PH is 7.0 - Do I need to increase it before a SLAM?

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
PH was 8.0 at opening. We must have added too much muriatic acid to the pool because it appears to be 7.0 now or possibly lower. The solution is yellow. I ran out of one of the TA solutions so I'm not sure what the TA is. Can I proceed with the SLAM tonight since chlorine will increase PH anyway or do I need to increase the PH before the SLAM? I've never had to increase the PH in our pool before since it always runs high so I do not know what needs to be done to increase it. I checked with a local pool store and they said not to worry about it but I wanted to check on here first.
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
No. 7.0 is fine. SLAM away!

FYI, best way to increase pH is through Aeration - Further Reading
If the PH is less than 7.0, would it still be fine to start the SLAM? After plugging in the amount of muriatic acid we added into a calculator, I'm concerned that PH might actually be lower than 7.0. The vial only goes down to 7.0 and the solution is yellow. Is there anyway to find out what the true PH level is with my test kit? If the PH is actually lower than 7.0, could it cause any damage to equipment or my fiberglass shell?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
17,994
Northern NJ
Depending on how low the pH is it can damage your heater core.

What type of heater do you have?

Do you have a heater bypass?

How can you aerate the pool to raise the pH?
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
Depending on how low the pH is it can damage your heater core.

What type of heater do you have?

Do you have a heater bypass?

How can you aerate the pool to raise the pH?
We have a gas heater but we never use it. I don't know if we have a heater bypass. Pointing the returns upwards is the only thing on that list that we could easily do to raise the PH. I'm not that concerned about damaging the heater since we never use it but I'm very concerned about damaging the pump, the shell of the pool or any of the fittings. Pool is getting greener and we can't see the bottom, so we need to do something about it before it gets worse. Do you think it would be safe to go ahead and SLAM if the PH is actually less than 7.0? We need to increase CYA too so I assume that might drop the PH a bit too. Other than aeration, is there something I should add to the water before doing the SLAM to increase the PH and decrease the chances of any damage to my heater or other pool equipment?
 
Last edited:

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
17,994
Northern NJ
Pump, shell and fittings are all PVC and won't be damaged by low pH.

Yes, CYA will drop the pH some. You really need to know your TA to make any adjustments to your pH. So I am reluctant to tell you to add any chemicals to raise your pH.

The usual guidance is...

If TA is 50 or above, bring your pH up to 7.4 or so using 20 mule team Borax.....soda ash is not a good choice.

If TA is below 50, then bring the TA up to 50-60 using baking soda and THEN raise your pH to around 7.4 using 20 Mule Team Borax.

You need to decide if you want to fool around with the pH or just start the SLAM Process
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,544
San Dimas, CA (LA County)
Let's get some numbers. What were the pH and TA before you added acid, and how much of what strength acid did you add? Did you use poolmath, or the acid demand test? You're used to adding acid. Did you add what seems like an extraordinary amount? It says you have a K-2006. You should have the base demand reagent. Tell us what that test says. Just measure pH then add that one drop at a time and count drops. until the pH comes up to something you can match.
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
Let's get some numbers. What were the pH and TA before you added acid, and how much of what strength acid did you add? Did you use poolmath, or the acid demand test? You're used to adding acid. Did you add what seems like an extraordinary amount? It says you have a K-2006. You should have the base demand reagent. Tell us what that test says. Just measure pH then add that one drop at a time and count drops. until the pH comes up to something you can match.
Before adding the acid, PH was 8.0. A pool store that uses a Taylor test told me that our TA was 70. (I had to rely on the pool store for the TA test only because my TA chemicals were all expired and over a year old and I couldn't wait to SLAM). We added Jasco Green muriatic acid which is actually stronger than we thought (20%) and this is not included on the pool math calculator. We used another brand of the green low-fume kind before and it was 15.7% so we assumed this one was too. That is how we made this stupid mistake. We added approximately 64 ounces of it, which would have brought PH down to around 7.4 if it had been 15.7% like we thought. I just did the Base Demand test and the color of the solution matched 7.4 in 3 drops but I'm not sure if this is accurate since this solution expired in February and is over a year old. Tomorrow I plan on going back over to the pool store that uses a Taylor test and get them to retest the TA. If it has gone down below 50, should I mess with bringing them up with baking soda and/or Borox? Or can I just proceed with the SLAM since chlorine and running the pump constantly with the returns pointed up some will raise the PH? I also need to add CYA too since it is zero but I could always buy some "Liquid Gold" at the pool store if this would prevent further declines in PH. Natural Chemistry claims that their Liquid Conditioner is PH neutral, but I don't know if this is true or not.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,544
San Dimas, CA (LA County)
Before adding the acid, PH was 8.0. A pool store that uses a Taylor test told me that our TA was 70. (I had to rely on the pool store for the TA test only because my TA chemicals were all expired and over a year old and I couldn't wait to SLAM). We added Jasco Green muriatic acid which is actually stronger than we thought (20%) and this is not included on the pool math calculator. We used another brand of the green low-fume kind before and it was 15.7% so we assumed this one was too. That is how we made this stupid mistake. We added approximately 64 ounces of it, which would have brought PH down to around 7.4 if it had been 15.7% like we thought. I just did the Base Demand test and the color of the solution matched 7.4 in 3 drops but I'm not sure if this is accurate since this solution expired in February and is over a year old. Tomorrow I plan on going back over to the pool store that uses a Taylor test and get them to retest the TA. If it has gone down below 50, should I mess with bringing them up with baking soda or Borox. Or can I just proceed with the SLAM since chlorine and running the pump constantly with the returns pointed up some will raise the PH? I also need to add CYA too since it is zero but I could always buy some "Liquid Gold" at the pool store if this would prevent further declines in PH.
That solution is pretty stable. I'd trust it. It looks like 3 drops in 20000 gallons indicates you need 1.92 lbs of soda ash. So slightly less for 19000 gallons. Stop. Poolmath says that at 70 TA, to go from 6.8 to 7.4 will need 77ounces. That's almost 5 lbs. To go from 7.0 to 7.4 at 70 TA takes almost 3 lbs. The base demand wants less than that, so your pH must be above that.

Working the other way, adding 64 ounces of 20% is the same as adding 81 of 15.7. Playing with poolmath, from 8.0pH & 70 TA to 7.1 ph calls for 96 ounces. You added less than that.

You're good. Leave pH as is and jugs away.

EDIT: Buy granular CYA at a big box store. For the first bleach, consider CYA zero and target 10 FC. Add the CYA. Target 30ish. Consider it all there even if it hasn't completely dissolved and use 12 FC as your target thereafter.
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
That solution is pretty stable. I'd trust it. It looks like 3 drops in 20000 gallons indicates you need 1.92 lbs of soda ash. So slightly less for 19000 gallons. Stop. Poolmath says that at 70 TA, to go from 6.8 to 7.4 will need 77ounces. That's almost 5 lbs. To go from 7.0 to 7.4 at 70 TA takes almost 3 lbs. The base demand wants less than that, so your pH must be above that.

Working the other way, adding 64 ounces of 20% is the same as adding 81 of 15.7. Playing with poolmath, from 8.0pH & 70 TA to 7.1 ph calls for 96 ounces. You added less than that.

You're good. Leave pH as is and jugs away.

EDIT: Buy granular CYA at a big box store. For the first bleach, consider CYA zero and target 10 FC. Add the CYA. Target 30ish. Consider it all there even if it hasn't completely dissolved and use 12 FC as your target thereafter.
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
Thanks so much for the advice, Richard. I took a sample to a pool store today and I had the manager test the PH and TA since I don't have any TA reagents. They use a Taylor test kit there and the manager seems to know what he is doing. He said that TA is 30, and PH is probably closer to 6.8 or 6.9. He recommended that I add some soda ash since it will increase both TA and PH. After learning this new information, do you still think that I don't need to increase anything before the SLAM? I bought a box of soda ash at the grocery store, in case it would help but I could return if it isn't needed. According to what you said above, that base test says to add less than 2 pounds of it if I want to increase PH to 7.2. If PH is 6.9 and TA is 30 like the pool store test indicates, that will increase PH to 7.2 but will only increase TA to 42. Is 42 high enough? If soda ash won't work, I also have a 5 lb box of baking soda on hand, but I know that it won't increase the PH much if I use that.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,544
San Dimas, CA (LA County)
Thanks so much for the advice, Richard. I took a sample to a pool store today and I had the manager test the PH and TA since I don't have any TA reagents. They use a Taylor test kit there and the manager seems to know what he is doing. He said that TA is 30, and PH is probably closer to 6.8 or 6.9. He recommended that I add some soda ash since it will increase both TA and PH. After learning this new information, do you still think that I don't need to increase anything before the SLAM? I bought a box of soda ash at the grocery store, in case it would help but I could return if it isn't needed. According to what you said above, that base test says to add less than 2 pounds of it if I want to increase PH to 7.2. If PH is 6.9 and TA is 30 like the pool store test indicates, that will increase PH to 7.2 but will only increase TA to 42. Is 42 high enough? If soda ash won't work, I also have a 5 lb box of baking soda on hand, but I know that it won't increase the PH much if I use that.
Call the pH 6.9 and target 7.2 and TA 30. It calls for 19 oz soda ash. Effects of Adding Chemicals(at the bottom of poolmath) says that will raise TA by 7. Not enough.

Just raising TA will take more than your 5 lb box of baking soda.

So add the baking soda - the whole 5 lbs. And then brush the whole pool to ensure it gets mixed and dispersed. Then test pH and if it's still low, add the soda ash. Sound like a plan?
 

nadar

Active member
Oct 21, 2018
33
Northern Tennessee
Thanks again for the advice. When I plugged soda ash into the calculator on the bottom, it says 2 pounds will raise PH by .37 to 7.27 and raise TA by 12 to 42. I know this is a bit more than the calculator on top recommends but it gets PH to the 7.2 goal and increases TA at the same time. Looks like 5 lbs of baking soda will raise TA by 19 to 49 but will only increase PH by .04 to 6.94 so PH will still be too low. If TA needs to be higher than 42, looks like it would be easier to add the soda ash first and then add baking soda if TA still isn't high enough. Is there some reason why you recommended doing it the other way around? I'd like to start the slam tonight since CYA is 0 so I don't want to have to wait to retest the PH and add the soda ash. I'd like to dump it all in, brush, wait an hour and start the SLAM.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,544
San Dimas, CA (LA County)
Thanks again for the advice. When I plugged soda ash into the calculator on the bottom, it says 2 pounds will raise PH by .37 to 7.27 and raise TA by 12 to 42. I know this is a bit more than the calculator on top recommends but it gets PH to the 7.2 goal and increases TA at the same time. Looks like 5 lbs of baking soda will raise TA by 19 to 49 but will only increase PH by .04 to 6.94 so PH will still be too low. If TA needs to be higher than 42, looks like it would be easier to add the soda ash first and then add baking soda if TA still isn't high enough. Is there some reason why you recommended doing it the other way around? I'd like to start the slam tonight since CYA is 0 so I don't want to have to wait to retest the PH and add the soda ash. I'd like to dump it all in, brush, wait an hour and start the SLAM.
The effects of adding chemicals pH change is only accurate wuithin a very narrow set of parameters. So it shouldn't be used to calculate pH changes. The pH box up above us for that.

And the reason for the order is because TA acts as a buffer. A shock absorber, sort of. It prevents wild swings. With really low TA, overshooting a little on a pH adjustment can shove the pH way beyond the target, whether raising or lowering. So if it says 2 lbs will take you to 7.2 and you add 2 lbs, you could easily end up at 7.5 or 7.6. Not the end of the world, but just another nuisance. Once TA is above 50, that risk goes way down.
 
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