I have an established, inherited pool that has lived on pucks for likely decades. The CYA is currently off the charts. I have a TF-100 kit but I'm not sure which chemical to bring under control first before I start up my intellichlor. Should I aim for making sure my pH is correct before I drain and retest CYA or can I just drain and fill and get my CYA in a ballpark range before going through all the tests?
High CYA - what to do first
- Thread starter bizzle
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b,
Since the only way to get your CYA down is to drain some, or even all of your water, it only makes sense to drain and refill first, and then attack the other chemical levels..
Thanks,
Jim R.
Since the only way to get your CYA down is to drain some, or even all of your water, it only makes sense to drain and refill first, and then attack the other chemical levels..
Thanks,
Jim R.
check the thread at the top of this forum. diluting test for CYA. I just found out about this method and it will be a first for me to try as well.
- Jan 4, 2016
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Not sure about your situation or if you've covered this elsewhere, but draining a pool is a big deal and has risks. You can float the fresh water on top and suck the CYA laden water out the bottom, in most cases, especially this time of year with cool pool water. It will work as long as you introduce the fresh water gently, and remove water at around the same rate.
Also, be sure your utility doesn't use March water usage as part of your sewerage charge estimate.
Also, be sure your utility doesn't use March water usage as part of your sewerage charge estimate.
I've got two hoses in the skimmer on one end and draining from the main on the deep end.
In any case, it's mixing right now so I can check CYA in the morning. I really don't want to have to drain and fill this pool 10 times or more but that's probably what I'll have to do. Then I'll lower my pH and SLAM...hopefully getting this under control before "summer" hits.
In any case, it's mixing right now so I can check CYA in the morning. I really don't want to have to drain and fill this pool 10 times or more but that's probably what I'll have to do. Then I'll lower my pH and SLAM...hopefully getting this under control before "summer" hits.
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- Jan 4, 2016
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The cold pool water is to your advantage and you'll lose the least water doing it all in one go rather than some/mix/test. You can test to get your CYA and then math to know how much new water to put in. Then measure your flow rate by how many seconds to fill a 2 gal bucket. Then you can know how long to run the fresh water, draining as needed. It won't mix much, so it's quite predictable.
The CYA is still too high to test so I can't follow that suggestion yet. I need to get it down to at least the hundreds before I can even do a dilution test.
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- Jan 4, 2016
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No worries. Although this is not an approved method, you can use a measuring cup and a bowl to get a rough idea where you're at. Take 1 cup of pool water and add it to the bowl. Use the same measuring cup and water filled to the same 1 cup line, and add a cup of tap water four times. Mix it up and do the CYA test. Multiply your result by 5. Or make it 9 cups of tap water and multiply by 10. The more careful you are with the measuring, the better the ballpark figure, but it's still just ballpark.
CYA gets slowly depleted from pool water by splashout, backwashing, leaks, and also some depletion from oxidation, perhaps 5 or 10 ppm per month if you've been dumping a ton of chlorine in to keep it from turning green. So you won't have every bit of it from the beginning. In really bad pools in your situation, we often see CYA over 300, sometimes 350 ppm CYA, but let's say 400 ppm CYA just as an example.
Assuming a 400 ppm CYA start, 4 drain/refills of 35% would reduce the concentration to 70 ppm CYA which becomes manageable. I haven't heard of 1000 ppm CYA, but if it was, then it would be 4 drain/refills of around 50%.
Nothing wrong with what you're doing, just threw out the layered exchange method as an option to reduce the time, effort and water. Don't let the plaster get dried by the sun. Good luck with it.
CYA gets slowly depleted from pool water by splashout, backwashing, leaks, and also some depletion from oxidation, perhaps 5 or 10 ppm per month if you've been dumping a ton of chlorine in to keep it from turning green. So you won't have every bit of it from the beginning. In really bad pools in your situation, we often see CYA over 300, sometimes 350 ppm CYA, but let's say 400 ppm CYA just as an example.
Assuming a 400 ppm CYA start, 4 drain/refills of 35% would reduce the concentration to 70 ppm CYA which becomes manageable. I haven't heard of 1000 ppm CYA, but if it was, then it would be 4 drain/refills of around 50%.
Nothing wrong with what you're doing, just threw out the layered exchange method as an option to reduce the time, effort and water. Don't let the plaster get dried by the sun. Good luck with it.
I did as you suggested at the end of my last drain/fill and ran water from one end to the other for a few hours. Today I'm down to measurable CYA @60. One more deep drain/fill and I should be ready to SLAM.
- Jan 4, 2016
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Excellent news!! You could SLAM at 60 or will be even better a bit lower. Great progress
OK, well that initial test was diluted and when I re-tested it's *now* between 60 and 50 CYA non-diluted. If I slam at 60 poolmath is indicating I need roughly 6 gallons of 10% Cl to get it up to shock levels. If I bring CYA down to 30, then I'll need less Cl (almost 3 gallons) but I'll also need to buy nearly 8lbs of stabilizer to get it back up to 60-80 for my SWG.
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DeanP66
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You should be fine doing a SLAM with CYA 60. Just check and redose frequently. Plus, if you've just emptied out a lot of water, it shouldn't take too long till your good to go.
- Jan 4, 2016
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Other than the initial dose, it should take around the same amount of FC because the FC has X amount of stuff to kill. You might use a little bit more just because of the practical side of raising it a bit high when you know you can't get back to it in time, but it won't be much.
And even with the higher initial dose, you might see an extra day or two of FC holiday at the end if the SLAM as it comes back down to maintenance level.
And even with the higher initial dose, you might see an extra day or two of FC holiday at the end if the SLAM as it comes back down to maintenance level.
Well, the problem was less about the CYA and more about the CH (800+; turned blue and then turned back to purple after about 5-10 minutes) when I ran my battery of tests so I'm doing another partial drain before starting the SLAM.
I'm in the middle of my SLAM and is there anything I can do to cut down on the reagents for the FC test?
Here are my test results so far:
Sunday Noon SLAM initial testsFC 0
CC 0
pH 7.0
TA 130
CH 625
CYA 40
SALT 550
TEMP 78
Added 4 gallons 10%
3pm 3 hours after SLAM
FC 14
CC .5
11am Monday
FC 10.5
CC 1.5
1/2 gallon every 3 hours
2:30pm
FC 14
CC .5
9:30am Tuesday
FC 12.5
CC .5
1/2 gallon every three hours
3:30pm
FC 14
CC .5
10:30pm
FC 14
CC .5
9:30am Wednesday
FC 15
CC .5
1/8 gallon every hour
6:30pm
FC 13
CC .5
Here are my test results so far:
Sunday Noon SLAM initial testsFC 0
CC 0
pH 7.0
TA 130
CH 625
CYA 40
SALT 550
TEMP 78
Added 4 gallons 10%
3pm 3 hours after SLAM
FC 14
CC .5
11am Monday
FC 10.5
CC 1.5
1/2 gallon every 3 hours
2:30pm
FC 14
CC .5
9:30am Tuesday
FC 12.5
CC .5
1/2 gallon every three hours
3:30pm
FC 14
CC .5
10:30pm
FC 14
CC .5
9:30am Wednesday
FC 15
CC .5
1/8 gallon every hour
6:30pm
FC 13
CC .5
- Jan 4, 2016
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try a 5 ml sample where 1 drop = 1 ppm.
switch back to 10 ml for Overnight Chlorine Loss Test
Keep up the good work on your SLAM. Going well!
switch back to 10 ml for Overnight Chlorine Loss Test
Keep up the good work on your SLAM. Going well!
Last night my FC was at 32-33 drops (16 ppm) and this morning I was at 28 drops (14 ppm). Is my SLAM over if all the other criteria are met since that's within the test's margin of error?
- Jan 4, 2016
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That's a famous question around here, but the answer is no. It's a 1 ppm drop or less to pass OCLT.
That said, let the FC drop on it's own to around 8 or 10 ppm and re-do the test. It should take a couple days to drop, so enjoy the FC holiday!
That said, let the FC drop on it's own to around 8 or 10 ppm and re-do the test. It should take a couple days to drop, so enjoy the FC holiday!
The problem is that at these chlorine levels, there's no way to be certain of a 1 ppm drop. The instructions claim a 10% margin of error. Ignoring tester error, the test from last night was 29-35 drops (14-17ppm) and the test this morning was 25-31 drops (12-15ppm) so my pool's chlorine experienced somewhere between a 1 and 2ppm drop.
What is the reasoning for letting it drop to 8-10 FC? Temps are mid-90s now and my CYA is only at 40 so I think it'll only take 1-2 days. I didn't add any liquid chlorine today but I did run my IC60 at 100% (.5ppm/hr) for nearly 12 hours and my Cl started at 14ppm this morning at 7 and ended at 15ppm at 9:30 so I lost 5ppm to whatever load it still has and the sun today. How much chlorine loss is expected when a pool is in full sun all day in mid-90 degree weather at 40 CYA?
What is the reasoning for letting it drop to 8-10 FC? Temps are mid-90s now and my CYA is only at 40 so I think it'll only take 1-2 days. I didn't add any liquid chlorine today but I did run my IC60 at 100% (.5ppm/hr) for nearly 12 hours and my Cl started at 14ppm this morning at 7 and ended at 15ppm at 9:30 so I lost 5ppm to whatever load it still has and the sun today. How much chlorine loss is expected when a pool is in full sun all day in mid-90 degree weather at 40 CYA?