Changing from Cl dosing to Cl generation from salt.

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RonPace
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Re: Changing from Cl dosing to Cl generation from salt.

Postby RonPace » Wed 01 Sep, 2021 09:13

I spoke with a neighbour of mine who manages his pool well- if the clarity of water is anything to go by. I told him my planned changes when he offered to bring his tester over and measure things which was pretty decent of him. He has a little blue thing called a SCUBA and several foils of tablets.

He came up with Free Chlorine of 3.3 and Total Chlorine of 4.5. He reckoned my combined chlorine is a bit high (?) and rattled off the science of it all.
Ph is 7.6 which he said could come down a smidgen (He is Dutch!)
Alkalinity is 72 which he said is ok.
Now he says CYA is 53 - this despite my paranoia of not using chlorine tablets or stabiliser! So how has this happened?
His tester did not measure calcium.

I plan to empty sacs of salt into the pool and fire up the generator this weekend.


Denniswiseman
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Denniswiseman » Wed 01 Sep, 2021 09:48

If you have a CC 1.2 you need to Slam (Shock Level and Maintain) with relation to Chlorine / CYA Chart and Recommended Pool Levels

Before adding salt get some Liquid chlorine (sodium hypochlorite or plain bleach) to Slam
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Wed 01 Sep, 2021 10:41

As Dennis said.
Dont worry about pH yet as it doesn't matter much so long as there is sufficient chlorine to CYA, the idea that pH should be between 7.2 and 7.6 is old news and doesnt really apply to outdoor pools with CYA in them. pH is more important in indoor pools without CYA.
Good luck for the weekend!
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Wed 01 Sep, 2021 10:45

That Scuba is an old unit, used to sell lots of them and quite good provided the O ring doesn't fail. New tester out probably next season now featuring Bluetooth tech or the Scuba 11.
RonPace
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My Pool: Uncovered inground 12x6M, Cl and Ph solenoid doser. Glass media filter. South France

Re: Changing from Cl dosing to Cl generation from salt.

Postby RonPace » Sat 04 Sep, 2021 04:23

Thanks Dennis - I have emptied a shedload of liquid chlorine in. The first load got me to 0.4 difference. Had some left over, so threw this in and now I am according to my neighbour pretty well the same, his meter showed the same reading for free and total, then a 0.1 difference after a few pressings of the button. So I am using this as a green light to empty the salt in, stir it around and maybe switch on the chlorinator tomorrow...

Two more questions if not a nuisance please:

1. How much will salt on its own kill algae? I am wondering how good it would all be if one were away and the electricity tripped, how long would the pool stay clear on its own? With a doser and liquid chlorine, I know (from experience) that algae starts a few days after a power failure.

2. Can one over salt a pool with a chlorinator? I am not worried about side effects to swimmers but more the technical side. Example would be where a swcg asked for 3500 salt, but knowing one would be away for a long time, raised the level to say 5000 or 6000 to provide a buffer of salt for the swcg?
Denniswiseman
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Denniswiseman » Sat 04 Sep, 2021 05:20

Salt won't kill algae, but a solid cover will prevent (block sunlight)
You don't need to over salt as the salt doesn't get used, you only lose it with backwasing and splashout
Best to stick to the manufacturers recommended levels
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Sat 04 Sep, 2021 06:10

Youll need dead sea levels of salt to prevent algae, there is lots of algae in the sea. If the pool turns green after a couple of days without power then the water is probably quite nutrient high, test for phosphate, its caffine for algae! Little or no phosphate, little or no algae, no food you see. Several phosphate removers around, they can make the water cloudy for a while afterwards but not always, depends on how much phosphate to start with.
RonPace
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Re: Changing from Cl dosing to Cl generation from salt.

Postby RonPace » Sat 04 Sep, 2021 22:53

Makes eminent sense what you say. I never thought of it this way, but when I think of it, its no different to basic gardening! Thanks!

So, another thing to test for. I google it and there are phospate test strips for pools. This of course leads onto, or back to subject of water testing. You suggested a good tester earlier and not strips.

Noting this the last few visits to pool shops, I see only rows of bottles of strips. Indeed, Many, including me, dutifully take a water sample to these shops who are meant to be experts, and they pull out a strip, test and sell us a container of some anti-this-or-that product. I never get a note of any numbers that you quote! But reading what you and Dennis (being the two prolific responders here) I look on the internet and see these testers, and reading a few back threads see that the Taylor is the one to have. But Taylor seems to be exclusive to the US and Australia. Here it seems to be strips, strips or strips or move up a notch and spend hundreds and hundreds of Euros for a professional chemist’s kit.

Again reading your responses and various references, I am seeing the need for accuracy against the theory - especially on the ‘slam’ and relationship of the three chlorine types. But where does stop?!

I understand my neighbours instrument and may well buy one as it claims to be all a pool enthusiast needs. But listening to you, it is not! Yes, it has Total and Free Cl, TA that you say is not a huge player, Ph which can fluctuate without harm, and CYA that is hugely important. But it does not test for salt or calcium or, now, Phosphate! So where are these kits that a conciensous pool owner should have? What you say does make sense, but it is just not catered for by any manufacturer!

And here is another one! I am still looking at the UV hydroxyl radical idea that you rate and will maybe go there as I love new tech on everything except electric cars, but how will one measure the effectiveness of UV doing its job? With my soon to be swcg or doser it is simple - TC minus FC = <0.5. But if UV does not use chlorine, what is to say it is doing its job and one is not going to wake uo to a green pool?
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Sun 05 Sep, 2021 13:18

Just arrived at the French home, need some good sleep and will answer tomorrow. If you can wait a bit the newest revamped model of tester will be available soon, probably in time for next year though.
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Mon 06 Sep, 2021 04:30

Hi Ron,
Yes despite the huge number of pools in france decent test kits are just not around, its why I have sold so many over the years and not for profit just to cure the pool shop issues you highlight, "oh sir you need this this and a packet of this, see you next week"

As it is close to the end of the season see if you can keep using your neighbours Scuba, as I said there are no units available of the electronic tester I usually supply. I can supply Scubas but IMO they are not as good as Color Q pros. Now testers, the more they test for the higher the price. My pro unit can test for just about anything you can put into water, subject to the purchase of the reagent. My unit cost £800 and about £150 to recalibrate. The main tests are all you really need any additions can be stand alone tests for cheapness but I haven't used a test strip for phosphate as I use a liquid reagent test. The upgraded Bluetooth app enabled tester with calcium level will be out soon.
With UV its the dose and exposure time that treats the water, another reason for a slower pump. Its really down to getting used to you pool, I would expect to see the chlorine level rising a bit when UV is doing its job as the chlorine will last longer with less to do. The clarity of the water is where you would see the biggest difference. I can test that with my nephelometer which shows the clarity of the water. Big difference between sand and AFM, big difference between people who only filter the pool for short periods over 24 hour filtration. Clarity of my pool is just above tap water usually, when I change to AFM ng next season it really should be equal or better than tap water. The less work the salt cell has to do the longer it will last. As they are not cheap that is a point.
Denniswiseman
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Denniswiseman » Mon 06 Sep, 2021 11:43

It maybe worth while checking what the import cost of a Taylor K2006C from the states is
Teapot1
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Re: Changing from Cl dosing to Cl generation from salt.

Postby Teapot1 » Mon 06 Sep, 2021 16:11

Yes always, and add in 140 test reagents to get a level playing field. Its the reason I recommend as I do, the Scuba looks a good deal until you add in the number of tests. In the case of US imports also thay3you can continue to get reagents as a few years back certain ones were banned from shipping.

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