Have test results... what do I address first??

[tfpc]

I'm a new pool owner as of last week. The pool is a SWG pool, and I've been reading up on the forum regarding the ideal chemistry makeup for those types of pools, in particular a CYA level of 70-80 and TA of 60-80. Both of these levels were way off the first time I ran the tests, and at the time all I had were AquaCheck pool and spa test strips. The color coding was showing a PH of over 8.4 combined with TA of over 240, and a Stabilizer level of 0. So, I ordered the Taylor K-2006 kit for more accurate measurements, ordered 25 pounds of CYA, and picked up some 31.45% Muriatic acid.

Both the Taylor test kit and the CYA were going to take a couple of days to arrive, so I went ahead with 1 gallon of the Muriatric acid. The "Pool Calculator" indicated I would need 247oz to bring the PH down to 7.0, which I understand is the approach to bring down the TA levels, but I stayed with 1 gallon because I wanted to ease into it. The next day I got the Taylor test kit and the PH was 7.2, and I'm not really sure why the pool calculator was so far off (i.e. could be inaccurate test strip results, user error trying to decipher the color codes). Using the Taylor kit, the TA is 225, and CYA is zero.

My dilemma is that I think I need to increase the CYA and decrease the TA, but not 100% sure what to do first. The pool calculator says I need 17.8 pounds of CYA, but it also says that much CYA will lower the PH by 1.5. I've also read that adding CYA will contribute to a higher TA. Should I ease into the CYA 5 pounds at time to address that problem first, and then focus on getting the TA down as much as I can before the Minnesota season runs out? Any other advice? Any safety concerns for getting my kids in the pool this weekend?

FC - 4
CC or TC - Haven't Tested
pH - 7.4
TA - 225
CH - Haven't Tested
CYA - 0
Salt - 2800

 

[jblizzle]

Welcome to TFP!!!

Forget about the TA ... it is the last thing to even worry about after everything else is in line and you are bored with nothing else to do. Just keep the pH in the 7s.

Certainly start building up the CYA level by putting it in a sock and hanging in front of a return jet or in your skimmer.

CYA will not raise the TA and the impact on pH is usually pretty negligible.
I would target a CYA of 30-40ppm to start, then do the Overnight Chlorine Loss Test to make sure there is nothing lurking in the water.
Then bump the CYA higher if there is no need for the SLAM process.
Use bleach to keep the FC in range for your CYA according to the [FC/CYA][/FC/CYA]. Until the SWG is dialed in.

FYI, use PoolMath and not the old pool calculator that is out of date.

 

[aussieta]

i also reccommend sneaking up on the cya level
as you had such a dramatic drop in ph your pool may be much smaller than you think

 

[lightmaster]

Your salts also pretty low for your SWG, so you'll want to raise your salt up to 3200 ppm.

PoolMath says that 107oz by weight of granular stabilizer will raise your CYA to 27ppm. Try to measure out 107oz by weight as accurately as you can and pour that into a sock (with no holes in it, lol) and hang it in front of your return. You can massage the sock to speed up dissolving it. Give it a day or 2 to fully dissolve and then test your CYA. If a properly done test (directions are linked in my signature) says you have 30ppm CYA, then you know your estimate of 26.7k gallons is fairly accurate. Also, while your dissolving the CYA, go ahead and target FC for a CYA of 30, which means target 5-6 ppm FC.

- - - Updated - - -

Forgot to mention, being that you have a vinyl pool, don't ever add calcium to your pool. Calcium is only important to other surface types because low levels will leech calcium out of the stone, plaster, etc. High levels however, will cause scaling on all pool types, so you can keep yours as low as you like and don't need to waste your money. Pool $tores love to sell calcium to vinyl pool owners because while low levels won't hurt vinyl, its a easy sale to make them more money.

 

[AftonJeeper]

Any other advice? Any safety concerns for getting my kids in the pool this weekend?

Congrats on the new house and pool! From time to time you will need to add chlorine to your pool because the SWG cannot always produce enough FC to meet the needs of the pool. Best place I've found so far to buy chlorine is Menards, they have 12.5% "pool shock" as they call it for $3.99 or less everyday and it is fresh.

Wait until your water temp drops below 60 to close your pool, algae grows much slower at lower temps. I still use a pool company to close my pool but I won't let them add any chemicals. More on closing a pool here.

Watch your pH and FC daily until you get an idea what the pool needs. Many here now test every other or every third day or longer.

The pool is safe to swim in when chlorine is between shock level and minimum for your CYA, pH is between 7.2 and 7.8 and you can see the bottom.