Numbers post partial drain and refill...

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#1
:(

Here are the results from my first complete test

Temp. 72
FC 7.5
CC 0.5
pH 7.7
CYA 100 +
TA 220
CH 500

the water is clear but I guess the prolonged "tablet" use has taken its toll..
will get some distilled water and redo the CYA and CH to get a better picture..
 

Buggsw

LifeTime Supporter
Apr 22, 2007
925
Arizona
#2
Hi!

Yes, the tablets and pool store shock create some problems with too high of a CYA.

Your CC's are at .5 you really need to add chlorine at a high enough level to get rid of them. With your CYA you need to shock quite high.

You should probably switch to liquid chlorine/bleach.

Your TA is quite high, as well. Use Muriatic acid to bring it down. Add enough to bring your pH down to 7.0, which will also lower your TA. Then aerate to bring your pH back up and repeat with the muriatic acid.

Consider draining some of your water to reduce your CYA.
 

JasonLion

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May 7, 2007
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Silver Spring, MD
#3
I wouldn't worry about CC at 0.5 or lower.

The big issue is the CYA. The common CYA test will show anything above 100 as 100, so it could be quite high. Assuming that CYA is 150 you need to keep FC at 12 to keep algae away. It would be best to replace some water to try and get CYA below 100. Depending on your fill water, that might also help with your TA and CH, which are both high.
 

duraleigh

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#4
Saraiks,

Your self-diagnosis is pretty good. The tabs have gotten your CYA up there where managing your water can be difficult. (although it seems like you're doing pretty well with clear pool water and an FC of 7.5)

Draining some out and refilling may be a pain now but probably beneficial in a number of ways for the future. It should also help reduce your CH......not a bad idea, either. BTW, have you been using Calcium Hypochlorite either to shock or for some of your FC? That would explain the high CH.

As Jason said, the CYA is your biggest issue.......requiring even more FC than you currently have. A 50% drain and refill may get all of your numbers back into a more manageable category.

CC's of .5 or less are pretty common in many pools.....it's typically when they get to 1.0 or more that you need to pay attention.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#5
I agree that a partial drain and refill is the first step. The gallons of clorox were the first item to be picked up yesterday.

Question: Will diluting with distilled water give a good CYA reading ?
 

duraleigh

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#6
Question: Will diluting with distilled water give a good CYA reading ?
Well, it certainly will add variance to a test that is already a little imprecise to begin with. So, if the CYA test can vary by 10-15% (that's just a guess) anyway, when you dilute by half, your error margin could be pretty big.

I still think it's probably worth a try. It would at least give you a better indication of where you really are.

Unless you already have it on hand, I see no real need to use distilled water. Your testing for turbidity (cloudiness) and good ole' tap water will probably give you the same result.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#8
Latest Results..

Did another set of tests last night and here are the numbers. Found out the well known fact that FAS-DPD is the way to go.. the ordinary chlorine test was realy not giving the true picture...

FC : 29 (FAS-DPD and yes I counted all of the **** 58 drops it took to do it....)
CC : 0 (FAS-DPD)
CYA 100 + (need to redo with a 1:1 dilution to get a ballpark number)
pH : 7.6
TA : 180 (was 210. Reduced pH to 7.2 with acid and aereated the pool to bring it back up as advised)
CH : 500 (not retested)

Question: Do you guys see any issues with running such a high FC even though the CYA for all practical purposes may be way up there ?
 

JasonLion

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#9
High FC is needed when CYA is high. You have FC at shock level for a CYA of 130. That isn't going to hurt anything, but there is no need to keep it that high. I would let it drift down a little, say to 20, while you figure out what your CYA level really is.

I suggest doing another round of acid and aeration to bring the TA down another step.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#10
I finally managed to do a CYA test with a 1:2 dilution. The result was a CYA of 70. Which means my actual CYA is close to 200. This explain a lot of things though. The FC level is very high because hardly any was lost due to the high CYA. The previous owners just had tablets in the skimmer all the time which kept it way up there. They did occasionally shock it with a Calcium based pool shock from Leslies which raised the CH to the high level it is.

I will go ahead and do another round of Acid and aeration as suggested to get the TA a bit lower. The partial drain and fill is next on the list after that.

Question: Is there any chemical method of reducing the CYA ??
 

duraleigh

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#11
I think there's one available at pool stores. Reports have been it's effectiveness is pretty weak (you need a ton of it) and it's prohibitively expensive. I believe you will find a 50% drain and refill (followed by another 50% drain and refill) is your best bet to have manageable pool water.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#12
A drain and refill is not an easy option for the way my pool is plumbed. There is no Vaccum to waste possible. I might be able to siphon off a little and will have to pump out the rest.
 

JasonLion

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#13
Do you have an overflow drain? If so you can simply add water at the other end of the pool and let the overflow drain keep the level from going up too high.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#14
I think I do have an overflow drain as I saw a small(3/8 ?) pipe hole sitting above the water lie. I was thinking of more like jerry rigging a hose to one of the jets and out to the kerb...!
 

divnkd101

LifeTime Supporter
#15
Also check around your pump. You may have a regular water spiggot (attached to pool plumbing) to attach that hose to. I do have an overflow in my pool but when heavy rains come, I tend to open the spiggot as well and drain to the curb. Good luck.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#16
I did find a spigot right next to the filter which is primarily used to drain the filter of all water before opening it up for cleaning. This has been attached to a plastic pipe with a flex connect fitting. This pipe drains directly to the kerb. I used it to drain the pool of about 3 inches of water. The Butterfly Valve in my skimmer is not working properly because as soon as the water level dropped below the weir door it started sucking in Air evethough the butterfly valve was fully closed. Assuming an avarage depth of 4 feet that is about 1/16th of the water. I intend to repeat this process again for the next few days to see if I can further lower the numbers into manageable range.
 

sammm

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May 10, 2007
257
North Richland Hills, TX
#17
saraiks said:
I used it to drain the pool of about 3 inches of water.
I went thru the high CYA issue when we bought our house a little over a year ago. If your CYA is at 100 (or wherever), you will have to drain 1/2 of your water and refill with fresh water to cut that number in half. If it's 150, draining 1/2 the pool will drop it to 75. Painful, I know.
 

duraleigh

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#19
If you're looking for comments, I think you're gonna' have to do a major drain (50%) on your pool to get your CYA manageable. You may, in fact have to do it twice. I know it's a PITA, but your life will be much simpler.
 

saraiks

LifeTime Supporter
Jul 23, 2007
74
Fremont, CA
#20
A major drain is a PITA with the setup I have. I was planning to do a partial drain and fill of about 5% to 10% everyday for the next few weeks and see if that works. If not I'll rent a sump pump from somewhere and go for the major PITA.

But you are right about life being easier after the drain and I am looking forward to it..