that if you like, but you ought not recommend it to other folks, for at least two reasons:

1. If you try that technique in a plaster pool, the acid will settle to the bottom and do irreversible damage to the plaster.
2. Lowering the TA is not the main goal for most people. In a high TA situation:

• If the pH is OK, you don't directly care about the TA. Over time the pH may drift up as the TA drifts down, but you can cross that bridge when you come to it. In the meantime, enjoy the pool.
• If the pH is high, you still don't directly care about the TA. You care about the acid demand. Add enough acid to bring the pH down to something reasonable, then proceed as above. If you have to add a pint every day for a week, that's better than trying to "fix" the TA all at once.
• If the pH is low, aerate. The pH will come up as the TA goes down.

FWIW I cobbled up a venturi gizmo that dilutes the acid 100,000 to 1 before it goes into the pool. At that point it is much less acidic than vinegar. A couple of hours are needed for it to feed in a pint of acid, but the workload on me is practically zero. This is pretty much the opposite of adding acid without stirring.


By way of contrast, note that adding acid without stirring is a way of having relatively more impact on the TA with relatively less impact on the pH. That's because concentrated acid is super-disproportionately more effective at turning carbonates into CO2. Unfortunately the method is destructive to plaster, and for most people it's aiming at the wrong goal anyway.

 

[faby3003]

I'm in south georgia... i assume this is evaporation... maybe it's closer to an inch a day, i refill the pool about every other day.

If you're losing an inch of water per day, I don't think that is evaporation. I think losing an inch or two per week due to evaporation is reasonable.

I would look for a leak.

 

[Dumbled0re]

i guess i need to look into aeration.

I'm thinking of getting a little $25 cascade fountain.

I recommend bubbling air through the water, not the reverse. The idea is to maximize the amount of useful aeration and minimize the amount of evaporation. The point is, a tiny bubble does all the evaporating it's going to do in the first inch or so, but continues to exchange CO2, O2, and other gases as it works its way up through the water column.

A fountain or waterfall does pretty much the reverse: Maximum evaporation with relatively little gas exchange.
​

You should be able to get an "Ecoplus 5" air pump for 50 bucks plus shipping. It's quiet and reliable in 24x7 operation. It puts out plenty of air, and (unlike many seemingly-similar pumps) an adequate pressure for your purpose. Get a 12" sintered air stone from the aquarium supply store. [For a deeper pool you might prefer the Ecoplus 7.]

 

[Teald024]

Loosing an inch or more of water a day is to much. To check to see if evaporation is causing your water loss, do the bucket test.
Take a bucket, any size and fill it up almost to the top. Put it outside next to your pool, somewhere an animal won't drink from it or knock it over. Pick a time you won't loose pool water to splash out and don't backwash the filter. Leave it there for a couple of days. Come back and note the change in level of the water in the bucket. Note how much the bucket level drops. The pool level shouldn't drop any more than that. If it does, you are loosing water somewhere to a leak.



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