New pool test results & questions

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CheyDee

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LifeTime Supporter
Oct 8, 2007
27
Tucson, AZ
Hi everyone!

I posted last year with a question regarding handrails for an existing pool in a house we almost purchased. We wound up not buying that house after all. Instead, we went for a new build and a new pool.

The pool is finished and the water is in. The PB's rep who came over to "educate" us on 4/1 added three pucks of trichlor, 3-inches in diameter x 1-inch thick, and 1/2 gal of muriatic acid. I was so overwhelmed that I have no idea what our numbers had been and did not think to write them down. I only remember that the ph was off the top end of the chart. He told us to pump for 24 hours, then cut back the pumping to 6 hours per night, recheck the chemicals in one week and add whatever was needed then, based upon whatever numbers came up in the tests. Dummy that I am, I listened.

....Okay.... You could all stop shaking your heads now...

I retested the water on 4/7, Of course the FC, TC, and CC were zero, the ph was at least 8, the TA was 120 and the CH was 350. I did not test for CYA, because I misunderstood the instructions and thought I was missing a piece from the test kit. All we had to treat the water with are those trichlor pucks and the remaining 1/2 gal. of muriatic acid. So... I added another 3 trichlor pucks and the rest of the muriatic acid.

I finally found an old post somewhere, which referred me to Taylor's website. They gave a very nice diagram with instructions on how to do the CYA test. Duh!

Okay... so, if I did everything correctly, this evening's numbers are:

FC 1.0
TC 2
CC 1.0
ph 8
TA 90
CH 350
CYA 60
H2O temp 70F

I plugged the #'s into The Pool Calculator and, if I am doing this correctly, I should be adding 66 oz. of 6% bleach and 13 oz. of 31.45% muriatic acid? I just found out, however, that 1-1/2 of the trichlor pucks that we put in two days ago have not yet dissolved. I also found out that DH forgot to change the timer after adding the chemicals on 4/1 and we have only been pumping for 6 hours/night. Is that why the trichlor did not dissolve?

Since there is still trichlor waiting to dissolve, should I add only the muriatic acid tonight and then pump all night?

DH is on his way as I type this to pick up muriatic acid and bleach. (He just called. He can only get 14% muriatic acid. Probably just to confuse me! LOL! I hope there is a conversion for that somewhere, since The Pool Calculator mentions the higher concentration.)

Thank you for any thoughts.

Edited to add: The bleach he bought is 10%.

--------------------------------------------------------------------------------

Just built: 12x30 IG gunite/plaster play pool w/ in floor cleaning heads & auto water leveler, (10,584 gal), two Jandy Stealth SHPF 1.0 hp pumps, Jandy CL460 cartridge filter, Taylor K-2005 test kit. (I think that is everything!)
 
There are two key things you need to get under control, FC and PH.

You want to keep FC at 5 or higher, preferably more like 7, at all times. That means adding chlorine daily. I suggest switching to bleach and adding it once a day in the evening. Right now that means adding 79 oz of 10% bleach.

You need to keep the PH below 8 at all times. That means lowering the PH down to 7.2 any time it gets to 7.8 or higher. Right now that means 26 oz of muriatic acid.

Both FC and PH will need to be checked daily to start. Later, when you are more familiar with the pool you may be able to spread that out more, but for now you need to keep on top of things.

With CYA already at 60 you want to stop using the trichlor tablets. If there are a couple already in the skimmer you can leave them there, but don't add any more.

Your CC level is a bit high. If you get your FC level up to where it needs to be I think the CC will go away. If the CC isn't down to 0.5 in two or three days you will need to shock the pool. Probably it won't come to that.
 
Thank you so much for your prompt reply. It brings up more questions though. (Sorry!)

I thought I read someplace that FC should be between 1.0 and 3.0. That is incorrect?

What did you calculate to get 26 oz of 14% muriatic acid and 79 ounces of 10% bleach?

Also, I thought TA should be between 100-140? My results are 90. This will self adjust if everything else is corrected?

I trust your calculations; I just want to learn how to do them myself :)
 
CheyDee said:
Thank you so much for your prompt reply. It brings up more questions though. (Sorry!)

I thought I read someplace that FC should be between 1.0 and 3.0. That is incorrect?

What did you calculate to get 26 oz of 14% muriatic acid and 79 ounces of 10% bleach?

Also, I thought TA should be between 100-140? My results are 90. This will self adjust if everything else is corrected?

I trust your calculations; I just want to learn how to do them myself :)
Click to expand...

FC is dependent upon CYA levels....the higher the CYA, the higher the FC required for proper sanitation. See Bens Best Guess Guide for details. If the pucks are in the skimmer and you are adding the bleach thru the skimmer, make sure you take out the pucks prior to pouring in the bleach. Can't remember if your sig showed inline delivery or thru skimmer. Also, you originally had TA of 120, and now down to 90. That's quite a change in less than a week. Maybe the big boys can explain that.

Good luck, and keep your head. It gets easier.
 
I looked at Ben's Best Guess Guide the other day and it made absolutely no sense to me. :oops: I looked at it again tonight and it did. Now I'm scared! LOL!

Thank you for steering me in the right direction and for the kind words.
 
I use my Pool Calculator, see the link in my signature, to figure out amounts.

CYA "buffers" chlorine, reducing the amount that is available to sanitize your pool, while holding the remainder is reserve in case the active chlorine goes away. That helps protect the chlorine from sunlight, which deactivates chlorine fiarly quickly without any CYA, but it also means that you need to use higher FC levels to get the same effective sanitizer level. The traditional 1-3 recommendation is assuming very low CYA levels.

The muriatic acid measurement was assuming 31.45% strength.

You have a brand new plaster pool, so PH, TA, and CH will all be rising quickly for the first several weeks and slowly for up to a year after that. The acid you need to add will lower the TA but then the plaster curing will raise it back up again. Don't worry about adjusting TA on it's own until at least a month after the paster was applied. After a month the TA level you want depends on what form of chlorine you are using. For bleach a good TA level is 70-90.
 
I must have a forum setting incorrect, because I do not see a signature at all for you. I do have your pool calculator bookmarked though, from a previous visit. (Thank you!!!) I didn't realize I should put "7" under the goal, because above it was the word "gallons". Now it makes more sense to me. Even though I didn't "get it" last night, I went by what you told me and put in the 79 gallons.

How do I convert 31% muriatic acid to 14%, since that is what we were able to get from the hardware store? I only put in the 26 oz of muriatic acid last night.

I can't wait to do this all again tonight. :roll:

Thank you for your continued patience.


Edited to add: Hey!! After I just posted your signature appeared. I am POSITIVE it was not there before.
 
CheyDee, Welcome to TFP!

Sounds like you are getting things under control. We have wonderful gurus here :)

What? A new pool build? :shock: And where are our pix? :shock: :-D

Seriously, when you have some time, let us see :)

Happy swimming.....
 

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Tonight's numbers and treatment:

I only tested tonight for chlorine, pH and CYA. I got:

FC: 2
TC: 5
CC: 3
pH: 8.0
CYA: 52 (approx.)
Temp: 70F

If I used The Pool Calculator and did the math correctly, I should add:

66 oz. of 10% bleach (to get the pH up to 7) and
72.6 oz. of 14% muriatic acid (33 oz. of 31.45% x 2.2)

Is this correct? (Someone please say "yes", even if it is a lie! :wink: )
 
There are indeed a bunch of wonderful gurus here. Many of the conversations at this point are way over my head. I hope to understand a bit more as time goes on.

Unfortunately, I did not take any pics until the gunite stage. It is a small, raw backyard too, since it is new construction, so there isn't much to see. The few pics I have are at:

http://www.kodakgallery.com/I.jsp?c=73eenml.a20vh4vt&x=1&y=srj5wt&localeid=en_US

Thank you so much for the warm welcome!
 
Yeah!! Thank you, thank you, thank you!!!

The pool looks crystal clear and beautiful. If it wasn't 70 degrees, I would be very tempted to jump in.

Why would the CC be rising? There is nothing visible like algae.
 
CC is formed when chlorine starts to break down some organic compound in the water but there isn't enough chlorine to finish the job. This is very common when fighting algae or opening a pool after it has been closed for a long time but fairly unusual on a brand new pool. There is some chance there was some algae that was just getting started but didn't get to the point where you could see it yet. What ever it is, if CC isn't headed down tomorrow you should shock to pool to be sure you get rid of it, what ever it is.
 
Oh dear. I see another funky math calculation coming. *sigh*

I live in the desert. It has been windy the past couple of days and there has been a bit dust blowing around. Could that be what the chlorine is fighting?

If my numbers turned out to be exactly the same tomorrow.... How much chlorine would I need to shock the pool?

If I use Ben's Best Guess chart for this... I would want to bring the FC up to 15 ppm? If so, then I would need to add 171 oz. of 10% bleach? Would I still treat the pH if that remains high?

I think I need to buy a gas mask!
 
You need to keep up with the PH drift no matter what else happens. That can get a little tricky if your FC is above 10 for very long, since the PH test starts to get a little inaccurate around there. Hopefully you are starting to get a sense of how much acid you need to add each day and can guess at the amount if the FC level is too high to measure PH.

With CYA of 52 shock level is around 15-17, so your chlorine math looks right.
 
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