New pool owner, trying to get my chemicals balanced

[mitchryan912]

Hey everyone,

I'm a new homeowner and am new to maintaining a pool. I've recently taken 2 semesters of 100-level college chemistry and a 300-level organic chemistry, so I'm familiar with a lot of terminology and reactions going on in my pool. However, the previous owners of this home are my in-laws, so I'm getting some advice which I'm not 100% sure is correct, mainly that my father-in-law never did anything with adjusting alkalinity nor added any stabilizers.

ANyway, I've been going to a local pool store to get my water tested, and my first test read:

0 stabilizer
0 chlorine (it was burning off 1 gallon within 24 hours!)
7.8 pH
65 TA
120 CH

I followed their advice and added these chemicals, in this order:

.75 gallon of muriatic acid (31.25%)
3 gallons of 12.5% hypochlorite (this now seems high, but maybe ok?)
15 lbs of sodium bicarbonate
15 lbs of calcium carbonate (I have a vinyl liner, so I think this is unnecessary to add in the future)
5 lbs of cyanuric acid stabilizer

This treatment seems to do wonders for my pool, but we've since had a lot of heavy storms (a few tornados have blown through here in the midwest) and my levels are out of whack again. I did a chlorine shock (2.5 gallons) between storms and that held up for about 9 days until this past weekend. Now I'm trying to get things back in order, but I'm hearing conflicting advice at the store I've been going to (notably about shocking vs adding acid as the first step.)

That's it for now, but I'm sure I'll have follow up posts/questions in the future.

[mitchryan912]

As a follow up, 3 days after the treatment I described, my results ended up as follows:

15ppm stabilizer
1.0ppm chlorine
7.2 pH
120 TA
190 CH

A few days later, we believed there was an odd smell from the pool, so I was told to shock the pool with 4 gallons of chlorine (I only had about 2.5) to deal with the potential smell (it turned out something happened to our towels, which is where the smell came from.)5 days later, I had my pool checked again and my TA and pH went up (150 and 7.6), while my stabilizer disappeared (0 ppm.)

I then treated the pool with 2 quarts of muriatic acid, but we had a huge rainstorm which caused me to drain the pool down a few inches (about 1200 gallons, if I'm calculating it correctly.) This is where someone new to the pool store started running tests for me, so I'm not 100% sure if these numbers are right:

0 stabilizer
0.5 chlorine
7.6 pH
100 TA
160 CH

Is that normal for TA to go down while pH stays the same? I'm currently in need of lowering pH while keeping TA the same, but I'm not sure how to accomplish this?

[mitchryan912]

I am now a subscriber. Thanks!

[PoolDoc]

1. Get a K2006, so you can test it yourself. It actually sounds like you may be one of the very few who have found a pool store that tests water accurately . . . but the only way to know is to DIY. http://pool9.net/tk/ (Please ignore the booklet and wheel in the kit, at least till this fall!).

2. Transported samples of pool water may not have the same TA or pH as the same water in the pool, due to heating / cooling / aeration. See http://pool9.net/alk-step/ for an (indirect) explanation. Basically, if you want an accurate test of pH you must collect the sample in a bottle leaving ZERO head space (ie, cap it underwater) and (b) keep the sample temperature stable.

3. Depending on how they tested, the testing error for CYA levels at the low end can range from plus-minus 10 ppm (K2006 with experienced user) to plus-minus 50 ppm (eye-balled test strips). I don't know your pool volume, so I don't know what your CYA should have been after you added 5# . On a 30k gal pool, 5# would add 20 ppm. BUT, it dissolves slowly. People often 'lose' it backwashing before it dissolves. This most often happens when your pump is timer operated.

Next time, dissolve it in a sock in the skimmer OR use dichlor (9 ppm CYA for ever 10 ppm FC). (I know that doesn't add up; not going to explain while I'm behind on new users.)

. . . membership updated.

[Watermom]

Maybe I'm wrong but when I read your posts I got the idea that testing and making chemistry adjustments were things that were both happening periodically but not regularly. If that is the case, that isn't going to work. You have to tend it on a regular consistent basis like daily for now. After you learn how your pool behaves, you may be able to go a day or so between testing and adjusting but not now.

Welcome to the Pool Forum and thanks for the subscription!

[mitchryan912]

1. Get a K2006, so you can test it yourself. It actually sounds like you may be one of the very few who have found a pool store that tests water accurately . . . but the only way to know is to DIY. http://pool9.net/tk/ (Please ignore the booklet and wheel in the kit, at least till this fall!).

Working on ordering one, as NO ONE in town carries Taylor kits (one I don't frequent can get the 2006... for $99!) Yeah, I think the guy who did my first couple tests knows what he's doing, but then I went to the sales counter and was told to change the order of operations:

Test guy:
1. Shock the pool (3 gals chlorine)
2. Raise TA (15 lbs baking soda)
3. Raise CH (5 lbs CaCL2, 3 doses @ 8 hour intervals)
4. Adjust pH (1 qt muriatic acid)
5. Stabilizer (5 lbs CYA)

The sales guy's suggestion:
1. Adjust pH (3 qts muriatic acid, and I already had a gallon at home, so he didn't make an additional sale here.)
2. Shock the pool (3 gals chlorine)
3. Raise TA (15 lbs baking soda, all at once)
4. Raise CH (5 lbs CaCL2, 3 doses @ 8 hour intervals)
5. Stabilizer (5 lbs CYA)

I'm not sure what's the preferred order of operations here, as I've read conflicting things about what works? All I do know is that the store has a sheet they fill out when testing, and that the sheet says to go in the order of each item (maybe I'll scan it so you can see what I'm seeing.)

2. Transported samples of pool water may not have the same TA or pH as the same water in the pool, due to heating / cooling / aeration. See http://pool9.net/alk-step/ for an (indirect) explanation. Basically, if you want an accurate test of pH you must collect the sample in a bottle leaving ZERO head space (ie, cap it underwater) and (b) keep the sample temperature stable.

It's a 30 minute drive to this particular pool store, but I often am heading straight there after I take a sample.

3. Depending on how they tested, the testing error for CYA levels at the low end can range from plus-minus 10 ppm (K2006 with experienced user) to plus-minus 50 ppm (eye-balled test strips). I don't know your pool volume, so I don't know what your CYA should have been after you added 5# . On a 30k gal pool, 5# would add 20 ppm. BUT, it dissolves slowly. People often 'lose' it backwashing before it dissolves. This most often happens when your pump is timer operated.

I think I've gotten myself frustrated because I just bought some AquaChek yellow test strips, and was told these should get me in the ballpark but wouldn't be totally accurate. My test strip shows pH 6.8 while my cheap pH test (with phenol red) shows pH 7.6. Granted this is after adding acid and chlorine over the past 24 hours, so I don't expect either of them to be accurate, but was hoping for them being close to each other.

I have a 26,000 gallon pool, and was told to not backwash for 3 days after adding CYA. I've been backwashing, rinsing, and sending out extra water to waste (lots of rain lately) before I do any major adjustments, so I don't lose anything I've just added and so that my skimmer actually skims.

Also, I don't have a timer, so the pump runs 24/7. I don't know if this is a bad thing for anything outside our electric bill? I don't have a way of changing it to add a timer unless I revamp ALL my home's electrical paneling (I'm a former electrician, and the main panel is ancient and wired WAY out of code, much less the "sub panel" the pool pump is wired to.)

Next time, dissolve it in a sock in the skimmer OR use dichlor (9 ppm CYA for ever 10 ppm FC). (I know that doesn't add up; not going to explain while I'm behind on new users.)

. . . membership updated.

Thanks, I'll give that a shot next time.

[mitchryan912]

Maybe I'm wrong but when I read your posts I got the idea that testing and making chemistry adjustments were things that were both happening periodically but not regularly. If that is the case, that isn't going to work. You have to tend it on a regular consistent basis like daily for now. After you learn how your pool behaves, you may be able to go a day or so between testing and adjusting but not now.

Welcome to the Pool Forum and thanks for the subscription!

Thanks! Yes, I've been checking it was a cheapo $10 OT/PR test kit every day, but since I'm new to understanding how much of each chemical affects the system (notably high chlorine & pH), I've been doing my own tests PLUS making trips to my pool store every 3-5 days to have them do a full workup. All the gas plus unneeded chemicals adds up to making a K2006 worthwhile, so I'll be getting one of those to check levels daily.

That said, is there a sticky for intervals between adding a chemical and when it's either A) safe to swim or B) your test kit will be accurate in its measurement? My father-in-law used to shut the pool down for the day whenever he'd add anything, but now that we own the house (and have kids that want to use it!), we don't really want to have down days unless it's a rainy or cold day.

[Watermom]

Trust your OTO/Phenol Red kit over the test strips. Order the Taylor K2006 or 2006C (better buy) from the link that Ben provided above as soon as you can. It will make things much easier.

As long as you have a pH reading between 7-8 and some chlorine in there, you can swim. We'll need some numbers that the K2006 can provide to better be able to advise you on needed levels. Chlorine is dependent on CYA readings. Take a look at the chart at this link for more about this relationship:> http://pool9.net/cl-cya/

With your OTO kit, if your chlorine is over 5ppm, you can use this chart to interpret off the scale colors:> http://pool9.net/oto-chart/
Your pH will be inaccurate if your chlorine is over 5ppm (or over 10ppm with the Taylor kit). So, if you have high chlorine, you can dilute your test sample 50/50 with pool water and distilled water and then test pH with that mixture.

[PoolDoc]

Trust the cheapo OTO/phenol red drops kit. Ditch the AquaCheck strips.

=> *ORDER* the K2006; we've still never heard of a pool store carrying these. (Why would they stock a kit that will tend to put them out of business.)

=> Any pool store that tells you to add calcium to a vinyl pool is not to be trusted: they are selling you chemicals that are worse than useless in your pool, since they have NO benefit, but can cause problems.

=> If your pH is between 7 and 8 --AND-- your chlorine is greater than 1.0 OR 10% of the CYA level, whichever is higher --AND-- you haven't added any funky chemicals like foamy algaecides, mustard algae treatments or non-chlorine shock . . . it should be fine.

=> Wait time after adding chemicals is often 5 minutes, but it depends on your pool, where you added them, what you added, and how the pool circulates. If you want a safe number that's pretty much arbitrary, but almost certain to be safe, then go with "1 hour after chemical additions WITH THE PUMP ON and CIRCULATING".

[PoolDoc]

Ugh. Another simul-post!