Need to SLAM and don't have accurate CYA level

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JoanC

JoanC

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May 26, 2012
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Rome, GA
Hi all !
I'm needing some help with a couple of things and verification on what I'm thinking of doing.

Numbers as follows with TF -100
ph - 7.8
FC - 1.5
CC- 3
TA - 60
CH - 75
CYA - ? slightly cloudy but still see dot fine even at top of cylinder.

Water is crystal clear with no signs of algae, small amount of debris in deep end. I will vac this out. Had planned to do so today anyway.

Last bleach (10%) put in day before yesterday to raise Cl to 5ppm per pool calculator, presuming I still had CYA at 30.

Days have been hot and sunny in mid to high 90's so expecting some Cl loss.

CYA test and I don't like each other. I ordered CYA standard test solution today to see if I'm wrong or something else. I also ordered new reagent and cylinder.
I estimated 10ppm CYA in pool so pool calc said add 4lbs 14oz. Got it in pool now. Granular, 100%, in pantyhose in skimmer basket. I know won't show up for about a week.

I used CYA of 30 to determine my chlorine level for shock since that is my target and I need to get started.

Do I have your approval so far?

I have only used bleach since last year and with exceptional results but, I do have 3-4 bags of cal hypo 73%. I know it makes water cloudy.
If I use it one time, then continue the shock process with bleach, will the bleach clear up the cloudiness?

I'm off to brush the pool like crazy and hope I dislodge whatever is growing in it all of a sudden!!!

Thank you,
Joan
 
Thank you Jason.
Since the chart doesn't go down to CYA of 10, should target be 5?
I based this off of how the others seem to be calculated except for change at CYA of 20 which appears to be .2 as divisor.

Thank you again,
Joan
 
Jason,
I found Chem Geek's chart which says, " 4.5" for CYA of 10.
Should have looked for it to begin with and not have bothered you.

Thank you for your help.
Joan
 
Thank you Jeff.
Chem Geek's chart is from 2007 and I wondered if that was still current practice.
Everyone is good about keeping information up to date on here so I thought it probably was but evidently thinking has changed.

I will re-calculate again.

Thank you,
Joan
 
Using a shock level of 10 ppm for any CYA from 0 to 20 ppm is fine. My chart just showed consistent active chlorine levels, but when one gets to low FC it gets risky to run out and that can cause more work than initially overshooting to a higher FC. Just use 10 ppm.
 
Thank you for responding Chem Geek.
I feel like I've been blessed by God just by you responding.
I love your posts explaining the chemistry in detail so one knows the why and how of what we do with our pools to keep them looking good but most of all safe to swim in.

There are so many members with great intelligence and I truly appreciate all of you taking time to help me.

SLAM is underway with target of 10 for today.

Thank you all again,
Joan
 
I began the SLAM process yesterday using FC target of 10.
Last testing last night was FC- 9.5 CC- 1.5. I added bleach again for target of 10.
I felt pretty good going to bed on that with no sun to sap the chlorine out.
0730 this morning FC- 5.5 & CC - 1.0 Something used it up. FC target today of 12.
Brushed and went looking for anything I may have missed with a toothbrush. I took ladder out and cleaned with bleach but really didn't need it. But the rubber stops on the bottom, that go up against the wall- when I checked them, they had a little dirty tint to them and inside them was dirty so cleaned them with bleach. I also scrubbed around the skimmer framing with a toothbrush and there I did brush out some algae. I used the toothbrush around all the returns and one of them had some gray come out from the surround. Light in pool had nothing come from it nor did the banding at steps. I always brush them when brushing the pool.
1230 --FC 3.0 & CC- 1.0
1530---FC 1.5 & CC- 0.5 -1.0 ( faint pink so added one more drop and considered it a 1.0) Hot and sunny today!
1900-- FC 3.5 & CC- 0.5- 1.0 ( same faint pink so still did one more drop and considered 1.0)

Target FC for SLAM is 12 as stated above. Remember I'm estimating CYA at 30. I'm wondering about bumping up the chlorine a bit to try to wipe out the CC.
Considering there is the possibility that the CYA could even be 40.
The CYA is almost dissolved in skimmer. I keep massaging it! Should be gone by morning.
My pH has dropped to 7.2 and oddly my TA has dropped to 50. Solution is pink at 50 and very dark pink or red at 60 so perhaps 55?
Doesn't CYA cause pH to go down a bit?
Anyway, what do you think about a little more chlorine in tonight?
I know pH isn't reliable during SLAM so just wait until I'm finished to address the pH and the TA?

You guys are great!

Thanks in advance!
Joan
 
Yes I would raise your shock FC level up to the CYA level you shot for. If you shot for 30, take it to 14. The key to this is testing as often as you can, every 2 hours would be great and maintaing the shock level. When FC drops below shock level bring it back up. Your losing FC because something is consuming it.
Yes, the CYA will lower PH as it is acidic. ?
 

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Thank you for the responses pwrstrk & MBG75.

Yes, I did add 10% bleach between all the tests,per the pool calculator figures for FC target of 12 which is for CYA of 30.
I can't remember how many gallons I've added since starting yesterday but I bought 8 today and have already used 7 & 1/2 gallons of those today.
I went back to pool store to buy more late afternoon and they were out so ran by Walmart and got some 8.5% till I can get some of the 10% which comes in full gallons and costs almost the same as the Walmart brand so it's a better buy.
I think I wasn't clear with my question regarding adding more chlorine/bleach, especially without letting you know I had done additions all along. You can't read my mind. Only what I type!
I was asking about adding more bleach than the target for a CYA of 30 since I'm not certain of the amount CYA in the pool. It should be around 30-40 when it registers by the end of the week.
Whether aiming for a higher CYA target FC or overshooting the one I'm using, would it get rid of the 0.5 - 1.0 that won't seem to budge?
I have read where other members have added maybe a gallon more than calculated and that finally pushed out the last little CC for them.

By the way,
10:00 pm FC --7 CC -0.5 -1.0 ( still very very faint pink after one drop so added another for crystal clear. still calling it at 1.0 )
Have not done calculations for tonight's bleach yet. Will check back once more before dosing to see if either of you or anyone gave opinion.

thank you so very much!
Joan
 
Day 3 of SLAM.
Water continues to be crystal clear in daylight. With last testing and dosing last night, I saw tiny bubbles in water in front of pool light.
We rarely swim at night anymore and I don't recall if this is normal or not.

0700 numbers before sun on pool - FC- 7, CC- 0.5-1.0 (still saw very faint pink so added another drop for absolute clear as yesterday). Added 8.25% bleach for target of 12

Brushed pool including all around light housing, step banding and other hiding places as vigorously as I could. No flare up from anything.
Emptied few leaves from skimmer. There were about 5 worms in the deep with a little debris. Sometimes worms seem to fall from the trees, of which, we do have many.
I will vac debris a little later but know from past it will blow back through returns. This has been a problem this year and have been thinking it could be a contributing factor although I have not had a problem with the Cl level until this past weekend. I have searched posts concerning that issue and am working on it also.

0900 - FC - 13, CC- 0.5 No bleach added as this is 1 over FC target of 12
Will recheck soon. Another sunny, hot day so will probably need a good bit added to maintain target.

pH -7.2 today as it was yesterday. As posted yesterday, should I be concerned? Should I aerate a bit to raise it or wait until SLAM is over since pH not reliable during SLAM.
Also my TA will need to be raised a little after SLAM and I know that will raise my pH at that time but what about now?

I test as often as I can to keep the level up.

Thank you so much,
Joan
 
Will do and thank you for staying with me Jeff!

1030 results: FC - 11.5, CC- 0.5 Will add bleach to bring back up to target and retest soon.
Hopefully even with sun today all will go well and tonight I will pass the big test!

Daughter has already text about it being okay to swim today. Granddaughters are bugging her. I'm not on their good list with pool being clear and looking fine.
Daughter is a biology and chem major from years past and I'm an RN. She KNOWS as well as I do, we are fighting organism lag time and the importance here.
I'm also fighting time constraints but trying my best to not let the critters grow before another shot at them.

Thank you so much,
Joan
 
Added bleach for target of 12 at 1100.

Results at 1200: FC - 11, CC - 0.5 (very faint pink before adding the one drop. Getting close to 0 I hope!)
Adding bleach 8.25% for target of 12.
 
JoanC said:
Will do and thank you for staying with me Jeff!

1030 results: FC - 11.5, CC- 0.5 Will add bleach to bring back up to target and retest soon.
Hopefully even with sun today all will go well and tonight I will pass the big test!

Daughter has already text about it being okay to swim today. Granddaughters are bugging her. I'm not on their good list with pool being clear and looking fine.
Daughter is a biology and chem major from years past and I'm an RN. She KNOWS as well as I do, we are fighting organism lag time and the importance here.
I'm also fighting time constraints but trying my best to not let the critters grow before another shot at them.

Thank you so much,
Joan
Click to expand...
Let the FC drop a little bit, hand the kids some goggles and brushes, and let them get in provided they scrub the walls for you. Raise the FC back up after they get out. It's win-win.

They'd swim in a lake with far more green and far less visibility, right?
 
Big smile here Richard!
Was hoping you might chime in and say that.
The thought did occur to me since the CC is at 0.5
Now if the sun will help me out with the FC getting down a bit.

Do you think the pH of 7.2 will irritate them much?
I can turn the jets up a bit.
I don't mind if I have to lower it later when I add baking soda to increase the TA a little.

And by the way, they DO go to the lake and just got back from the beach.

Thanks bunches!
 

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