Muriatic Acid Everyday?

[Andie]

OMG, all I do is add MA to my SWG pool. I got a test kit as was having difficulty with the strips. Now all I do is add MA to get my Alk lowered. Now that I finally have my Alk at a nice level (90) my PH is high (7.8 today, 8.2 the past couple days). My main problem has been trying to get my Alk at a good level. It seems to like to hang out at 150. I have not been having trouble with PH until now. Now that I have my Alk at a nice level and it has been since the 11th, my ph is now high. UGH!!!!!!! I am getting so fed up as all I ever do is add MA. Everything else looks good, Chl is 2.0. Cyna is 40 salt is 3500. Never seem to have a problem with these. Is this normal?? To be adding this much MA to a pool? I have been documenting everything on my calander and man it is full of add MA. And my kids are always complaining of their eyes itching which was never a problem when we thought our pool was low maintance and rarely tested it. **we are pool newbies and did not know their was any mainatance with SWG as we were told they are little to no maintaince - haha! Can anyone give me some insight??? Thanks so much!

~Andrea

[chem geek]

It is very common for SWG pools to have a strong tendency to rise in pH. Though you'll hear some pool people say it's due to the chlorine generated by the SWG being basic/alkaline, that really isn't true since the initial addition of chlorine makes the pH rise, but chlorine usage makes it drop and these cancel each other out. The real reason for the pH rise is that the SWG doesn't just produce chlorine, but also produces tiny hydrogen gas bubbles (you can readily see these if you turn on the pump and SWG at night with a pool light where you'll see lots of tiny bubbles coming out of the returns). These bubbles aerate the water pulling carbon dioxide out of the pool and into the air. Pools are intentionally over-carbonated, like a tasty carbonated beverage, though obviously not nearly as carbonated. This is what TA is (mostly) -- carbonates in the pool. This excess of carbon dioxide in the pool gets outgassed into the air and this process causes the pH to rise with no change in TA.

So, when you then add acid, you lower both pH and TA. So over time, the TA will drop (but that's not what you are seeing so I'll talk about that in a bit). The pH goes up, you add acid which has pH and TA go down, pH goes up again, etc. with the long-term result being a lowering of TA. The rate of outgassing of carbon dioxide is faster when the pH is low, the TA is high, and there is more aeration.

Now what does not make sense in your situation, relative to what I just described, is that you describe not only a rise in pH, but a tendency to rise in TA as well. You say that the TA is now 90, but will rise until it hangs out at 150? If you are measuring both when the pH is the same each time, then the only way this can happen is if carbonates are being added to the water. You aren't adding any pH Up (sodium carbonate) or Alkalinity Up (sodium bicarbonate) to the pool, are you? What other products are you adding to your pool? Perhaps one of them has carbonates in them -- I can look them up if they have a Material Safety Data Sheet (MSDS) online or you can look at the ingredients on the bottles.

Anyway, the way to lower the pH rise is ironically to have a low TA. Another thing you can do if your pool is in direct sunlight all day is to raise the CYA level higher to 70-80 ppm and also raise the FC level to 3-3.5 ppm. The other thing that can be done is to add 30-50 ppm Borates (that is adding 20 Mule Team Borax plus Muriatic Acid) which is an additional pH buffer and is also an algaecide. If your chlorine is fighting algae, then the borates will help and allow you to turn down your SWG runtime which will reduce aeration and outgassing and pH rise; same thing is true for the higher CYA level which protects the chlorine from breakdown from sunlight. But for now, let's find out what's getting added to your pool to have the TA rise (we know why the pH rises). By the way, what I'm proposing with the Borates is the same thing as what is done with BioGuard Proteam Supreme (which is essentially Borax with less water "hydrate crystal" content).

Richard

[Andie]

Oh. lord...reading your post made me dizzy . Okay, I am not adding anything other then salt and MA. Every once in awhile I will add The Blue Stuff for metal but that has not been in awhile, like 2 weeks. I will give you a quick run down:

Su 7-1: ch 2, ph 8.2, alk 190 = added MA (1qt)

M 7-2: ch 2, ph 7.6, alk 180 = added MA

T 7-3: salt added and 1qt MA

W 7-4: nothing added

TH 7-5: ch 3, ph 7.8 , alk 150 = added MA ( 1qt that day)

Fr 7-6: ph 7.6, alk 130 = added MA (1qt)

Sa 7-7: 1qt MA

Su 7-8: ch 2, ph 8.2, alk 130, CY 30-40 = add MA (1qt)

M 7-9 : **not sure why but just checked alk 110 = add 1qt MA also salt added

T 7-10: ** again just checked alk 110 = add 1qt MA

W 7-11: ch 2, ph 7.2, alk 90 ***YEAH everything looks so nice so added some medal solution 4 ounces

Th 7-12 - Sat 14th - no testing

Su 7-15 - ch 2, ph 8.2, alk 100 (acid demand stated to add 1 pt of MA)

M 7-16 - ch 2, ph 8.2, alk 100 (again with 1 pt)

Tu 7-16 - ph 8.2, alk 90 (acid demand stated 1 cup of MA)

W **today** ph 7.8, alk 90. (acid demand stated 1 cup of MA)

**This is just the month of July** For June my ph stayed around 7.5 according to the strips as I only got my kit at the end of June. My alk seemed to fluctuate b/w 120 and 180 **again the strips** and only once went below 100.

So there it is.

I live in South Texas so it is HOT here. My pool is in direct sunlight all day. Do you suggest rising my CY?? Even though it appears to be at a good level? Now I do have a stabilizer but have never needed to use it as I thought that I only needed to use this if my CY or ch is low. My chlorine levels stay pretty good. Only once was it super low and I had taken a sample into the pool store and they told me to shock it, which I did on June 15th. I have had the pool since beginning of April and this is the only time that I have shocked the pool. And I have only added the metal solution I think twice. So, since I have had my pool, the only thing we have added are salt, MA, one shock treatment and the metal solution. Right now I turn my SWG for 9 hrs at 80%. My pump goes at 2200 rpm's and 2500 rpm when cleaner is on for 2 hrs.

Okay, I think I have given you all the information I can possibly give. Honestly, if this were your pool what would you do? I feel like all I do is test the pool and add MA. Like stated before, my kids have been complaining alot the past month that their eyes hurt and prior not a problem. This one reason I decided to get a SWG b/c it was gentler on eyes,skin, hair oh, yeah and b/c it was "low" maintance. None of this is happening. I am frustrated beyond belief and feel like I have not a clue what I am doing. Please help!!!!

~Andrea

[chem geek]

Sorry to make you dizzy. Your use of test strips explains some of the TA variability. Test strips are not accurate with a few exceptions (test strips for Borates and for Salt are generally accurate -- both from AquaChek). Your TA has actually been dropping, just as predicted. Notice also how the total amount of acid needed has been dropping with the lower TA -- that is a good thing. So the first thing I would do is get yourself a good test kit, the Taylor K-2006 from Taylor here or from Leslie's here or the even better TF-100 test kit from tftestkits here. It's much easier to maintain a pool and solve problems when you have accurate information. You will even do a better job than most pool stores!

By the way, if you have any water aeration features, such as waterfalls, spillovers, fountains, etc., see if you can turn them off and see if that makes any difference in preventing the pH from rising. Also, if you have a pool cover, then use it and see if that helps (sometimes it does, sometimes it doesn't -- it depends on whether those bubbles escape from the return into the air or stay under the cover).

I suspect that your kids are complaining because the pH is getting high. A pH of 7.5 is closest to human tears and up to 7.7 is still OK but above that (or low pH below 7.3) may start to sting the eyes.

The main thing you want to try and do is to lower your SWG production, but you can't do that unless you lower your chlorine usage. I do suggest raising your CYA level -- first raise it to 60 ppm and we'll see how that goes (we may end up going to 80 ppm eventually, but no higher than that). You will also need to target 3 ppm as your Free Chlorine level, but to accurately test that you really have to get one of the test kits I referred to above -- the strips just aren't good enough (even the standard color tests for chlorine aren't good enough). So get the test kit first since we need to accurately know what your current CYA level so we know to add the correct amount (which we will likely add by using Dichlor, which is chlorine and CYA, rather than just adding CYA alone -- that way we can shock your pool as well). So the following is what we will plan to do, but start by getting the test kit. Do not do the other steps until you report your full set of numbers -- I will then be able to tell you exactly how much you have to add of each chemical.

1) Get a good test kit.

2) Add CYA and also shock the pool by adding Dichlor powder/granules to get the CYA to 60 ppm. Once the CYA level is reached, we may continue to shock the pool with bleach or chlorinating liquid until we're sure there is no unusual chlorine consumption (FC holds overnight and no measured CC).

3) Target a 3 ppm Free Chlorine (FC) level -- see if you can lower your SWG on-time (output level) to do this (because the CYA should cut down chlorine usage; if so, then the pH should rise more slowly)

4) Lower the TA level even lower using a low pH and aeration with acid procedure (I'll describe that more later if we get to this)

5) Add 30-50 ppm Borates to the pool both as an algaecide and as an additional pH buffer

We may not need to do all of the above -- we'll see if the first few steps help enough. The good news is that once your pH becomes more stable, maintenance will be much easier. You will still likely have to add acid to your pool once in a while, but it won't have to be nearly as frequently -- hopefully we can get the test and acid down to just once a week or even less.

In addition to the full set of tests from the test kit, with Free Chlorine (FC), Combined Chlorine (CC), pH, Total Alkalinity (TA), Cyanuric Acid (CYA) and Calcium Hardness (CH), I also need to know the size of your pool in gallons (if you know it; otherwise, the shape and width/length or diameter and average depth) and whether it's a vinyl or plaster/gunite pool and the kind of filter you have (cartridge, sand, or DE).

Don't worry, your problem will be solved soon and I'm sorry I overwhelmed you with technical detail. I'll try and focus just on solving the problem, not explaining how it works.

Richard

[Andie]

Richard, first of all thanks so much for holding my hand through this. I am just overwhelmed. Uh, did I mention I never did well in chemistry class.

Okay here we go. I have about a 13,000 gallon pool. I have pebbletc and a DE filter I do have a waterfall and bubbler so I will turn those off. No pool cover.

I do have a test kit now. It is a poolmaster inc. basic 4 test kit (ch,ph,alk and acid demand). When I went in to buy a kit I was told this one was great and easy to use. Is this not good enough??? I use my test strips for harndess and CYA. As of 10m ago my readings were **I put in 1c MA at 8am:

per kit: ch 2, ph 7.6, alk 90 ***looks good, right????

strip Instatest6: cya 40, fci 1, tci 3, alk 40, ph 7.2, hardness 50

strip hth 6 way: cya 30-50, fci 2, alk 80, ph 7.5, hardness 100

You said I needed to "lower your SWG production, but you can't do that unless you lower your chlorine usage". Okay, I don't know what this means. Do you mean instead of 80% on intellichlor, use a lower %?

You said to up my CYA by using dichlor. Is that the RAM stabilizer that I have? That is what pool supply gave me when I asked about raising CYA. It (canister) says it is 100% CYA. So, I do this to get a reading of 60 then I shock it? Can you give me the dummy process to do this? Such as if I add the stuff for CYA tonigh (how long to have pool run?) . Test pool in the am??? If not, add again? nx day check? Once I got it at 60, shock the pool (how long to let run?) then test the next day? see if I can get a 3ppm ch reading. If not, do I shock again? During all of this, is it okay to swim in pool? Say if I add the chem. at night, is it okay to swim by following afternoon (I have 2 kids and it is HOT here).

You said "see if you can lower your SWG on-time (output level) to do this". Does that mean to decrease the currently 80% ??

So Richard, what do "we" do now? Thanks again for your time in helping me turn my muriatic acid pool into a salt water pool.

[chem geek]

I am sorry to say, the test kit you have is not good enough. You really need to accurately test your CYA level and the test strips won't do that. Also, the test kit you have for chlorine is probably a DPD test where you look at the intensity of red color (or it could be OTO where you look at the intensity of yellow color). These will not measure chlorine levels above 5 ppm so are no good to know if shock levels of chlorine are maintained (there is a "dilution" method to test high chlorine levels, but it's not accurate). So I still suggest you get one of the better test kits I mentioned. The chlorine test in those better kits is called FAS-DPD where after adding powder to turn the sample pink, you simply count drops until the sample turns clear -- then multiply by 0.5 or 0.2 depending on sample size and you've got an accurate Free Chlorine reading AND you can then add another reagent, turn pink again, count more drops and get an accurate Combined Chlorine reading. You'll also get accurate tests for Calcium Hardness (CH) and Cyanuric Acid (CYA) that should be better than your test strips, and yes you'll get similar tests for pH and Total Alkalinity (TA), though even the pH test might be better (Taylor, which also makes the reagents in the TF-100, uses a better reagent for pH tests that avoids some chlorine interference).

I would feel really bad if we added CYA only to find out that it was already high and that the test strips gave us a false low reading. If you want to do some of the other things in the meantime, like lowering the TA even more, we can do that, but given your direct sunlight in southern Texas, I really think the higher CYA level will help -- I just don't want to go too far.

As for lowering SWG production, yes I mean lowering the 80%, but you can't do that yet -- this is what we want to be able to achieve through the higher CYA levels (and maybe adding Borates) to lower chlorine consumption. With lower chlorine consumption, you can lower the SWG chlorine production (i.e. it's output or percentage on the Intellichlor). So don't change that yet -- I was just preparing you for what we hope to do IF with higher CYA you find that the chlorine level rises well above 3 ppm.

Since you already have stabilizer, we can use that first. I mentioned the Dichlor because it dissolves much more easily than CYA, but I forgot you said you already had stabilizer. After we measure the accurate CYA number, then we will add your stabilizer by putting it into a sock or panty hose and putting it over a return -- CYA takes a long time to dissolve unless you have lots of water flow over it. With this technique it should dissolve in a day or two instead of taking a week. You might have to hook up a pool pool to dangle over the edge or something like that to hold the sock/panty hose in place.

If you use the CYA you have, then you wouldn't use the Dichlor for shocking. Instead, you would get either unscented bleach or chlorinating liquid to do the shocking. Except for the peak point of shocking (and we'll do that at night and see what the levels are the next morning), you can swim in the pool during most of these additions, waiting at least a little bit -- 15 minutes or so -- for some dilution. We won't be adding very many chemicals, but this depends on your accurate numbers. I believe your Calcium Hardness (CH) is too low since you said you had a PebbleTec pool and that requires calcium just like a plaster/gunite pool -- so yours is way too low. You will need to buy Calcium Chloride which is in products that say things like Calcium Increaser. As for how much, that depends on the accurate CH reading and we don't have that because you are using test strips for that. Again, get a proper test kit FIRST before we do anything else. There is no rush in this. You'll get the test kit from tftestkits.com within days.

If you know there will be a day when your kids won't be using the pool, then the previous night would be a good time to do the shocking. If I assume the CYA is around 40 ppm, then we would shock to 16 ppm FC which going from 2 ppm FC in your 13,000 gallon pool would take about 3 gallons of Clorox Regular unscented bleach (it says 6% Sodium hypochlorite in the ingredients and also says 5.7% Available Chlorine) or you can use an off-brand unscented Ultra bleach if it's a lot cheaper, but it may not be guaranteed to be as potent (i.e. 6%).

Richard

[Andie]

Okay, first I need to get a new test kit. I will go to warehouse pools tomorrow and try to get the tf100 if they do not have that then I will get Taylor 2006. While there should I go ahead and get the calcium increasor (just tell the staff I need to increase my calcium hardness?). Anything else I need to get at supply store as it's hard to go back and forth with the kids.

So, I need not add anything tonight right?

As far as the shock goes. We actually have a shock treatment esp. for saltwater pools...called Saltshock. Is this what I use? Or do I use the bleach?

Okay, I will get the test and then test my water tomorrow and report back with the number. Is that okay???

Thanks again!

~Andrea

[chem geek]

TF-100 is only available on line here, but they ship quickly and I think it's worth it. The Taylor K-2006 will likely not be available in any pool store though the K-2005 might be, but do NOT get that. If you can't find the Taylor K-2006 in a store, then you can buy it online directly from Taylor here or from Leslie's here. But if you end up having to go online, you might as well get the TF-100 since it's more economical. It has a more logical size to the amount of reagents, can measure CYA down to 20 ppm (K-2006 only measures down to 30) and comes with both the accurate FAS-DPD chlorine test as well as a quick and dirty OTO test for quick checks. And no, I have nothing to do with that test kit -- I just think they've done a good job. It's just some folks who are pool users associated with the TroubleFreePools forum. You can also get lots of help there as well -- I look at and respond to multiple forums, but that's the main one along with The Pool Forum, but there are no new registrations on The Pool Forum.

There isn't a rush. Take a deep breath and relax. Your pool is not in bad shape -- it just needs a little tweaking. Order the TF-100 test kit online, wait a few days, then report back. And yes, you'll have to keep adding acid, but you're not adding as much as you used to and we'll take care of that soon. I think turning off your water aeration features (waterfall and bubbler) will help (you can let me know if it does).

Richard