Just finished pool school on new pool / confused about first test for water chemistry

JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#1
Hi, I just tested my water for the very first time after finishing pool school. I am confused by the readings I'm getting, so any help is appreciated!
My kit does not test for Calcium nor Cyanuric acid. We have an inline chlorinator using 3" chlorine tabs.

Here are my readings from my kit:
Chlorine around 0.5 - I've increased my chlorine output from 3 to 5 on the chlorinator dial (range is 1 to 5 on the dial) - do I need to add liquid chlorine or just wait for the tabs??
pH high, color > 7.8, acid demand test is 4 drops, so appears I need to add acid?
Total Alkalinity yielded 7 drops = 70ppm - on my test kid, it says ideal range is 80 to 100ppm but that for trichlor tabs, ideal is 120 to 140ppm?

I'm confused b/c it appears I need to add acid to lower pH, but my TA test shows that I need to increase alkalinity?
Or perhaps I didn't do the tests correctly. :confused: Please help - thanks!!!
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#2
Borax or Baking Soda?

I've read to use Borax to increase pH but to use baking soda to increase total alkalinity? I am a newbie to pool ownership and water chemistry, so please advise. I thought they were the same thing - just wondering whether I can/should use baking soda for both. Thank you!
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#3
How does your water look? I'm assuming if you just finished pool school, it's hopefully still clean and clear.

Our system here is based on understanding the entire range of your pool's chemical levels. Your pool is a giant chemistry set, and everything we test for interacts with everything else - if all the chemicals are in balance and playing nicely together, you get a pool that sparkles like a diamond (a diamond that is more clear sparkles more - water acts very similarly). For this, test strips (we call them guess strips because they're wildly inaccurate), the little partial test kits, and pool store testing (where they'll try to sell you all kinds of things you don't need, and then when you use those chems and it messes up your pool, they're happy to sell you MORE chems to fix what got messed up) aren't good enough - they don't work (no, not even the pool store, where you can get different results with the same test sample!). The best way to understand and take care of your own pool is to have the tests needed to do that. Here, we recommend a TF-100 (TFTestkits.net) or a K-2006C (TFTestkits.net). Both of those kits have all the tests you need to properly care for your pool. You can find them at the links there.

While we're waiting on the test kits, I'll answer your immediate questions as best I can:
pH should be kept in the range of around 7.2-8. Your pH is high, and with new plaster, you'll need muriatic acid to bring it down. The acid you buy should be 31% for the best economy, and you're going to need more than a few jugs to get you through the early months while your plaster cures. Don't bother with dry acid, it's a waste of money, same with "pH Down" - this is basically an overpriced product. You can find Muratic Acid in a number of places, shop around and see who has the best value - try big box stores like WalMart and Home Depot, Lowes, etc.

Since we don't know your CYA levels (that is a test you're missing), we can't say what your chlorine should be. While the pool store may tell you "keep it between 1 and 2", this doesn't take into account CYA, which binds/buffers with the chlorine to protect it from the sun. The more CYA, the less chlorine is available to keep bacteria and algae at bay, so we need to know your CYA level to tell you where your chlorine level should be.

TA - This is a "magic" number. There is no "correct" value for TA - generally, the lower it is (down to a certain point), the slower your pH will rise. For now, I'd say don't try to mess with your TA, it's pretty good at the current level. 70 is pretty good - I maintain mine around 60-70.

Finally, chlorine tablets. I spoke about CYA above. These tablets add CYA to your pool. This is ok if CYA is low (we like to see it around 50-70, especially in sunny Houston), but CYA doesn't really leave the pool - it accumulates in there, and every time you add a new chlorine tab, you're adding even more CYA. We recommend bleach or liquid chlorine (they're the same thing) here because all it adds is a little salt. On the other hand, you have to add it daily during the summer - no dropping in a tablet and forgetting about it. Keep this in mind and consider not using the tablets - they're going to cost you a LOT of money in the long run.

Lastly, some reading!
First, read here: Pool School - ABCs of Pool Water Chemistry
Then, read here: Pool School - Getting Started

Come back with any questions you may have. :)
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#4
Ok, I'm on my way to get the water tested at Leslie's... will post later with the results! I've read through the information and even have a book - just all this new info is a bit overwhelming! Thanks
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#5
Re: Borax or Baking Soda?

This is a great link for you to read at (though it sounds like you are off to a great start already): Pool School - Recommended Pool Chemicals

Your TA is 70, you don't need to raise it - you're in a pretty good spot right there.

You have new plaster, so your pH is going to rise on its own. Once your plaster is cured, if, for some reason you need to raise pH, you can do so by aerating your water - run a waterfall or bubbler, spa jets if you have an attached spa, or turn your return eyeballs so they ripple the surface. These are all free ways to raise your pH. That said, if you still need to raise your pH, you'll want to use borax to avoid too much upwards movement of your awesome 70 TA.

Chlorine tabs reduce pH (they are acidic, which is why you shouldn't put them in the skimmer or pump basket) - if you ditch the tablets, you'll likely find the only time you have to raise pH is if you mess up and add WAY too much muriatic acid while trying to adjust pH down. :)
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#6
Remember, pool stores aren't a great source of testing. That said, whatever you do, DON'T BUY ANYTHING. Bring their recommendations back and we can talk over what you need to do.
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#7
My water looks clean and clear so far. We are about two weeks out from quartz plaster finish, and they completed the acid wash last week. I will purchase a good test kit very soon.

1) I didn't know about chlorine tabs... they just added it to our pool equipment as part of the build - will go get some bleach today. Should I just turn off my chlorinator? Or just turn dial down to lowest setting, which is 1?

2) The pool tech had turned all my eyeballs pointing up! I didn't know that this raises pH - perhaps that's why it keeps going up! How should I keep my jet eyeballs in general?

3) I calculated my gallons to be around 21,800. Should I round up or down for purposes of adding chemicals?

I went to Leslie's, and didn't buy anything! :) Here are my results:

FC = 1
TC = 1
CH = 200
CYA = 50
TA = 110 (I guess I was off - I got 70)
pH = 9
TDS = 900
Pho = 100

So I will get muriatic acid, bleach, borax, and baking soda today. Thanks for all the tips!
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,091
Greenville, SC
#8
1) Just take the tabs out and save them for vacation.

2) Turn them so the water goes clockwise or counter clockwise if you can. BTW, you are going to have rising pH for a while with a new plaster finish.

3) Just leave it at 21,800. Move it up or down if chemistry tells you different.

We don't trust pool store testing so you can skip it all together.
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#9
How often should I test my water with the tendency for rising pHs? Pool tech said I can test weekly, seems like I may need to do it more often.
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#10
In the summer, or in this case when you have new plaster that is going to have a serious effect on your pH, I'd test FC and pH daily. Add acid as needed to keep pH between 7.2 and 7.8. Turn off the chlorinator (remove the tablets if possible) and use bleach to chlorinate - since you're testing daily anyhow, it should be easy to test (with the pump running and after the pump has been running for at least 30 minutes), add bleach, brush and wait 15-30 minutes, then add acid to a different part of the pool and brush that area to make sure it mixes. Be VERY careful when adding both bleach and muriatic acid - also, do NOT store them anywhere near each other. If mixed, a release of chlorine gas or worse can result - this is why you don't add them very close together to the pool.
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#11
Ok, will test daily then and turn off the chlorinator.

How long after adding chemicals (chlorine, acid) should we wait to swim? Is it a few hours or should we wait until the next day after testing again?

Our spring break is next week and my kiddos are hoping to be able to finally swim for the first time! :)
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#13
As long as the pH is between 7.2-8.0, and chlorine is below SLAM levels (for now, we'll ASSume your CYA is 50, though this is the one the store gets wrong the most), which according to the chart (Pool School - Chlorine / CYA Chart) is 20, and you can see the bottom of the pool (for safety), it's safe to swim. :)

If you're worried about adding chemicals and then swimming, I add chems right in front of a return (so the return can "blow" it into the pool), then brush vigorously around the bottom where I added the chems. I then have the little ones wait about 15 minutes or so with the pump running before letting them in.
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#14
Is there a limit to how much acid I should add at a time? According to Pool Math, I need to add 74 oz of acid to lower my pH. Can I add that all at once?
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#15
That seems like a lot of acid, but it is possible. Checking your numbers in PoolMath, that's correct. But that's making two assumptions: 1. That your pool volume is correct. 2. That 9 is a "good" number, and with pool stores, I wouldn't count on it.

So let's approach it this way. We know your pool's pH is at least 8 based on your own testing (and likely higher). Let's start with 30oz - that's enough to go from 8 to somewhere near 7.5 or so based on your estimated volume - not enough to overshoot. Pour it very slowly, with the pump running, in front of a water return (the little jets in the wall where the pump water re-enters the pool). Once poured, give the area around which you poured the acid a good brushing to stir up the water, then wait about 15 minutes and retest pH again using your test kit. If it's still reading above 8, let's put in another 20oz and do the same brush/wait again. If you're still showing 8 or higher, do it once more. That will bring you up to about 70oz added and we can re-evaluate where we sit then. I just don't want you to put too much in at once and end up with a pool that is too acidic.

Edit - I forgot to ask earlier - this is a new pool. Did you get a warranty card or statement from the builder? If so, what does that warranty require you to do? It's very important to follow the warranty instructions in case something goes wrong with the plaster and you need to make a claim.
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#16
Ok will try that. I didn't get a warranty card except what's stated on our contract. I'll ask if there are other instructions, but we followed everything their pool techs told us to during the start-up process. We had pool school Monday so feel like we're on our own now.
 

triptyx

TFP Guide
Apr 12, 2016
1,485
Tucson, AZ
#17
Ok, no problem. Some builders have requirements as to how you have to care for the pool (certain chemical levels, testing, etc), check your contract and make sure. :)
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
36,684
Tallahassee, FL
#18
JuYuHu, I just wanted to jump in and say you are doing a good job asking questions and making sure you understand what you are doing!

Triptyx is doing an awesome job guiding you (THANKS Trip!!!!). Listen to him and do what he tells you to. That includes reading the links he has give you so you can understand the WHYS of what you are doing.

:hug: and let those kids swim!!!!!

Kim:kim:
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#19
Yes I appreciate all the tips I'm getting! Very helpful. I've been spending a lot of time reading and researching. However, when I actually ran my first test today, all of a sudden I felt clueless! LOL. I have learned more today from this forum than from all the research this past week, and that includes reading a pool maintenance book!!
 
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JuYuHu

Well-known member
Mar 7, 2017
97
Houston, TX
#20
Ok, so I purchased liquid chlorine 10% (approx. $5/gallon) and muriatic acid ($13 for 2 gallons) from Home Depot! After adding chemicals two times, waiting about 30 min in between, I finally achieved appropriate levels!

Cl - just above 3ppm
pH - about 7.6
TA - 70ppm

This was done with my start up test kit, as compared to the color blocks. Will test again tomorrow. I feel like this testing may become a bit OCD-ish... :p hopefully I will get a good feel for the swings in my pool soon!