1st time user of TF-100 kit and Pool Math

[kingadriann]

I tested my chlorinated (20,000 gallons) pool, and here is the result from Pool Math app. I have 0 CC. I bought 5 gallons of Suncoast liquid chlorine with 10% strength, and Transchem Muriatic acid with 31.45% strength.

I drained my pool to 1/4 from the top, refilled with water from the hose.

So what should I do first? Drain some more before adding any liquid? I have super strong sun in the afternoon.

Please advise, thank you so much.

Pool 27822
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Build Type: Plaster
Volume: 20000 gallons
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Latest Test Result Summary:
FC: 3.0 (8 minutes ago)
CC: 0.0 (8 minutes ago)
pH: 8.3 (8 minutes ago)
TA: 170 (8 minutes ago)
CYA: 120 (8 minutes ago)

 

[mknauss]

How did you test to get a CYA of 120?
Do the Extended Test. CYA - Cyanuric Acid Test
You likely need to drain 3/4 of your pool volume, more or less, depending on your Extended CYA test result.

Draining has risks. In your area of Katy, do you have a shallow water table?

 

[jeffchap]

Just to be clear, 0 CC is good. Anything over 0.5 indicates that something is growing in your pool.

FC is what indicates the level of free chlorine available to sanitize your pool. It should be at least 7.5% of whatever your CYA is, and I prefer to keep mine around 10% for a little added cushion.

This is why mknauss is saying that you need to drain and refill -- your CYA is much higher than preferred. For a manually chlorinated pool, you want to keep it around 30 ppm. This would give you a target FC of 3.

But with your CYA at 120 (or possibly higher, since the test only goes to 100), your target FC would be 10 ppm or more. It takes a lot of chlorine to get there. So the first step is to lower your CYA to a manageable range.

 

[kingadriann]

Hi:

I did the extended CYA test, followed the instruction that comes with the TF-100 kit exactly. I went outside where it's real bright, my back against the sun, slowly poured the pool water / R-0013 combo to the view tube, till I no longer see the black dot.

I will drain my pool again tonight, and hopefully it will lower down the CYA before I do anything else.

I will update when I see progress...

Thank you very much for the advice.

Have a safe Memorial Day weekend!

 

[kingadriann]

Good morning, I passed by a Pinch a Penny store and decided to bring in my pool water sample to be tested. Here is the result.

Their recommendation is to pour 3 gallons of muriatic acid, 1 gallon per 8 hour, and then retest.

Does this sound right?

Thank you

 

[jeffchap]

That's waaaay too much acid. Pool Math says that would lower your pH by 2.3. One gallon would lower it by .8 to 7.2, which would be perfect.

Avoid that place! No one with any knowledge of pool maintenance would ever make a suggestion like that.

 

[kingadriann]

Ok I will do 2 gallons only, 8 hours apart. Thanks, that’s why I seek advice here
Have a safe Memorial Day weekend.

 

[duraleigh]

A couple of axioms at TFP is "Trust your own Testing" and "Stay out of the pool store". We all want reassurance, especially when new to testing but the pool store is a bad place to get it

 

[duraleigh]

Re-read what Jeffchap said.....one gallon of acid- not 2

 

[kingadriann]

Ah ok misread, my bad. One gallon it is tonight. When they say dilute it with water, is it pool water or tap water from the hose?

 

[Wobblerlorri]

You can dilute it with either. Just remember to always add acid to water -- no splashback that way.

 

[mknauss]

Ah ok misread, my bad. One gallon it is tonight. When they say dilute it with water, is it pool water or tap water from the hose?

No reason to dilute the acid. Add it slowly at a return with pump running. Pencil size stream. Brush the area well afterwards.

 

[jeffchap]

I don't dilute mine. I just lower the jug into the water and pou.

 

[kingadriann]

Oh that sounds less hassle, I will pour slowly near return next time. Add water first, then add acid. Got it, thank you.

 

[kingadriann]

I tested my water this morning using the TF-100.

Here is the result

PH - 7.2
TA - 120
FC - 1
CC - 0
TC - 1
CYA - 100

Pool Math tells me to add 2 gallons of liquid chlorine. I will add liquid chlorine (10%) strength that I bought at pool store tonight and test again tomorrow. I will get 3 days of rain in the forecast starting tomorrow, and I will retest the CYA again hopefully it brings it down. Any recommendation?

Thank you very much

 

[duraleigh]

I will get 3 days of rain in the forecast starting tomorrow, and I will retest the CYA again hopefully it brings it down.

Rainwater will have no affect on CYA (unless your pool overflows).

I forgot, what does your water look like currently?

 

[kingadriann]

I just took this picture.

Algae by the ledge right under the waterfall but I will pour 2 gallon maybe more to hopefully kill all the remaining algae.

I have turned the dial to zero on my chlorinator, took out all pucks from skimmer and floaters before I pour muriatic acid yesterday.

Thanks

 

[duraleigh]

Brush that algae up into the pool water so the chlorine can kill it.

You should be doing measured applications of chlorine, not "two gallon maybe more".

I would suggest you get you
FC up to around 26 ppm and brush and vacuum your pool.

You are close to a clear pool but you need more chlorine.

 

[kingadriann]

When I entered 26 as the "target free chlorine" and 1 as my current free chlorine, it told me to add 5 gallons. Does this sound right?

Thank you

 

[duraleigh]

5 gallons of what? 10%? Tell us what you are planning to use for FC.