Complete newbie, cyanuric acid/salt questions

[Saltyhog]

Brand new pool (3 months old) and first time pool owner. I've just found this site and I'm going to implement the methods outlined here. I just have a couple of stupid questions to start with.

My cyanuric acid level is only 40 (bad advice from the never to be used again pool store) and I intend to raise to to approx. 75. What's the best way to put the cyanuric acid in the pool? Put it in the skimmers, broadcast it in the pool?

TFP recommends to run salt 200-400 above the manufacturers recommendation. My salt cell recommends 3600 (which is where I run it presently) Do I really need to run it 3800-4000? Will that affect my warranty if I do?

Current parameters

alkalinity 80
pH 7.6
salinity 3600
total chlorine 3
calcium?

Currently testing alkalinity and free chlorine with Hanna photometers, testing pH with a Hanna pH meter calibrated with 7.01 and 10.01 standards weekly. Have the recommended Lamotte test kit ordered.

 

[mknauss]

Welcome to the forum!

At this time of year no real reason to raise your CYA at this time. You will be using less and less FC per day as the sun angle drops towards winter. In fact, the SWCG will stop at about 60F (I actually turn mine off around 65F water temp and use bleach the rest of the winter). So no need to add CYA at this time.

The salt is OK too - I have the same SWCG and run mine at about 3100 ppm. It will make chlorine in a very wide range. No warranty issues.

I would suggest considering getting a drop based test kit versus the Lamotte. The TF100 is the best value.

Take care.

 

[Saltyhog]

Thanks Marty! I'm having to add muriatic acid pretty often (about a gallon a week total) and was hoping getting the CYA up would improve my pH stability. Should I just wait till spring and just continue to add MA?

 

[mknauss]

CYA will do nothing to stabilize your pH.

If this is a new plaster pool, you will be dealing with rising pH for a year or so. Otherwise, once your TA and pH find their equilibrium, your pH rise should slow.

Just noticed - FYI - your SWCG is really undersized. In the summer you will either be running your pump 24/7 with your SWCG set at 100% or supplementing with liquid chlorine on a daily basis.

Take care.

 

[Saltyhog]

Thank you again. I guess I misunderstood the article on balance in the Pool School section. It said something about CYA being too low leading to high acid demand. I figured there would be some leaching from the new plaster that would raise pH, just didn't think about it being this significant.

Just noticed - FYI - your SWCG is really undersized. In the summer you will either be running your pump 24/7 with your SWCG set at 100% or supplementing with liquid chlorine on a daily basis.

Take care.

That is a bit disturbing. I wonder if the contractor's calculation of volume is wrong. My pool temp has been 87-91 degrees for the last two months and I'm running my pumps 12 hours a day with my SWCG set at 20% and my chlorine levels have been very steady.

If that happens next summer I'll have to be looking in to a bigger SWCG.

 

[mknauss]

I would check your pool volume. Try using PoolMath to estimate volume.
You can also use your acid adds to fine tune your pool volume. Test your pH, add XX amount of acid to lower to XX pH based on pool math with your 40K volume. Circulate the water for 30 minutes and test your pH again. See if you get the pH that you used for Target in PoolMath. If not, adjust volume until your numbers match.

Take care.

 

[JeanZ1]

I also have the LaMotte titration (drop) kit and am very happy with it. I've used their other chemistries before and very solid results. I only wish I had a pH meter, would make life so much simpler!

 

[Saltyhog]

I would check your pool volume. Try using PoolMath to estimate volume.
You can also use your acid adds to fine tune your pool volume. Test your pH, add XX amount of acid to lower to XX pH based on pool math with your 40K volume. Circulate the water for 30 minutes and test your pH again. See if you get the pH that you used for Target in PoolMath. If not, adjust volume until your numbers match.

Take care.

Great idea. It did take less salt than calculated on start up. It's a free form pool that varies from over 8' deep to 2' deep ...plus the spa so I've struggled with trying to estimate the rectangular equivalent and average depth.

Poolvid - YouTube

 

[Saltyhog]

I would check your pool volume. Try using PoolMath.
You can also use your acid adds to fine tune your pool volume. Test your pH, add XX amount of acid to lower to XX pH based on pool math with your 40K volume. Circulate the water for 30 minutes and test your pH again. See if you get the pH that you used for Target in PoolMath. If not, adjust volume until your numbers match.

Take care.

Check to make sure I did it right. My pH was 7.71 today and I added 56 oz of muriatic acid(the amount recommended to lower it to 7.3 for 40k gallons) . 1 hour later I rechecked pH and it had dropped to 7.13. I replaced the goal I had originally put (7.3) with the 7.13 and adjusted the volume till the amount of acid recommended was right at 56 oz. It was about 25K gallons. Is that correct?

If so they way over calculated the volume. You would think their design program would give them a more accurate number than that.

 

[mknauss]

That is correct. Start using 25K for your volume. I would suggest you do the above the next few times you add acid to check but it should be close if your pH testing method is accurate and repeatable.

Your SWCG output will be better, but I suspect you will need to run it nearly 16 hours a day next summer.

Take care.