Another testing question

Sep 20, 2015
55
QLD Australia
I've been slowly raising my FC since using the TFP method from about 2.5 to 6. I've also been maintaining TA of 80 and pH of 7.5. I was a bit hesitant to raise the FC that high thinking the pool water would taste yuck and sting our eyes. But nope. :)

The pool clarity has never been better. I mean, there are virtually no visible particles floating in the water even with the pool LEDs on at night.

To that, the other week I measured CYA of about 60 (aiming for 80). Pool math told me to add just over 1Kg of CYA to the pool. I've checked again today and it is still around 60. The FC level is now 6.5, and wondering why the CYA hasn't come up? Should I add another 1Kg of CYA, or perhaps aim for 70 and lower FC? Could recent rain and water top ups diluted the CYA?

On another note, is pH of 7.5 a bit low? The CSI in pool math really prefers 7.7 and above but my instinct (and the quality of the pool water) tells me to keep it at that level. I'm using about 5L of acid a month to keep it at that level (pool is almost a year old).
 
Glad to hear TFP is treating you well. As for the CYA not rising - hard to tell. Once you add the amount noted on the calculator, and give the granules about a week to acclimate to the water, the level should increase. Of course CYA is the trickiest of all tests to perform, even for the most seasoned TFP'er, so there's always that "+/- error factor" to consider. Every once is a while, we hear of some stabilizer on the shelf that just didn't seem to have an effect, like a bad batch. If it's been a solid week and there was no change, and you're sure your test was accurate, you may want to try to increase by 10 ppm.

For pH, you ideally want to be in the 7.6-7.8 range for your type SWG pool. Adjusting up slightly (maybe just with some aeration) won't have any effect on your water clarity. As long as your pH, TA, and CH are within the recommended ranges, your CSI will be just fine. Nice work maintaining your pool!
 
The CYA test has a measurement tolerance of +/-15ppm. If you only raised your CYA by 10ppm, you might not see that in the test.

When making small adjustments to CYA, I find using dichlor powder to be more effective. Dichlor powder dissolves rapidly into water and every 10ppm FC increase raises the CYA by 9ppm. It will not lower the pH and TA as much as trichlor does and it also avoids the hassle of using granular CYA and waiting for it to dissolve. You can chlorinate with dichlor until you measure the CYA level you want and then switch over to bleach or let the SWG handle it. I usually lose about 10ppm CYA over the winter months and it's cheaper to buy a bag or two of dichlor powder than a 6 pound bucket of granular CYA.

Yup, that's right, I said use stabilized chlorine powder :shock: It's one of the few contexts you'll actually get that kind of advice from me :D


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
Ha! I have never used/bought pure CYA. I only use DiChlor as I like the instant result. I used it when I got a new liner to start up my CYA, and now use it for any minor CYA adjustment. (My CYA level is low: 30-40).

I have not had a problem with significant pH lowering, even though PoolMath indicates that I should. (I do have borates so that might help).

Added for Dave :rolleyes: : Newbies need to be careful of DiChlor unless they have researched the effects, though.
 
There is nothing wrong with stabilized Chlorine if you mind what you are doing. The important thing is knowing the effects of what you put in is all, and that goes for every single thing we teach.

You'd think there was a TFP P.O.W. camp somewhere for those approving it's use on this forum. It's not even close to the truth.
 
It will be better for your pool and your SWG cell to keep your CSI slightly negative, -0.1 to -0.2. You can also let your TA drop to 70 or even 60 to help reduce PH rise.

Hmmm, maybe I should get on this dichlor bandwagon. :)
 
Thanks for the feedback all.

I never heard of DiChlor or if it is even available locally. It could just be a Fad?!

I'm happy for the SWG to do all the work and add liquid Chlorine as and when it needs an instant hit.

I've added a bit more CYA and will recheck next week to see where it's at.
 
1,3-dichloro-1,3,5-triazinane-2,4,6-trione

Or

Dichloroisocyanuric acid

It's stabilized chlorine (adds both FC and CYA) and is similar to trichlor. It mostly exists in a powder form and is sold in almost every pool store as pool shock. You can walk into any pool store in the USA blindfolded, throw a stone and pretty much hit this stuff with every throw it is so ubiquitous. My guess is Australia has lots of it too.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 

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Any labeling requirements in Australia?

In the US, chemical product manufacturers are required by law to list active ingredients using either specific chemical names or their generally recognized trade names.


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
 
It is more likely that repeated acid additions to lower your PH has resulted in lower TA which has helped to stabilize your PH. Or maybe you are running water features like waterfalls or bubblers less? That would also reduce PH rise.
 
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