I just had to pull the cover off!!

[98xc600]

I'm sure I should have waited till it was warmer, but I just couldn't take it anymore. first time going through a winter. We are starting to get highs in the 40's to low 50's and felt if I pulled the cover off it would start to warm up faster with the sun hitting it.
I also had to pull out my test kit (which reminded me I need to refill my kit) and was surprised at what I had for results.

FC 0 I understand why FC, CC, & TC numbers are what they are.
CC 0
TC 0
PH 7.3
TA 20 I tested this twice to see if it was me, and it came up the same number both times. When I closed the pool it was at 220, why did it drop so much during the winter? And is this a problem?
CH N/A
CYA 0. This was at 50 when I closed. Is that normal to drop to 0 over a winter?

The pool was frozen solid for 3-4 months. Still have a little ice floating around but hope to have that gone this weekend.

Thanks for any help!

 

[JasonLion]

It is common for CYA to go to zero over the winter. TA on the other hand, normally stays more or less the same.

 

[sefrlw]

Woa woa wait one minute. I thought that CYA could only be removed by drain and fill. He has only drained and not refilled yet. How can CYA go away?

 

[98xc600]

It is common for CYA to go to zero over the winter. TA on the other hand, normally stays more or less the same.

That's what I understood with reading the stickies. Then i come up with my numbers, could water temp be part of it???

 

[JasonLion]

CYA sometimes vanishes over the winter, often it stays the same. There is some process, no one is sure quite what but probably anaerobic bacteria, that can remove most or all of the CYA over the winter. This seems to happen about 1/3 of the time and is often associated with covered pools that get algae over the winter but sometimes happens in perfectly clean pools as well.

 

[98xc600]

Woa woa wait one minute. I thought that CYA could only be removed by drain and fill. He has only drained and not refilled yet. How can CYA go away?

Same question??

 

[The Mermaid Queen]

I believe water temps affect some of the tests, but I have no idea which ones or how they are affected!!

your water is gorgeous!!! but looks ice-cold!!

 

[waste]

CYA sometimes vanishes over the winter, often it stays the same. There is some process, no one is sure quite what but probably anaerobic bacteria, that can remove most or all of the CYA over the winter. This seems to happen about 1/3 of the time and is often associated with covered pools that get algae over the winter but sometimes happens in perfectly clean pools as well.

Jason, does it make any sense that the algae in the pools that have had the cya consumed over the winter is a result of the amonia the bacteria excrete? (I know sometimes folks close with algae in the pool, which would exacerbate the situation) Following this line of thought, the reason 98xc600's pool is algae free is because there is ice still in it - the water temp isn't high enough to support algae growth. If this theory 'holds water' , the pool will become a swamp as soon as the temp gets high enough for the algae to thrive - therefore, shocking the bejesus out of it while the water is still cold would be the best course of action (if the cya is truly gone, there's gonna be a lot of amonia [algae food] in the water)

Just thought I'd run this one up the flagpole and see if anyone saluted :-D

 

[JasonLion]

No, ammonia wouldn't be enough to break down CYA. CYA is fairly stable and none of the chemicals usually in a pool are going to affect it. Chem Geek has guessed that it must be a biological process, which sounds right to me. There are some kinds of soil bacteria that are known to break down CYA in the soil. It makes sense that some of them would be able to live in pool water if there isn't any chlorine, though we don't really know.

The practical question is what water conditions favor the loss of CYA and are there any other criteria, like covered/not covered that make a big difference. Right now we hardly know anything. Maybe eventually we will be able to come up with a process for lowering CYA, like we have one for lowering TA. Whatever that process might be it is going to be fairly strange, on the order of letting chlorine go to zero, throwing in some dirt, and covering the pool for a couple of weeks. It isn't going to be something most people are going to want to help us experiment with.

 

[ric]

Hi everybody...I am one that looses cya, ph, cl ,and yes ta. I live in north Ohio so winters are different year to year. The area is rolling farm land with plenty of wind that blows in the winter. I have a mesh cover and it lets plenty of dirt into the pool. I always open with low cya. and I do let the water raise to room temp before I test. I have noticed if it is a steady cold winter the pool will ice solid all winter and the water stays much cleaner but if the temps stay higher and I get 6 to 7 ice melts and lots of snow the water gets real cloudy. This year it was much wormer then usual and I cant see the main drain. If it is cloudy or clear in the spring my numbers always drop about the same and I treat this just like Algae I adjust the ph shock to 15 till it will hold and believe me it takes the bleach to get it to hold. I really don't think it is algae but like Jason and Waste claim it is probably bacteria and ammonia. I try to get everything started about Apr. 15. I don't have algae in the fall at closing I shock Wait a week and add polyquat water temp at closing 50 deg. and close. I think Richard or Ben had a paper on this but I cant find it know Sorry. I just thought you might want input on the weather conditions and climate on the falling cya. From what I have read this is normally a northern problem.

 

[waste]

Jason, maybe you misread what I was saying - or maybe I didn't properly explain it. I was thinking that the anaerobic bacteria consumed the CYA and excreted the ammonia (thanks for the proper spelling I was suggesting that the bacteria eat the cya and then excrete the ammonia, thereby causing the algae bloom in water warm enough to support algae growth

Ric - thank you for the 'field report' - we're all trying to figure out this phenomenon

 

[JasonLion]

Ah, yes they would consume CYA and excrete ammonia. But I don't think that would have much direct effect on the algae one way or the other because there are sure to also be other bacteria that will be producing ammonia through more efficient processes than breaking down CYA (which is comparatively difficult).

 

[98xc600]

So with all that said. I'll just raise the TA to 100 with some baking soda, bring up The CYA to about 40 and start to add bleach till all looks good. Thanks for your help!!!

 

[JasonLion]

I suggest raising TA to between 70 and 90, instead of 100, if you are using bleach. Try 100 to 120 for trichlor and 60 to 80 with a SWG. Also, remember to not put in the full amount of baking soda all at once, try 3/4 of the calculated amount to start, let it mix for a day and then retest and adjust from there. It is much simpler to raise TA than it is to lower it, so you don't want to overshoot.