In my reading here I understand some pools just use a lot of acid and at 19 months old my plaster may not be fully cured and adding to the problem. However I only used about half as much acid last year and the SWG was just added in May so I am thinking it is the major culprit to my high acid demand. One thing I have no clue as to why it is happening, my TA drifts up with the pH. I started this spread sheet posted by another TFP member when I got my TF100 Kit. (I was previously using a Taylor K-2005.) Blanks mean test not taken. We have had a little rain around the 12th. Any suggestions on how I can lower the acid demand? How low can I take TA safely? 30-40? Why is TA drifting?
High Acid Use
- Thread starter frankgh
- Start date
I don't think you should go lower on the TA than 60.
Do you have high TA in your tap water, and do you have an autofill system? Or have you manually been adding water that could be increasing the TA level?
Do you have high TA in your tap water, and do you have an autofill system? Or have you manually been adding water that could be increasing the TA level?
TA moves with pH. If you compare the pH reading with the TA reading, you'll see that it's pretty consistent.
Do you have a constant source of aeration, such as a spillover spa, waterfall, wind or have your returns adjusted to break the surface? Rain will also be a source of aeration. As I recall, these can lead to an increase in acid demand. What is your actual MA usage and how often do you add it? I noted you recently brought up your CYA to the recommended range. That will go a very long way to reduction in the SWG percentage and keep your acid demand a bit lower.
- May 3, 2007
- 16,828
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
The only way TA can rise is if something is being added to the pool. This is usually casued by the fill water as FSP pointed out and will usually cause a rise in PH as well but the SWG will make it even worse due to the aeration caused by the Hydrogen bubbles. So if you experience a rise in PH without a rise in TA, it is likely to be the SWG and other sources of aeration. If you are getting a rise in both TA and PH, it is probably both the fill water and SWG/aeration causing the problem.
My fill water has high TA but none has been added. TA is drifting up with pH. I say again, no fill water has been added. The only thing that has been added to the pool in the last 2 weeks is MA. I have no water features, no aeration, no kids spashing, just the SWG. There was a small amount of rain on the 12th but the TA held at 60 after that event. 4 gallons of MA in a 2 week period just sound crazy...
Do you have an auto fill system, or have you been adding water to the pool manually? If so, you should test your fill water to see what the TA level is.
I wouldn't ever lower TA below 50, and 60 is safer.
I wouldn't ever lower TA below 50, and 60 is safer.
Hi Jason, Like I said before no fill water has been added at all. None, Nada. There is no auto fill. I guess I'm lucky TA is drifting with pH, with the amount of MA added it should be close to zero!
- May 3, 2007
- 16,828
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
duraleigh said:
Not always. PH can rise without TA going up such as when aeration occurs. However, when TA rises, PH usually goes up with it. Also, when an acid is added both TA and PH will drop.
But like I said before, you cannot get a TA rise without something (carbonates and bicarbonates) being added to the pool somehow. Aeration does not affect TA. Borax, Baking Soda, Soda Ash, etc will all raise TA to some extent as well as PH but TA does not rise on its own.
reebok
0
have you looked at the concentration on the acid bottles lately? some people have found their stores getting lower strength MA for the same price.
Does your pool have rocks as the edging? Have you seen any wearing of those rocks, if so?
No rocks on the edges, acid is 34%. It has to be the plaster still curing, I guess... Maybe I just need to give it a few more months? It was only plastered Dec 07...
BTW, thanks to you all for chiming in. The folks at Ace hardware are looking at me weird when I keep buying acid 6 gallons at a time! Luck for me, they are selling them for under $4 a gallon.
BTW, thanks to you all for chiming in. The folks at Ace hardware are looking at me weird when I keep buying acid 6 gallons at a time! Luck for me, they are selling them for under $4 a gallon.
reebok
0
New numbers for today
PH 7.8
TA 50
CH 550
Free CL 4.8
CC .2
CYA 60
Borates 30
Salt 3000
PH as risen .2 a day, every day no matter what the SWG is set on. I went 2 days with it off and the rise is the same. This is the first week that TA did NOT go up with PH. Normally TA will come up with ph, when ph hits 8 ta is up to 80. We have had a butt load of rain the past few day so I can see why CYA has fallen off a bit. CH has gone up from 2 months ago, it was right at 380 for the longest time so I have not been checking it. It is now 550. I checked it twice. Yes, it is a TF test kit and Apollo stirrer. My routine is to let the ph get to 8 and add a half gal of acid. Then repeat every 2 days. If I'm going to be out of town, I'll let it get to 8 then add a gallon which gets it down to near 7. There it will be good for 5 days. Is adding so much acid all the time doing something to the plaster making CH go up? Is something blowing into the pool I can't see effecting the water? Plaster was done in Jan 08 and when using the off-line CL with pucks, PH would come up but slowly. So little, I don't remember putting acid in very often at all. Anyone else seeing an acid demand like this with 22 month old plaster and a SWG?
PH 7.8
TA 50
CH 550
Free CL 4.8
CC .2
CYA 60
Borates 30
Salt 3000
PH as risen .2 a day, every day no matter what the SWG is set on. I went 2 days with it off and the rise is the same. This is the first week that TA did NOT go up with PH. Normally TA will come up with ph, when ph hits 8 ta is up to 80. We have had a butt load of rain the past few day so I can see why CYA has fallen off a bit. CH has gone up from 2 months ago, it was right at 380 for the longest time so I have not been checking it. It is now 550. I checked it twice. Yes, it is a TF test kit and Apollo stirrer. My routine is to let the ph get to 8 and add a half gal of acid. Then repeat every 2 days. If I'm going to be out of town, I'll let it get to 8 then add a gallon which gets it down to near 7. There it will be good for 5 days. Is adding so much acid all the time doing something to the plaster making CH go up? Is something blowing into the pool I can't see effecting the water? Plaster was done in Jan 08 and when using the off-line CL with pucks, PH would come up but slowly. So little, I don't remember putting acid in very often at all. Anyone else seeing an acid demand like this with 22 month old plaster and a SWG?
As first responder to your most recent post I'll go out on a limb a bit... don't know why your Calcium Hardness increased since your original July post, but it's well outside recommended levels. My first instinct would be a partial drain/refill to get it down (check your fill water first to be sure CH is not some ungodly high figure, say, over 300.)frankgh said:
Second thought: Maybe your pool likes a higher pH (not very scientific, I know) -- have you run the numbers through the Pool Calculator? If you're reasonably balanced, maybe the acid demand isn't something to worry much about.
Other, wiser heads on this forum may wish to add or subtract from this rumination. If they object to these observations, feel free to discard them.
Good stuff Poly 
This thread has my head scratching
On the CH 550 is high but manageable, just don't let your PH go beyond 7.8. Letting it go to 8, like you have in the past could now cause calcium scaling.
On your TA issue, given your pool has had time to cure, I'm thinking there may be an issue with your TA test numbers. Can you do me a favor and repeat the TA test, but before each drop added, wipe the dropper with a damp paper towel? There have been reports that static charge has affected the size of the re-agent droplets. Try that and see if your TA is really 60.
Hope that helps
This thread has my head scratching
On the CH 550 is high but manageable, just don't let your PH go beyond 7.8. Letting it go to 8, like you have in the past could now cause calcium scaling.
On your TA issue, given your pool has had time to cure, I'm thinking there may be an issue with your TA test numbers. Can you do me a favor and repeat the TA test, but before each drop added, wipe the dropper with a damp paper towel? There have been reports that static charge has affected the size of the re-agent droplets. Try that and see if your TA is really 60.
Hope that helps
Yeah, me, too.
I don't think the redo of the TA test will shed any light. The issue with that test is that the R-0009 reagent (and only that reagent) has a tendency to develop a static charge between itself and the bottle that contains it.
The result is that the drops "leap" from the bottle before they are fully formed.....causing the drops to be smaller. The result is a false high test result.
Wiping the dropper tip seems to consistantly cure the problem. I can't think of an instance where that issue would cause a low TA result.
It's w-a-a-a-y above my pay grade but can a condition exist within the plaster where it never really cures (or cures abnormally slow) so is constantly throwing off calcium and creating a pH rise?
- May 3, 2007
- 16,828
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
duraleigh said:
Sherlock Holmes said:
So if there has been no fill water added, no features to dissolve and rain water generally does not add calcium (it can raise PH though), then the only possibility is the pool surface dissolving which is not a good situation.