Taylor k2006 test kit

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I am sorry to continue the question stream, but trying to get a grip on the best way to handle with drought issues. Does draining 8 in now, and again in next month etc help or will I make no progress. I might be able to have the water usage spread out over months during this time. Also is there any difference in cya levels requirements when temps are high and pool is in full sun from 11 am till 7 pm at this time of the year.
 
Every time you drain it 8" you will lower the CYA by 16% (assuming average depth is 48" and you are not adding any more).

So the CYA will progress like this:
300 > 250 > 208 > 174 > 145 > 121 > 100 > 84 > 70 > 58 > 48

So assuming you are starting at 300ppm and your average depth is 48", you will have to drain 8" 10 times to get the CYA in range.

Given the high amount of sun, you may be able to stop around 70ppm, but you certainly want to get below 100ppm.
 
Draining he 8 inches of water does nothing, but replacing it with water that has no CYA will lower your CYA level a bit. You will still have very high levels though.
 
Assuming your average pool depth is 4.75', then draining 8 inches and refilling (with cya free water...either tap or rain) will lower your cya to 260 (assuming 300 to start with). Not really a big difference...I probably wouldn't bother.
 
jblizze said:
Every time you drain it 8" you will lower the CYA by 16% (assuming average depth is 48" and you are not adding any more).

So the CYA will progress like this:
300 > 250 > 208 > 174 > 145 > 121 > 100 > 84 > 70 > 58 > 48

So assuming you are starting at 300ppm and your average depth is 48", you will have to drain 8" 10 times to get the CYA in range.

Given the high amount of sun, you may be able to stop around 70ppm, but you certainly want to get below 100ppm.
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Ok, I think my plan will be to drain 8 in each month, hope for rain. off tablets and shock, use polyquat 60 until I can get the cya down below 100. Am I on the right track now?
 
Yes, if you drain 8 inches of water and replace it with fresh fill (or rain), your CYA will go down.

Were you planning on leaving the pool down 8 inches until rain fills it? Are you closing the pool for the season?
 
techguy said:
Yes, if you drain 8 inches of water and replace it with fresh fill (or rain), your CYA will go down.

Were you planning on leaving the pool down 8 inches until rain fills it? Are you closing the pool for the season?
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I drained 8 in and refilling with fresh water. Intend to do that each month. Also hope for rain will continue doing this till cya is down. In Texas there is no closing for the season.
 
Donldson said:
From chem geek's personal experiences, as mentioned here:

chem geek said:
I can tell you from personal experience that Polyquat will not completely prevent algae growth, but it will slow it down. In my own pool 9 years ago, I was using Polyquat but only dosing every other week (one is supposed to dose every week because it breaks down from chlorine and can also get filtered out if water is dirty since it is a weak clarifier) and had algae start to grow faster than chlorine could kill it with 3 ppm FC and 150 ppm CYA. Had I used the Polyquat weekly, then I speculate I could have had the CYA get to perhaps 250 ppm but I don't believe that Polyquat alone would prevent algae growth when algae nutrient levels (phosphates, nitrates) are high.
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My take from that is he believes that he could potentially have had an FC of 3 with perhaps 250 CYA and prevent algae. I am thinking that since dkbrat's pool is currently clear it is probably low on nutrients, and thus with the polyquat can probably run around 10 FC with 360 CYA and manage to get by until a source of water can be obtained.

I normally wouldn't suggest it, and it is uncharted territory no question. In my opinion it is the least bad option, since a 30 FC level would hinder pH readings and burn through reagents very quickly. This plan will allow some leeway to be able to get accurate pH readings. I do like your idea, jblizzle, of maintaining the FC a bit above 10 and letting it drop occasionally to get a pH reading.
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Having taken the above comment into consideration, I drained the pool 8 inches ( 19x33x 4.5ft), and the catch basin for negative edge holds 760 gal(using the pool calculator) it was empty. Refilled with fresh water. Should I run pump over night to circulate?? Will add weekly dose of polyquat. Keep FC 5. Is pool safe to swim. Water is clear now. If no rain, drain 8 in next month?
 

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The water changes will help, even if only monthly. If I did the math correctly then that is about 4000 gallons? If so that is a little over 1/5 and should have taken your CYA down to just under 300. A long way to go but progress to be sure!

Run the pump however you normally do, run tests for everything but CYA tomorrow and adjust anything that needs it. You won't need to do another CYA test until you have done another water change or two. For now you can leave it as "very high". It is safe to swim in as long as your water is clear and you have FC. If you can only do 8 inches a month then you should do that, even if you get rain. So pencil it in for next month and watch the forecast to take advantage of any rain you can.

You are heading in the right direction, in a few months you should be able to ditch the polyquat and stick to chlorine. Better all around for your pool. Good luck!
 
The general consensus is that is is safe to swim at any FC below your shock/SLAM level for your CYA.

So, if your SLAM FC target is 20FC, any level below 20 is fine. The CYA removes much of the harshness of chlorine.

WOW... i forget which thread this was... 120? I guess it really shows you the effects of CYA.
 
Donldson said:
For a CYA of 300, roughly 120 ppm.
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:shock: :lol:

EDIT: Technically, we also usually say it is safe when the FC > minimum for your CYA level as well to protect swimmers from nasties in the water. For CYA of 300ppm, that would be a minimum FC of 23ppm. So, is it "safe" at 5ppm? Depends on what nasties are in the water.
 
Yes, the Polyquat does actually inhibit the growth of some pathogens as well, but not fast enough to be considered a swimming pool disinfectant. Fecal bacteria will still be killed much faster than they can grow so you are unlikely to get uncontrolled bacterial growth in the pool. At 10 ppm FC with 300 ppm CYA, this has the same active chlorine level as 0.026 ppm FC with no CYA except that at this FC level the chlorine bound to CYA can't be considered to be completely inert.

So kill times will be no slower than taking those in the table in this post and multiplying by 4 (approximately). So 99.9% of fecal bacteria are still killed in under 5 minutes (half killed every 30 seconds).
 
Given your pool's dimensions of 19' X 33' every inch of water you drain will remove ~391 gallons. An 8" drain would be ~3127 gallons, which is ~17.4% of your 18k gallon volume. If your CYA level was 360 based on your 1:3 dilution test (90 x 4) then it would take 9 drain/refills to get down to CYA of ~64 if you stick with 8" each time.

You've did your first drain already but IF you could possibly bump the amount you drain each time up to 12" going forward (~4690 gals) you'd move to about 26% per drain and that would only take 5 more drain/refills to get your CYA to ~65. I'm not sure how the catch basin you mentioned works in your pool relating to draining but if the 760 gallons you calculated it holds is in addition to the amount you're draining from inside the pool you'll be able to get to a more manageable CYA level even quicker.
 
I'm not sure how the catch basin you mentioned works in your pool relating to draining but if the 760 gallons you calculated it holds is in addition to the amount you're draining from inside the pool you'll be able to get to a more manageable CYA level even quicker.
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Yes, that is in addition to the pool level--the negative edge flows over into the catch basin. It is 17 ft x 2 ft 3 feet deep
 
Depends what CYA you are starting with. If 300ppm, then you need to replace around 85% to get to the recommended range.

Pretty sure this was discussed before.

Of course if your ground water is high, you may not want to drain the pool too far or it could float out of the ground.
 

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