Need to check my readings don't matter.

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
TimboZero
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My Pool: 42,000 Liter (8m x 4m) coffer and liner construction with 'All in One' pump/filter unit.
Location: France

Need to check my readings don't matter.

Postby TimboZero » Tue 23 May, 2017 08:17

Good day all,

I just wanted to check a few things that I believe to be true but confirmation never hurts.

If my TC and FC are the same then I am good and there is no need to shock to burn off chloromides correct ?

My TA and TH are both rather low (40 and 500 respectively) but I don't struggle with pH or anything else for that matter, so neither of these measurements matter ?

Many thanks for the help
Timbo


Denniswiseman
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Re: Need to check my readings don't matter.

Postby Denniswiseman » Tue 23 May, 2017 09:53

You don't mention Cyanuric acid (stabilisor) as this has an effect on your chlorine
Please give all your numbers

FC:
TC:
pH:
TA:
CH:
CYA:
My pool construction:
Pool chemicals used:
Filter:
TimboZero
Pool Newbie
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Posts: 9
Joined: Sat 23 Jul, 2011 00:41
My Pool: 42,000 Liter (8m x 4m) coffer and liner construction with 'All in One' pump/filter unit.
Location: France

Re: Need to check my readings don't matter.

Postby TimboZero » Tue 23 May, 2017 11:15

Thanks for the reply, I tend to not keep a particularly high CYA as I had a pool that was 'CYA locked' a few years ago and needed a partial draining.


Please give all your numbers

FC: 5-10
TC:5-10
Currently settling back down after shock
pH:7.2-7.4
TA:40
CH: <100 (hardness ?)
CYA:<30
My pool construction:vinyl liner in coffer (in ground)
Pool chemicals used: di and tri chlor
Filter: it's a Desjoyaux pool, need I say more. Basically a 6 or 15 micron 'sock'

I am not worried really about chlorine, or pH, as they have been always easy to maintain.
I am however told that combined chlorine is the bubble killer (summer cover) so wanted to check that FC and TC should be the same number +\-1or2?
What 'worried me' was I got new test stick (Aquachek) that show alkalinity and hardness and both are really low.
Denniswiseman
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Re: Need to check my readings don't matter.

Postby Denniswiseman » Tue 23 May, 2017 17:15

I understand about CYA but the fact that you are using dichlor and trichlor will definately raise your CYA. You would be better off using liquid chlorine
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
Your FC and TC range of 5-10 could be way off and you can't accurately check for CC ( your total could be 10 and your free 5)
Combined chlorine is removed by doing a Slam in conjunction with Chlorine / CYA Chart also a good check for correct Pool Levels for your type of pool
So long as you keep a stable pH you don't have to worry to much about TA although it seems quiet low
CH is fine with a vinyl liner
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
One other thing is you need to get a decent FAS/DPD test kit to get more accurate numbers as they are very important to get your chemistry correct
TimboZero
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Posts: 9
Joined: Sat 23 Jul, 2011 00:41
My Pool: 42,000 Liter (8m x 4m) coffer and liner construction with 'All in One' pump/filter unit.
Location: France

Re: Need to check my readings don't matter.

Postby TimboZero » Wed 24 May, 2017 03:17

I understand your comments. My testing method (Aquachek strips) is far more accurate at lower levels but under shock conditions they are only indicative.
CYA shouldn't be too much of an issue, I tend to slam with LC and annual CYA levels never exceed 60 (rarely breaking 50).
Once I am down to usage chlorine levels (say 3ppm FC) and TC is also between 3-4ppm I am ok?

With the TA, would you bother to give it a bicarb dose? I don't tend to suffer with pH issues but I am assuming unused pool pH would be a lot more 'locked in' with higher TA?
Denniswiseman
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Re: Need to check my readings don't matter.

Postby Denniswiseman » Wed 24 May, 2017 06:11

I must emphasise that Strips are widely inaccurate. I used to use an Aquachek TruTest meter untill I compared it with my Taylor K2006C Test kit (way out)
The fact that you are using dichlor and trichlor will definately raise your CYA which will in turn affect your Chlorine / CYA value
CYA of 50/60 is OK if you can trust your testing
A high TA can cause your pH to rise
Did you read the links I included as they give a better understanding of the Trouble Free Pool method
TimboZero
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Posts: 9
Joined: Sat 23 Jul, 2011 00:41
My Pool: 42,000 Liter (8m x 4m) coffer and liner construction with 'All in One' pump/filter unit.
Location: France

Re: Need to check my readings don't matter.

Postby TimboZero » Wed 24 May, 2017 06:52

I also had the TruTest a while back, it is awful I agree. The AquaChek yellows I use give me same results as I get from a DPD test and I find them easier to read.
Yep, read the links and played about on poolcalculator as well. Looks like to get my pool up to the suggested 100TA would need nearly 4kg of bicarbonate which is going to impact pH a fair bit. Think I will halt aeration and use bicarbonate for my pH+ for a while until TA rises a bit.
Denniswiseman
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Posts: 777
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Need to check my readings don't matter.

Postby Denniswiseman » Wed 24 May, 2017 16:04

Bicarbonate will only raise your TA but a high TA can raise your pH slightly as does aeration
TimboZero
Pool Newbie
Pool Newbie
Posts: 9
Joined: Sat 23 Jul, 2011 00:41
My Pool: 42,000 Liter (8m x 4m) coffer and liner construction with 'All in One' pump/filter unit.
Location: France

Re: Need to check my readings don't matter.

Postby TimboZero » Thu 25 May, 2017 01:54

Ah that is great news, for some reason I thought bicarbonate would raise pH as well.
Will push TA up a little just to have it in spec, might make pH more stable (never noticed a problem but then it might reduce pH+\- costs that I didn't realize were higher than needed)
Thanks Dennis, really appreciate your time on this.
Denniswiseman
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 777
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: Need to check my readings don't matter.

Postby Denniswiseman » Thu 25 May, 2017 11:00

You're welcome, if we can get people to care for their pool by understanding the simple chemistry at the minimum expense and keeping them out of the pool store, it makes my day as well

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