Calculating CYA adjustments

[NaiNot]

Thanks for the site. It's a wonderful resource.

I use Trichlor to bring CYA up to 40-50, then switch to 10% liquid Cl.

I am in southern Thailand, and we get mountains of rain between May and November, so I regularly have to switch between the two during this period.

Being in Thailand, it cost me over US$300 to land a TAYLOR K-2006C test kit, and the CYA reagents are getting used up pretty quickly.

I record all Trichlor added, and can measure how much rainwater enters the pool.

Knowing these two variables, is there a way to calculate changes in CYA without testing?

I would anticipate having to test CYA at certain intervals regardless of calculations.

Thanks for any thoughts.

Kenny

 

[Texas Splash]

Hi Kenny and welcome to TFP! Have you signed up for the PoolMath APP? In the APP go to "Effects of Adding" and you'll a way to monitor chemical adjustments. Hope that helps.

 

[duraleigh]

How often are you testing CYA? Once monthly is okay if you need to conserve.

 

[Newdude]

Knowing these two variables, is there a way to calculate changes in CYA without testing?

Simple math. rain water with 0 CYA will dilute you by an even %. If you get 15cm of rain in a 150cm average depth pool, it will lower your CYA by 10%

It will be less than that if you have an overflow drain because fresh water may drain before mixing, but you can guess the max that you could have lost. Once you start tracking it, you'll probably get a good idea for how it dilutes. It won't be perfect, but it will be close.

We only care about CYA in increments of 10, and because we round up, the change from 37 to 32 doesn't matter because both are a 40. Monthly tests, or whenever your guess thinks its time, will allow the reagents to last a long time.

 

[NaiNot]

Hi Kenny and welcome to TFP! Have you signed up for the PoolMath APP? In the APP go to "Effects of Adding" and you'll a way to monitor chemical adjustments. Hope that helps.

Thanks Texas

No, I haven't, but I will now.

I have been using the calculator at www.poolcalculator.com/calculator but the CYA section only covers "stabiliser" and "liquid stabiliser", not Trichlor.

Thanks for the tip.

 

[NaiNot]

How often are you testing CYA? Once monthly is okay if you need to conserve.

I've dropped back to about monthly now, but have felt the need to test after very heavy rain.

I'm just a newbie at the whole process, and am trying to establish a bit of a rhythm.

Thanks for getting back.

 

[NaiNot]

Simple math. rain water with 0 CYA will dilute you by an even %. If you get 15cm of rain in a 150cm average depth pool, it will lower your CYA by 10%

It will be less than that if you have an overflow drain because fresh water may drain before mixing, but you can guess the max that you could have lost. Once you start tracking it, you'll probably get a good idea for how it dilutes. It won't be perfect, but it will be close.

We only care about CYA in increments of 10, and because we round up, the change from 37 to 32 doesn't matter because both are a 40. Monthly tests, or whenever your guess thinks its time, will allow the reagents to last a long time.

Yes, after posting I realised that calculating decrease in CYA from dilution would be simple, but still want to be able to calculate increase in CYA from Trichlor use. Hopefully the Poolmath APP will help.

I didn't know about the increments and rounding. Sounds like I'm looking for an unnecessary level of precision.

Thanks Newdude.

 

[Newdude]

Sounds like I'm looking for an unnecessary level of precision.

You can be +/- 10 and it's still close enough for what TFP needs to do. +/- 10 is 3 values on the scale and I can guess your level decrease within that range from across the globe. You'll do even better up close.

 

[NaiNot]

You can be +/- 10 and it's still close enough for what TFP needs to do. +/- 10 is 3 values on the scale and I can guess your level decrease within that range from across the globe. You'll do even better up close.

OK, cool.

In this sense, how much chlorine is too much chlorine?

If, for example, I chlorinate to FC=5.7ppm (required for CYA=50 per www.troublefreepool.com/threads/chlorine-cya-chart.2177), but my CYA is actually only 25, that's not going to make my teeth fall out, is it...?

Of course the sunlight might eat a bit more FC, but hey, that's not as bad as my teeth falling out

Thanks again for your help.

 

[Newdude]

In this sense, how much chlorine is too much chlorine?

In any sense, chlorine is safe up to and including 40% of the CYA level (SLAM), even when youre off by 10. See FC/CYA Levels

You have LOTS of room to err on the high side and almost no room for error when you don't use enough FC. Always goof above target and not below.

 

[AUSpool]

Thanks Texas

No, I haven't, but I will now.

I have been using the calculator at www.poolcalculator.com/calculator but the CYA section only covers "stabiliser" and "liquid stabiliser", not Trichlor.

Thanks for the tip.

Go to the ‘effects of adding chemicals’ down the bottom of the page, every 100g of trichlor will raise your CYA by 2.8ppm in ~20,000L.

 

[NaiNot]

Go to the ‘effects of adding chemicals’ down the bottom of the page, every 100g of trichlor will raise your CYA by 2.8ppm in ~20,000L.

View attachment 462156

Fantastic, Steve. Exactly what I'm looking for.

Thanks heaps.

Is this in the PoolMath APP?

 

[AUSpool]

Fantastic, Steve. Exactly what I'm looking for.

Thanks heaps.

Is this in the PoolMath APP?

Yes it is. Click on the three bars, top left, then it’s the second option in the drop down menu, effects of adding.

Its a bit late now but ordering an extra bottle of the CYA reagent when getting the kit a good idea. Getting a K2006 here in Aussie is much the experience that you’ve had I expect. We have local company, Clear Choice Labs, that sells test kits and uses Taylor reagents so we are able to get some stuff local but not sure if it would be any use to you. Ooh, that speedstir thing is the best invention ever.

 

[mgtfp]

Being in Thailand, it cost me over US$300 to land a TAYLOR K-2006C test kit, and the CYA reagents are getting used up pretty quickly.

Is buying a 16oz bottle of R-0013 on Amazon an option for you? I bought one of them a while ago and it's still going strong...

 

[NaiNot]

Is buying a 16oz bottle of R-0013 on Amazon an option for you? I bought one of them a while ago and it's still going strong...

Thanks for the suggestion. This is what I am now investigating.

 

[NaiNot]

Yes it is. Click on the three bars, top left, then it’s the second option in the drop down menu, effects of adding.

Its a bit late now but ordering an extra bottle of the CYA reagent when getting the kit a good idea. Getting a K2006 here in Aussie is much the experience that you’ve had I expect. We have local company, Clear Choice Labs, that sells test kits and uses Taylor reagents so we are able to get some stuff local but not sure if it would be any use to you. Ooh, that speedstir thing is the best invention ever.

Might be the go. We're visiting in April, and I can probably stretch current batch out until then.

 

[Mdragger88]

Definitely buy the big bottle when you can. Keep it stored in a cool dark place (mine is in a closet) & only bring it out to refill your kit bottle. It will last for a long time. Its the most stable reagent.