CYA at 100 after 80% drain and refill

[PetersonPool]

Hi all,

I'm a new pool owner as of last summer. TFP is a great resource and I feel confident I will be able to maintain the pool on my own now. When we got the pool and tested we discovered the CYA was at 100 and the pool water was always cloudy and really high in calcium and other dissolvibles so we planned a drain. It was sure hard to keep the chlorine up through the late summer and early fall! I did an 80%+ drain last week and took the water in to the pool store (waiting for my TF-100 to arrive). They said my CYA is 100! How could that possibly be?

On a good note is that using PoolMath and instructions I have the PH down right to where I need it to be with no problem. I'm keeping the Chlorine close to where it should be measuring with dip sticks until I get my TF-100 and I can get more accurate to get my daily dose down to a science.

Thanks,
Rob

 

[Texas Splash]

Hi Rob. A couple things .... disregard the pool store test. That's exactly why we recommend your own test kit. When your TF-100 arrives, test CYA 3-5 times yourself for practice and to get a good CYA average and you'll see why. Then you can treat accordingly. Your gut is already telling you, "80% water exchange, still high?" Also remember that when someone says their CYA was 100, it very-well could have been much higher. The CYA reading caps-out at 100, so you could've been at 200 or more. Glad you're seeing the benefits of the calculator. It is a great tool.

 

[PetersonPool]

Oh no. I didn't realize tests would top out at 100. Maybe I shoulda kept pumping water out. I sure don't want to have to drain again! My logic was I was going to need CYA anyway so I left some of the water there. That could have been a bad decision I guess. I'll let you know what I find as soon as I get my kit.

 

[MarianParoo]

Don't panic. Pool stores are notorious for getting CYA wrong. When does your kit arrive?

 

[JoyfulNoise]

^^^^^ +1

Many moons ago when I was pool-stored, they told me my CYA was 90ppm and "OK". Nope!! When I tested it myself, it was ~160ppm and most certainly not "OK"!!

Just ignore the pool stores. They can't get anything right.


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

 

[Isaac-1]

On the CYA test you can keep pouring the solution back and forth for several minutes until you are confident in your readings, you don't have to dump it out and start over.

 

[PetersonPool]

Yay! I got my test kit... bummer is I am testing 100 CYA. :-\

Someone (non-authority) said CYA is heavy and they've seen pools drained and still have CYA cause it 'hides in bottom and in the pipes'. Is there even remote truth to that? My guess is the CYA was just way over 100 and they just didn't know it because the test maxes out. It did take 3 days to drain the pool and I didn't have the pump in the very lowest part of the pool. If there is any chance I'd like to avoid another full drain. $$ Before it gets hotter could I let it set for a few days and then pump from the lowest part of the pool?

Thanks,
Rob

 

[Isaac-1]

There is no truth in CYA being heavy

 

[Donldson]

Someone (non-authority) said CYA is heavy and they've seen pools drained and still have CYA cause it 'hides in bottom and in the pipes'. Is there even remote truth to that?

Ha, just yesterday there was a post by someone who was told that CYA floats at the top of the water and acts as a sunscreen, now a day later you are told it sinks to the bottom. The Pool Industry: Where two "Professionals" can "know" two conflicting things and still both be 100% wrong. CYA mixes evenly in to the water. It is likely your actual CYA level was closer to 400 than the 100 that your pool store told you...

Pool stores, the Washington Generals of swimming pools.

 

[JoyfulNoise]

DEBUNKED!

Cyanuric Acid Location: Top, Bottom, or Everywhere?


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

 

[BuckeyeChris]

It does act as a sunscreen, though I believe that is just a general observational statement due to FC loss being less at higher CYA level. But it is not like a "layer" across the top, merely that as UV penetrates the water it goes through CYA-attached chlorine.

 

[Isaac-1]

I don't know about that, sunscreen implies in some way blocking the harmful part of the sunlight, where CYA acts more like converting a portion of the Chlorine into a form not prone to burning off under UV light.

 

[BuckeyeChris]

I don't know about that, sunscreen implies in some way blocking the harmful part of the sunlight, where CYA acts more like converting a portion of the Chlorine into a form not prone to burning off under UV light.

Chem Geek would say it does both. Otherwise the FC loss in relation to CYA level (keeping same ratio) would be linear, but it's not.

Chlorine/CYA Chart - Page 4

 

[borjis]

well since your above 100 you should do a dilluted test to get an idea what it actually is.

"Use half tap water half pool water and fill to the bottom of the label of red tipped bottle. Then fill to the top of the label with the reagent. Shake to mix wait 30 seconds. Shake once more. Pour into the view tube. When black dot disappears take your reading then double it. If your pool water is cold let warm to room temp. Cold water can sometimes affect the test."

 

[PetersonPool]

thanks for the responses and clarifications. In researching more on these boards I saw this same idea for the dilluted test to get a real idea of where it is. With that test I get a 60 so my CYA is still at 120. Wow, that means the CYA was at 500+. Sure wish I would have let the sump pump run another night for my original drain. Now I'm looking at a 70% drain again. :-( I sure wish I would have learned about the CYA 100 max reading before now!

I guess I should have spent some time learning more on these boards. I was curious if I missed something in Pool School, but went back and I don't see anything about the CYA max reading being 100. It seems like something to be a bit more obvious to help newbies like me. Just a thought.

 

[Texas Splash]

It's so easy to do (high CYA) when all we did in the past was take the advice of pool stores and friends who just say, "Shock it", "Get more tabs", "Toss 4-5 more bags in there". Well, at least you know now. Once you get that CYA down to something manageable (60-ish give or take) then you should never have this problem again.

 

[otter86753]

It's so easy to do (high CYA) when all we did in the past was take the advice of pool stores and friends who just say, "Shock it", "Get more tabs", "Toss 4-5 more bags in there". Well, at least you know now. Once you get that CYA down to something manageable (60-ish give or take) then you should never have this problem again.

This is true, but to a new person looking for advice, the comment above that the CYA could actually be over 100 is a valid one. They could have drained more water had they known that. It is hard to remember being that new person and not knowing everything you do now.

 

[JoyfulNoise]

It's in the Extended Test Kit Instructions - Extended Test Kit Directions

But I agree, it should be more clearly spelled out in Pool School somewhere.


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

 

[Texas Splash]

Yes Otter, you have a good point about being aware of the dilution testing. We are also cautious that even though some owners would prefer to do a 100% drain (or close to it), they may have some local limitations such as water table or drainage restrictions in their neighborhood. Even the dilution method of CYA testing is an estimate, so it's best to err on the side of caution. Inevitably, it's going to be up to the owner how much to drain at one time. In the end, it's great that PetersonPool has taken control of the situation and knows what to do to lower CYA. That's what TFP is all about - learning to do it on your own. I salute those who are taking control of their pool.

 

[otter86753]

Pat, That's exactly what I was talking about. Not just about CYA but lots of things that we all take for granted, but someone new doesn't event know to ask.