Chemical balance confusion

[BluegrassFreak]

Having read lots of the advice in this forum regarding various chemical levels, and having for the past 3 years used the simple 5 drop tester for PH and Chlorine, I decided to become a little more precise in my attempts to get the chemical levels of the pool correct. I therefore invested in the AquaCheck Truetest electronic tester with strip readers.

I have a sand filter system and the the pool is about 45 cubic meters (10,000 gallons).

In my most recent test with the old 5 drop tester, it indicated that the chlorine was about 1 to 2ppm and the PH around 8 (difficult to judge exactly what story the colours tell !)

In my first test with the AquaCheck it indicated that I had 0.00 chlorine, 7.2 PH and 162 Alkilinity.

Obviously the chorine has to be adjusted. The PH seems to be within acceptable levels, but the Alkilinity is way out of tolerance. The documentation recommends that I put 3.6 to 4Kgs of Sodium Bisulfate to correct the Alk. What is Sodium Bisulfate? where can I buy it? and will it have an effect on the chlorine and PH readings? If so how should I compensate for the changes that may be caused by the Sodium Bisulfate ?

I note that Javel is often recommended rather than the multifunction chlorine tablets that I normally use. What is the dosage of Javel needed when the pool has a 0.00 reading of chlorine ?

I also noted that reference is often made to the cyanuric acid reading. This is not catered for with the AquaCheck tester. Is there any other way I can check the level of cyanuric acid ?

This is also the case for the Bromine reading. How do I check this level? (although in the documention it does say to multiply the chlorine value by 2.2, but it does not say how to adjust the Bromine level if it is incorrect)

The other thing that puzzles me is that I follow precisely the instructions for closing the pool down for winter with ant alge etc, but every year I open it it looks like a duck pond (or cesspit) with the whole pool covered in dark green algae. I'm told locally that this is because the pool was too high in chlorine before I closed it, but I always check the levels are correct before I close it (with my 5 drop tester that is !)

Many thanks in advance for any advice you can give

John

[Poolguy]

Well John there is nearly nothing there that I can agree with.

Aquacheck is not much better than the drop test which is actually testing the wrong value (total chlor) you need Free Chlor

If the levels are to be believed then your pH is fine, nothing to do, you TAC (162 I don't beleive it) is fine nothing to do.

Sodium bisulphate is pH minus, do not add any. TAC is raised with Bi carbonate Soda - you do not need any.

Javel is Liquid chlorine add enough to get 1.5 - 2ppm, how much depends on the needs of the pool, only testing will tell you when its enough. Start with 2 litres per day.

If you want to winterise successfully then don't expect antialgea to do anyhting for you, its not meant for that, the advise you got 'locally ' is completly WRONG, don't ask them anything else.

The only thing able to keep algea away is the presence of chlorine/bromine.

I think that you need some professonal assistance to clear up your pool management procedures.

Don't use the drops anymore, to get Cyanuric acid you need to purchase a test that will give you the facility; Aquacheck doesn't do it but Scuba + does.

Andrew

[BluegrassFreak]

Hello Andrew,

                      Thanks for your reply. To say I was flabbergasted by it is a classic understatement! And there was me thinking I was upgrading my expertise with the purchase of the Aquacheck. I'm 80 Euros lighter and it seems back to square 1.

Before reading your reply I had added more chlorine tablets and PH minus into the water, and now get a reading (with Aquacheck of course) of PH 7.2,  Chlore 0.00 and Alk 158 which seems reasonably consistent (accepting that it is all wrong!)

I accept your expertise in your assessment of the Aquacheck, but am surprised that it is so useless as it's made in the USA where they probably have more pools than anywhere else in the world and would expect them to have a good product to cater for them?

Anyroad up, ~Taking your advice to do nothing leaves me non-plussed as I now have no reliable method of checking the chemical quality of the pool. I visited your website to check on the Testers"Cool Pool" (Palin), and Scuba/+. Clicking on the shopping Tab on your site does not open the page so I was unable to check the price of these products. (not that I'm in a hurry to lighten my wallet again so quickly) Is it your advice that the only way I can proceed is to abandon the Aquacheck (say, jumping on it with my hobnailed boots), and invest in Cool Pool or Scuba+ ? If the 5 drop and Aquacheck are so unreliable, then I need to have a a reliable method of testing to get my pool up to a good and consistent quality (which I suppose answers my own question !).

I also noted in the Forum that you recommend changing the sand in the filter for Zeolite ? I would consider doing this but do not have the expertise to do this myself. Do you travel to carry out this kind of work and get pools into good chemical condition?

I'm in the Aude South of Narbonne and assume that such a visit would be quite expensive ?

Look forward to reading your comments, although they may casue me some sleepless nights (kidding).

Many thanks,

John

[Poolguy]

I've sent you a PM

Andrew

 

[chem geek]

The USA tends to over-promote the use of stabilized chlorine products (Trichlor tabs/pucks, Dichlor powder for "shock") which leads to algae growth in many pools from a buildup of Cyanuric Acid (CYA).  I wouldn't assume that anything from the USA is necessarily better -- it's just more likely to be more profitable for manufacturers.  Product offerings are driven more by economics than what is best for the consumer.  I'm not bashing; I live in the U.S., but one can't deny the truth.

The best test kit at a reasonable price is the Taylor K-2006 which in the U.S. can be obtained online [url=http://www.amatoind.com/taylor-k2006-test-p-555.html]here[/url].  It tests for Free Chlorine (FC) and Combined Chlorine (CC) using a FAS-DPD chlorine test where you count the drops until the sample turns from pink to clear as shown in the demo [url=http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=11]here[/url].  It does not bleach out and can measure up to 50 ppm and can be accurate to within 0.2 ppm when using a 25 ml sample size (0.5 ppm when using a 10 ml sample size).  It also tests for pH, Total Alkalinity (TA), Calcium Hardness (CH) and Cyanuric Acid (CYA) generally with 10 ppm accuracy (CYA is a little tricky but still far better than test strips).  A similar alternative is the TF-100 kit from [url=http://tftestkits.net/Test-Kits-c4/]tftestkits.net[/url].

Test strips, even those used by your AquaChek meter, cannot test for Calcium Hardness.  They only test for Total Hardness which is pretty much totally useless since it is calcium and not magnesium that is needed to protect plaster surfaces from dissolving and to not get too high to prevent scaling.  The CYA test is also very often wrong when using test strips.

In Europe, the closest test kit to the Taylor K-2006 that I've been able to find is the Palintest Pooltester SP 315C that does all of the aforementioned tests, BUT uses a DPD chlorine test.  At least in the U.S., Palintest has introduced a FAS-DPD chlorine test as described [url=http://www.palintestusa.com/products-details.aspx?id=72]here[/url].  The Palintest meters that Andrew offers are also good so you have to weigh cost vs. convenience.

[Wilko]

Poolguy

Can you fix your site so shopping works ??

W

[allanb]

[quote user="Poolguy"]Aquacheck is not much better than the drop test which is actually testing the wrong value (total chlor) you need Free Chlor

...

Don't use the drops anymore, to get Cyanuric acid you need to purchase a test that will give you the facility; Aquacheck doesn't do it but Scuba + does.[/quote]

I'm trying to convince myself that I don't really need to spend £100+ to find out what I need to know.

I have bought an Aquachek kit which uses test strips.  It really is spelled like that, without the second 'c' - I presume that we're talking about the same manufacturer: Hach Company from Elkhart, Indiana.  It cost me less than €10, IIRC.  It claims to measure 4 things: free chlorine and cyanuric acid, mentioned by Poolguy, and also pH and total alkalinity.

Now I can understand that colour strips may be less convenient and less accurate than something with a digital readout, for instance.  But does that really mean that they are useless?  Is the Hach Company lying when it says that the kit measures those four things?

Or is Aquachek something different from Aquacheck?  

I'm confused.

[Jonzjob]

I have a Scuba+ and as far as I'm concerned it is the dogs proverbials. Easy to use and, from what I believe, accurate.

It does take a little longer than using drops, but I have time for that to get the accuracy.

[POB]

Poolguy,

Could you PM me with details of the Scuba + inc delivery and necessary supplies?

Ta

[chem geek]

[quote user="allanb"]I'm trying to convince myself that I don't really need to spend £100+ to find out what I need to know.

I have bought an Aquachek kit which uses test strips.  It really is spelled like that, without the second 'c' - I presume that we're talking about the same manufacturer: Hach Company from Elkhart, Indiana.  It cost me less than €10, IIRC.  It claims to measure 4 things: free chlorine and cyanuric acid, mentioned by Poolguy, and also pH and total alkalinity.

Now I can understand that colour strips may be less convenient and less accurate than something with a digital readout, for instance.  But does that really mean that they are useless?  Is the Hach Company lying when it says that the kit measures those four things?

Or is Aquachek something different from Aquacheck?

I'm confused.[/quote]

There is a lot more than just "what it tests", but also "does it test accurately" and "to what precision".  Let's take a closer look at the [url=http://www.aquachek.com/products.asp]Aquachek® Yellow[/url] that tests for Free Chlorine, Cyanuric Acid, pH and Total Alkalinity.

The [url=http://www.taylortechnologies.com/products_kitinfo.asp?&MarketID=-1&KitID=2230]Taylor K-2006[/url] test kit uses a FAS-DPD chlorine test where you count the drops until the sample turns from pink/red to clear.  It can measure up to 50 ppm and does not bleach out at high chlorine levels (unlike test strips and DPD chlorine tests).  It can measure with a resolution AND accuracy of 0.2 ppm when using a 25 ml sample size, though usually you use a 10 ml sample size for 0.5 ppm resolution and accuracy.  The Aquachek does what?  Go ahead...take a look at the range and resolution.

The pH test is similar to a test strip (they tend to be OK with pH) though has comparator examples of 7.0, 7.2, 7.4, 7.6, 7.8, 8.0.

The Total Alkalinity (TA) test has a resolution AND accuracy of 10 ppm -- look at your test strips and see that they only roughly estimate TA -- probably only within 40 ppm.

The Cyanuric Acid test is a tricky turbidity test, but has an accuracy of around 10-15 ppm depending on where you are in the CYA scale and measures up to 100 ppm (you can measure higher with a diluted water sample).

The Taylor K-2006 also has a Calcium Hardness (CH) test that no test strip has (some test strips test for Total Hardness, but that includes Magnesium).

If you have a plaster pool or a pool with exposed grout to the water, then you really need to know the CH level and the other levels to calculate the saturation index to protect such surfaces.

The experience of thousands of pool owners at both [url=http://www.poolforum.com/pf2/index.php]The PoolForum[/url] and [url=http://www.troublefreepool.com/]Trouble Free Pool[/url] is that pool store testing and test strips are not very accurate in general, most especially for the CYA test though other tests vary a lot as well.  pH is about the only one that is usually reasonable.

Richard