CyA not calculating correctly?

[Agrabah]

I’ve noticed that when I need to add cyanuric acid the numbers that pool math comes up with seem extremely high so for example I recently had to refill my pool so I started with zero and it wanted me to add about 5 pounds and 7 ounces of dry stabilizer when I did actually add it I always do it in increments anyway, but it said for me to get from 0 to 60 it should’ve been about 5 pounds What actually happened was I added 1 pound to separate times within 12 hours and after about 24 hours tested my cyanuric acid levels and it came in about 50 ppm

All other estimates seem to be very spot on and just for reference when I’m measuring I use a weight scale with a measuring cup and I zero out the weight with a measuring cup on it so I add exactly 16 ounces so I’m not sure if it’s an issue with how I’m measuring it and I’m I’m measuring it incorrectly or this specific stabilizer is just much stronger per weight.

I can understand it being off a bit but if I added exactly what it wanted I would have to drain and refill as the numbers would be well over 120.

Edit: to add, a few months back I had a reading that wouldn’t show up as it was below 30. Expected about 20. Pool store measured it at 24. To go from 24 to 60 it wanted about a pound. I added 8oz and it shot up to 60 after waiting 24 hours. So really not sure. Based on other threads, my size pool should be about 11 ppm per 1 pound but that’s definitely not what I’m getting.

 

[Jimrahbe]

A,

I am not sure where the problem is, but adding 5 lbs. of dry CYA will get you to 55 ppm in a 10,800 gallon pool.

I don't think the calculator is off.

Let's see what some of your chemicals guys have to say.

Thanks,

Jim R.

 

[JamesW]

I added 1 pound to separate times within 12 hours and after about 24 hours tested my cyanuric acid levels and it came in about 50 ppm

Assuming the pool volume is correct, each pound should result in a 12 ppm increase.

2 pounds should result in a 24 ppm increase.

Did you do a 100% drain and refill?

 

[JamesW]

How did you add the CYA?

 

[Texas Splash]

We understand the CYA test can be a bit subjective, so it's not uncommon to see a variance of about 10 ~ 15 ppm on any given CYA test. But what you are describing are extremely large variations that fall well outside what we would consider a standard testing deviation. You are welcome to tell us which brand stabilizer you have been using, but I doubt the stabilizer itself is to blame. If the pool size is correct, our next recourse would be to confirm how you are testing.

Can you describe your CYA testing process?

 

[Agrabah]

Assuming the pool volume is correct, each pound should result in a 12 ppm increase.

2 pounds should result in a 24 ppm increase.

Did you do a 100% drain and refill?

View attachment 484374

100% drain and refill. I'm going to post another thread about it today/tomorrow, in detail, but I don't want to derail this thread

I'll take another measurement later this afternoon myself as well as have a store check the sample for comparison.

 

[mknauss]

I'm going to post another thread about it today/tomorrow,

Keep in one thread. We can move this thread to a more appropriate sub forum.

 

[mknauss]

as well as have a store check the sample for comparison.

No pool store can test CYA as well as your kit can. It will only cause confusion.

 

[Agrabah]

How did you add the CYA?

Weighed and added to skimmer sock.

We understand the CYA test can be a bit subjective, so it's not uncommon to see a variance of about 10 ~ 15 ppm on any given CYA test. But what you are describing are extremely large variations that fall well outside what we would consider a standard testing deviation. You are welcome to tell us which brand stabilizer you have been using, but I doubt the stabilizer itself is to blame. If the pool size is correct, our next recourse would be to confirm how you are testing.

Can you describe your CYA testing process?

Sample water @ 7, add testing reagent to 14, shake vigorously for 30s. Put it down to waist-height and add liquid until it goes cloudy, wait a few seconds, shake bottle some more, add more slowly until dot completely gone. Only difference in this case was it wasn't with full sun overhead but I wouldn't expect a 30 ppm measurement difference with sun, but maybe that's it?

 

[JamesW]

Did you take a sample near a return while the CYA was in the skimmer?

 

[Texas Splash]

A couple things I would recommend on your next test:
1 - Do no shake vigorously. On the initial sample fill in the bottle, gently swirl it around then let it sit for 30 sec. Then gently swirl before squirting into the viewing tube. But no vigorous mixing.
2 - Do it on a sunny day. You really need that better lighting.

 

[Agrabah]

Keep in one thread. We can move this thread to a more appropriate sub forum.

It really is unrelated but...

PB set up a warranty repair for my Hayward Colorlogic LED light. I was told that the pool did NOT need to be drained. The company it was assigned to (PB is basically just a general contractor so they don't do it in house) contacted me to let me know pool needed to be drained. I fought it but they claimed Hayward required it. I called Hayward and the support person on the phone said that's untrue and they have no policy requiring that but refused to give it to me in writing. I ended up submitting because it was the only way I was going to get the light replaced. Water was warm enough to do it from inside but they just refused to do it. Used a pump to pump out the water below the light as requested and then they came back and said it needs be below ankle so I pumped the rest out. They were supposed to come out the day it pumped down to the bottom. Well, their guy "called out sick" and I had a small amount of water sit at the bottom of the pool for a little over 24 hours which ended up causing a water stain ring which I am now fighting them on. I am hoping brushing over the next few weeks will help reduce/eliminate it but it still has me pretty heated. I was going to upload some pictures as well because I was hoping for advice on fixing it, preferably without draining again. I ended up emailing Hayward and did eventually get it in writing that draining a pool is unnecessary but a pool company may require it because of temperatures or whatever. Which I agree with, but the company was (and still is, even after I provided proof) claiming that it was a Hayward directive.

 

[Agrabah]

Did you take a sample near a return while the CYA was in the skimmer?

No. After it was dissolved completely.

 

[ajw22]

I had a small amount of water sit at the bottom of the pool for a little over 24 hours which ended up causing a water stain ring which I am now fighting them on. I am hoping brushing over the next few weeks will help reduce/eliminate it

How long has it been since you refilled the pool?

Brushing is not going to do anything to the ring.

How deep is your pool? Can you reach an area of the ring and sand it with some 80/100 grit wet/dry sandpaper?

What type and color is your finish?

Maybe @onBalance has ideas.

 

[mknauss]

ended up causing a water stain ring

Stain is either organic or metals. If organic, it will go away with the FC levels maintained in your pool water. It might be iron (our water has some iron in it). Get a thin sock, put a handful of vitamin C tablets in it, crush them up a bit, and place the sock on the stain. Use your brush to hold it down there if necessary.

 

[Agrabah]

Stain is either organic or metals. If organic, it will go away with the FC levels maintained in your pool water. It might be iron (our water has some iron in it). Get a thin sock, put a handful of vitamin C tablets in it, crush them up a bit, and place the sock on the stain. Use your brush to hold it down there if necessary.

No metals in our water, however, my stone coping is not sealed (PB was supposed to but didn't) and I believe that the stone might be leeching out iron when wet but I was also told it shouldn't be enough to ever affect the metal content in the pool enough to cause any kind of staining and was more aesthetic than anything.


I was told this is a water stain ring from where the water was sitting so it kind of looks like a shadow.

 

[mknauss]

You are using Colorado River water. It has iron in it.
The stain comes from the evaporation of the water as you let it sit. The metals or other items concentrated as it evaporated.

Try the vitamin C.

Unless this plaster is very new, it should not stain from just water sitting on it.

 

[Agrabah]

You are using Colorado River water. It has iron in it.
The stain comes from the evaporation of the water as you let it sit. The metals or other items concentrated as it evaporated.

Try the vitamin C.

Unless this plaster is very new, it should not stain from just water sitting on it.

Finished in December so a little over 4 months.

The stain has slowly lightened up but still visible with water not moving. I did notice yesterday/last night some yellow/browning near the main drain which seemed to show up after PB added salt back, not sure brand they used but might just be a coincidence. Any suggestion on tablets? Does it matter if there's anything else in them? Any tablets I have seen are not pure Vitamin C and usually contain magnesium/zinc/other.

 

[mknauss]

Plain vitamic C is best. Might have what they call 'rose hips'. That does not matter.

Salt can contain iron also.

If the stain is lightening, it is likely organic (from leaves, etc that were in the water when it was very low).

 

[Agrabah]

Plain vitamic C is best. Might have what they call 'rose hips'. That does not matter.

Salt can contain iron also.

If the stain is lightening, it is likely organic (from leaves, etc that were in the water when it was very low).

Not doubting you since you all here have significantly more experience but we have very limited vegetation around us, the occasional leaf might blow over the wall. The majority of stuff that blows in are plastic bags or Styrofoam. The outline of the stain is exactly where the water was though. If it was from leaves or something I would expect to see it in one spot (similar to the yellow discoloration, I'll grab a pic later) and not the whole outline of where the water was sitting. Either way, the discoloration is annoying me more at this time. crush tablets, place in skimmer sock and use brush to hold down for a few minutes?