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what causes TA to go up?


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I did do a search but could not find this specific topic; sorry if this is a repeated question. (I suspect that it is). I did read the threads on decontamination. (which may be what I need)   

 

Simple version:

1)      What can cause TA and PH to continue to go up, even after it is down to normal range?

2)      Can it be a growth of bacteria?

3)      What causes foaming to get worse 24 hours after the last use, when there was no foaming during the use itself? (again bacteria in water?) 

Chemical status: (based on digital direct read PH meter, test strips, and a digital meter for one of the hardnes readings at the local store, forgot which one)

TA- 120

PH – 8.2

Calcium Hardness – 75

Total dissolved solids – 2-5

Running a bromine tablet floater (and crushed one tablet to start it)

Have ozone generator.

330 gallon clear water spa

Temp: 98

Water from well, but through a water softener and hose end filter.

The longer description:

I bought a used hot tub, that had been winterized by draining, no RV antifreeze used.

There was some water in the spa low points that was not nice at all.  One pool of it had scaled or changed the surface of the tub, but the other small pools caused no damage.

After mopping up the water and drying the inside of the tub, I reconnected the pump lines which had been off all winter.

On initial fill, there was a bit if a scum lines that formed and a lot of foaming. 

Tap water (from well)

PH – 7.4

TA – 240 (of higher test strip very blue)

Total Hardness (very low could be 0)

Anti-foaming did not help, so added:

-          Enzyme

-          Shocked with trichlor

-          - PH down

-          Added some calcium to get total hardness up

-          Crushed on bromine tablet

Over the next week the PH continued to go up to 8.5 in 12 hours.  I used 1/3 of a bottle of ph down over the course of a week.  I would get the PH down to 7.4 and the TA down below 120, but in 12 hours both would go up.

I shocked with trichlor, added clarifier, and antifoaming, which controlled the foaming for a short time.

Over the next week, TA and PH would go from 7.4 and a ta below 120, to 8.5 and TA high.  I used up 1/3 of a bottle of ph down in 4 days and had to buy more…..

The other odd thing is that at the end of the first use, there was a little foaming, and water not very clear.

I shocked, and added more clarifier, and things were better.  The next day I checked and PH was up, so I added PH down, and turned on jets, got foaming.  I added antifoam. 

Second use (two people) PH again high, but no foaming and clear water.

Next day PH up again, and foaming when I started the jets to distribute the PH down.

The local spa shop, recommended that I super shock for a week, so sanitize the pool, take out the filters and run a jet clean, then drain and start over.  HE wanted me to raise the chlorine  for a week, then add the jet cleaner, let it sit a day then drain.  

After reading the decontamination thread, the recommendation seems to be to run the jet clean first, then drain, super shock for 24 hours, drain and refill then a chlorine use test.   

I got the since that this guy did not really know his stuff, and was just  giving a standard answer, he gave me a sheet on super chlorinating the hot tub which was preprinted.  He also said that the test kit using drops were a waste of time and not needed.  He said that they were no more accurate than the strips. (Which leads me to believe that he really does not know his stuff)

When we talked about bromine, he did not have a clue, and said that they do not recommend or sell it. 

I am willing to super shock it, if it will solve the problem, but I am not sure that it will help.

I know that something is making foaming worse, after we get out, so maybe there is something that just needs a good sanitation.     

I am running a chlorine take up test now, and will see the results tomorrow. 

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sorry, should have tested this morning before I posted this. 

When I was at the spa shop yesterday, I left my box of chemicals there. so I did nt have any of my ph down to use.  But I did pick up some more thrichlor.  So I added 1.5 oz of thrichlor last night.  

This morning, 

my Free chlorine is 5

TCI - 10 

Alk is still 120

PH dropped to 8.0 (from 8.2 yesterday) 

I may still sanitize the pool, but this is the first time the ph has gone down and the ta has stayed the same.

I am going back to the store to pick up my chemicals, so I will try ph down tonight, 

I suspect that the bromine tables from the  floater finally dissolved  plus the tablet I crushed.  I may take the floater out and pick up some non chlorine shock, since it looks like I now have the bromine levels up and it should just need the oxidizer to work. 

Since I did not take a chlorine reading last night, I cannot calculate my chlorine use.  I will test it again tomorrow and see what happens. 

 

BUT the first few questions still stand.  

What made  the TA to go up in the first place? 

 

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Since yours is a used tub that is new to you, I would strongly recommend that you use Ahh-some to purge the plumbing and then refill and start over. You should not be experiencing the pH and TA problems that you write about, and I'm not sure of the cause, but if you wish to use bromine and use the two step or three step bromine method you should not have those problems. The guy who sell Ahh-some says that super chlorinating is not necessary. Just purge with Ahh-some, drain, clean the tub, and refill. From what I've read, there is no other product that comes close to the effectiveness of Ahh-some.

You are right not to trust the information you receive from the pool store guy. The pool stores make their money by selling you expensive things (for instance, they will sell you baking soda for ten times what you would pay for it at the grocery store), and it's often exactly what you don't need. It's probably not even the guys fault, but the culture of the stores, which teaches him all sorts of things that are partially or blatantly false.

If you want to manage your tub well, you should educate yourself by reading as much from the sticky posts and archives in this forum and in the Trouble Free Pool forum as you can. From your above posts, it sounds like you've been throwing things at your tub without understanding exactly what they do or what the consequences are.

If you intend to use bromine in your tub, you should not be using trichlor. For the three step method, you basically need three things. 1) Sodium bromide added once for each time you fill the tub, to build a bromide bank, 2) an oxidizer, which can be either chlorine from standard household bleach, or non-chlorine shock, potassium peroxymonosulfate (MPS), and 3) bromine tablets (BCDMH) in a floater. To keep the water balanced and reduce the possibility of foaming you may need to increase the calcium hardness with calcium chloride, and adjust the pH and total alkalinity with baking soda, washing soda, or borax for increasing, and dry acid or muriatic acid for decreasing. The only items you will need to buy from the pool store or online supplier are sodium bromide, bromide tabs, MPS if you choose to use it, although bleach is less expensive and works just as well, calcium chloride and maybe acid.

I have a bromine three step tub, and I use sodium bromide, 8.25% bleach from Walmart, and BCDMH tabs in a floater. I also use baking soda to raise pH and TA when needed, because bromine tabs are acidic and tend to bring the pH and TA down. I had to add calcium chloride because my well water for fill is very low in calcium, about 10 ppm. I also added borates to help stabilize the pH. But I never need acid because my pH and TA tend to go down slowly and never go up.

Also, I would recommend you get a good test kit. For bromine, that would need to be the Taylor K-2106, or for chlorine the Taylor K-2006. This will include the FAS-DPD test for bromine (or chlorine). This is the only accurate way to keep track of your hot tub chemistry. Test strips, and less accurate drop tests such as DPD and orthotolodine, are not accurate enough. Once again, the pool store guy had the truth exactly reversed.

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I appreciate the reply.

I have spent time reading up, and a little smarter now than a week ago, but I have a long way to go. 

I did the chlorine uptake test; the free chlorine went from 10ppm to 5ppm in 24 hours.  A 50% drop, not too bad. 

My TA finally stabilized in the past 24 hours, the last shot of acid took it from 120 to 80, and my ph went down to 7.4,  24 hours later, ta was still 80 and ph only went to 7.6.  But I had run the pump that has the blower on it to cycle the water, so some ph rise can be attributed to that.

It took over 20 oz. of ph down to get the TA stable from a fresh fill.  I will probably get some muriatic acid for the next time.  I need to get the ta down and ph for the disinfecting cycle.  I hate to go through another 20 oz. of dry acid to get the ta down a second time.

I did read the post on lowering TA.  I think that my initial problem is that my starting TA was very high, and it simply tool time and acid to get it down. I was I am using test strips, so the color change may not have been hard to read. I think that I simply had very high TA to begin with and it took that much acid to get it down. 

I still get foaming, so I am going to run through the disinfection cycle in the stickie.

I have the filters out, and I am running jet clean now.  I will cycle the jets a few times today and let it work overnight.  Tomorrow, I will drain and clean the interior.

Then overfill. I will take a few days to get the TA and PH down and under control.  I will keep chlorine in the pool while this is happening. Once I have the TA under control,   Then I will get the chlorine up to 50 for 24 hours. 

I may use peroxide to neutralize the chlorine, so I do not have to use the acid to get my ta down again.

Then I will put in the N2 cartridge.

I will get the Taylor kit on order today. (No one up here has them in stock). It looks like I want the K-2006 test kit if I am doing chlorine.

I picked up a SunPurity  from Sundance spas, (basically a silver ion system.) I the box had the N2 logo on it.   I will try it and use MPS and some chlorine shock and see how it goes.  In Dallas I have an  electrode based system that added silver and copper to the spa.  I use to use it with a shock and was pretty happy with it.   I just hang the electrode in the fill basket and turn it on until the cu is in range, then take it out.   At least with it, I could test for copper and have some confidence that the silver was also there.  I do not like having a component of my sanitation system that I can not measure to be sure it is there.  I do have the ozone generator as well.  I am thnking of adding a uv light system in line as well, but that will have to wait until I get the chemistry under control. 

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Well, after the jet clean ther was a lot of gunky slime around the pool, so it was needed.

I drained the spa, and thought I did a decent job of flushing the lines

  • .  I used a shop vac and sucked out each port.

  •  I then put it on the blower side and blew air in the jets

  • .  I took the hose and ran water through each jet

  • Again used a shop vac to suck out the water, and blow out the lines

  • Then I refilled the spa.  The PH was fine and alkalinity was reading ok.  I do not have my Taylor test kit yet, so I raised the chlorine with shock until  strips were off of the chart, then added some more.  When I turned on the jets, it looked like a bubble bath.

  • I guess that I did not do enough rinsing.

  • I kept the chlorine up for 24  hours, and then drained the tub, 

  • More shop vac blowing and sucking.

  • I added enough water to run the pumps, and ran each of them very briefly. And then drained, sucked and blew out the lines and rinsed a third time.  

  • Then I filled the tub.

  • NO FOAMING,

  • But TA very high (as expected)

  • PH went from 7.6 to 8.5 in 4 hours.

  • I added some MPS (MSP??)

  • I used the last of my dry acid and went out and picked up some more.

  • I also got a gallon of “safe muriatic acid” which is 20% vs 12% for the regular stuff (if I remember correctly).

I have added 1 oz. of muriatic acid and checked the PH, it dropped a little but not much.  Over the next hour, I added 2 oz. of muriatic acid at a time, and checked the PH several times.  It would settle after dropping a few tenths.  I eventually got it down to 7.3, and decided to let the blowers run for a few cycles and check it in a few hours.

From what I read on another post, 1 gallon of muriatic is 11 or 12 pounds of dry.  If I am doing the math right.  128 oz. (1 gallon) is (12 pounds * 16 oz. or 192 oz.) of dry.  Each oz. of muriatic is .66 oz. of dry.  If the safe muriatic I found is 20% vs 12% then 1 oz. of muriatic is about .4 oz. of dry. 

 

I wear gloves around the muriatic.  I also pour it into the measuring container outside.  I then add it to a gallon of water in a 2 gallon bucket (so it is not very full), so it is much diluted quickly.  I then pout the diluted into the spa. 

 

I have a salt water pool in Dallas, and have to use several cups of muriatic acid ther weekly to keep the PH in range, so handling the stuff does not concern me.  At least if I do spill some on me, I can jump in the spa to quickly rinse it off. 

 

Right now the TA is still off of the chart using the test strips.  I have a Taylor test kit on order, so I should be able to get more accurate numbers soon.

I do have a digital PH meter that I got on eBay for less than $10. It came with chemicals to calibrate it, but so far the reading are in the same range as the test strips, so I think that I am getting good PH readings to the tenth. 

 

I appreciate your time, and am still learning a lot.  But I think that at least I now understand what is happening with the chemistry.   

 

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