CYA of 120.... so this is what its like...

[gtnos]

i added 70 oz of stabilizer to my pool friday to bring the CYA up to 120 from 40. our new pool will *hopefully* be done this weekend and our water pumped from our intex pool into the new one. once combined with another 14000 gallons, we should have a instant reading of ~40 ppm.

since I upped my cya, it is now taking 58 oz of bleach a day (up from a mere 20 oz) to maintain its crystal clarity and my ph has crashed (below 7.0) twice now and I have had to add borax to bring it up .the pH is unstable, fluctuating everyday from 7.0 to 7.8 day to day. my TA took a nose dive too from 90 to 60.

I am posting this for all beginners to see. This is what happens at high CYA levels. Everything just goes to pot. Before skyrocketing my CYA level up to 120, my pool was perfect, TA at 90 and pH at 7.4-7.7 every single day and only losing 1 to 2 ppm per day of FC. I have never had to add borax or soda to my pool before. Now its a daily fight just to keep this thing clear and swimmable.

I will be so glad when the new pool gets up and im back to normal.

 

[jblizzle]

I started reading and asked myself, "what the bleep is he doing?"
Then I remember why you were doing it.

I can only guess that it was the addition of the stabilizer that lowered the pH and TA. With the lower TA, apparently the pH is swinging (a little odd).

I am a little surprised that you are needing to use more FC everyday. The losses to the sun should be lower. I would have thought you may need the same of less bleach everyday, just at a higher FC level

 

[anonapersona]

So, how about adding a bit of something to raise the TA to 70 or 80? Should stabilize the pH, I use baking soda.

 

[JasonLion]

Something else is going on. Adding CYA should not have had the effects you describe. I don't see any hints to what it might be, but there has ti be another factor involved.

 

[Isaac-1]

We need chem geek on this one, what happens when you give a pool a massive hit of CYA....

 

[Swordfish]

Wonder if the additional cya is doing its thing with the chlorine...thus increasing the demand until it stabilizes. Perhaps it's just more noticeable in a smaller volume of water, since I don't remember much additional domand when raising my cya. Interesting numbers and thread...

Sent from my head, with the help of my fingers and a wireless device; perhaps inconveniencing some electrons along the way

 

[Richard320]

I never experienced things like that with twice the CYA you have.

I guess you're just not man enough to handle that much CYA.

 

[gtnos]

I never experienced things like that with twice the CYA you have.

I guess you're just not man enough to handle that much CYA.

guess not. I donno guys, but that is what im seeing. have had some days where it was only 30 or so ounces of bleach. probably got something growing with that high of a cya making my FC useless. maybe I should SLAM it before I transfer it. oh right, thats tomorrow. no time to SLAM. Ill just transfer it, top off the new pool, run the pump overnight and hit it with a full battery of tests the next day. any issues then and ill iron them out.

 

[chem geek]

CYA is acidic and for the amount that you added it will lower the pH from 7.5 to 6.9 though with carbon dioxide outgassing it probably won't go quite that low. However, there should have been no change in TA because what got lowered by the acid got exactly compensated by cyanurate which gets measured as part of TA. So that part is a mystery. The pH fluctuating is also mysterious except for your lower TA (that shouldn't have been lowered). It's behaving as if there was some pure acid (like sodium bisulfate dry acid) in the CYA you used. Interestingly, 70 ounces of dry acid would lower your TA by 32 ppm which is about what you saw.

As for needing more bleach per day, that is most likely caused by algae growth because if you didn't raise your FC target to at least 11 ppm, then algae could start to grow and will therefore require more chlorine. You can verify if this is the case by measuring your overnight chlorine loss. Your loss from sunlight should have gone down.

 

[gtnos]

hey chemgeek! thanks for replying. I ALWAYS split the difference on the TFP recommended FC settings. for 120 CYA the pool calc said 9- 15 so I set my goal for 12.

interesting what you said about CYA having dry acid..... this was not the normal brand I use. normally I use HTH from walmart. this was some off brand stabilizer given to me by (wait for it... wait for it)..... yup, the pool store. :-x

it was part of the "start up chemicals" they give you with a new pool.


should have known it was garbage.....