Changing from Cl dosing to Cl generation from salt.

[RonPace]

Hello! My first post and hope here is as good as any of the chat rooms.

Introduction: I have a 12x6M ingound pool that I leave uncovered all year (covered pools look very sad to me!). I use a solenoid doser for both Cl (basic supermarket 9.6%) and Ph. I am maybe a little lazy in keeping other levels in total check, but I seem to manage to keep on top of things!

Now. Big problem - water table here is VERY high. As a result, I am paranoid on the CYA becoming too high. This of course brings another issue in that I am maybe using too much chlorine, but it is the price I must pay to assuage my paranoia!

Last, the pool is not used much for most of the year, but come July, August and September it reverts and sees a lot of use. This is not an issue as it is easy to up the dosage and keep a plentiful supply of Cl. Ph behaves itself without much manual intervention.

I have an idea, but here I need a sounding board in the form of an old hand willing to share sanitising info.

I have in mind to make the pool a saltwater type with a quality self cleaning all singing dancing generator set to a level low enough to keep the pool clear. I plan to keep my EWT doser for the Ph, and come July for three months switch on the Chlorine pump to raise the chlorine level to satisfy the increased use that a chlorine generator cannot cope with. My questions thus are:

1. I take it that there is no issues for a 12x6 pool to be 'salt water'?
2. What type of chlorine generator is required for such a pool size?
3. Is the retention of the Cl dosing pump a good idea?
4. Can you dose a 'salt water' pool with liquid chlorine to suddenly raise Cl levels without any trouble?
5. Will a chlorine generator struggle if the CYA level is on the low side?
6. Would the addition of a UV tube array help?

If anyone wishes to shoot my idea down in flames, I am happy to listen! I hope not though, as I have to admit that the novelty of lugging 20 litre cans of chlorine around has worn off long ago!

Thanks for any help!

[Denniswiseman]

1. I take it that there is no issues for a 12x6 pool to be 'salt water'?
None at all

2. What type of chlorine generator is required for such a pool size?
Get one that is rated twice the size (litres)for your pool as they are rated 24/7

3. Is the retention of the Cl dosing pump a good idea?
No problem. Could be used if you have problems with your SWCG or to add CYA
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
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
To reduce your CYA you have to do a partial drain and refill
Continuous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well

4. Can you dose a 'salt water' pool with liquid chlorine to suddenly raise Cl levels without any trouble?
Yes

5. Will a chlorine generator struggle if the CYA level is on the low side?
A SWCG pool needs about 80ppm of CYA whereas a liquid chlorine needs about 45ppm as indicated in Chlorine / CYA Chart

6. Would the addition of a UV tube array help?
I have no knowledge

I would be inclined to get a cover that blocks out light to keep it algae free when not being used
High water table isn't a problem with a partial drain and refill providing you don't go well below the water table

[Teapot1]

As Dennis said, get a pool cover, you can leave a winter cover on all year, saves water, saves chemicals, saves time and of course money.
I am finally getting over to France next week after a year and 2 months. The cover is still on and BIL reports water is still clear. That's what doing it right rewards me with.
Regarding salt chlorination, if your pool is part of a rental setup in France you should not use salt chlorination as its not allowed.
Is your pool vinyl or GRP?

[RonPace]

The pool is vinyl and in pretty good condition (I am told). It is a private pool.

You are kindly helping me on another thread - I wonder if these should be combined?

[Teapot1]

Hi Ron,
OK, as the pool is vinyl you can change the water parameters from what is written. High Total alkalinity causes pH rises, salt chlorine generators cause pH rises. Reducing you Total Alkalinity will vastly slow down any pH rises with no ill effects, the 120ppm you see written down really applies to plaster and tiled pools to protect the surfaces from erosion, no such problems occur with plastic pools.
Do you know the levels of you water? Hardness, Total alkalinity, pH etc, in short do you have a good test kit and not just dip strips?

[RonPace]

Dennis - you mentioned specifically above that a generator should be spec'd for 24/7. I was out yesterday looking at some, but none gave such specification. Some related production of gr/hour with some showing pool size, and even then they were confusing with some being 'professional' and others 'easy to use'. then there are the number of producers - where does one begin? I must admit that the most helpful were those in Cash Piscines selling a range branded 'Racer' and another 'Dexton' - both 'made' in France. They offered me a good deal on one that was 19gr/h.

Another place had Zodiacs. these were even harder to follow, there were so many! But one did satand out - an El-25 rated for 100M3.

Help!

[Teapot1]

Racer and Dexton are Cash Piscines own brands, the ones at 19grms are a bit on the small side for your pool.
Ask them about spares, Not sure they are actually manufactured in France, more like China but the final parts maybe added in France.
That said most manufacturers do this these days, there is a good company in Kent and they use mostly German parts.
If all the components of your pool work harmoniously as described in the other thread the chlorinator will have an easy and long life. As an experiment years back after adding the variable speed pump, the AFM glass and vastly improving the plumbing, I ran my pool on 0.2-0.5ppm of chlorine for several seasons, not bad for an outdoor pool in rural France.

[RonPace]

'morning Teapot

In the absence of any firm recommendations, this morning I purchased a Zodiac Ei-25 that claims to be the one for a pool my size. The decision was made on the proliferation of Zodiac in the area and as you once said they are underwritten by Fluidera who are also prolific with their other products here. I am also taken by the simple installation.

I have a mini pallet of salt arriving soon and shall set about making the change to salt, but with my doser as back-up (here I am annoyed as it seems that I cannot have just the Ph dosing without the Cl dosing. The manufacturers tell me to set the Cl pump really high with solves the issue...).

I shall continue to look at the UV option, but maybe do all this in stages - one, then another, rather than jump in. The Zodiac has four chlorinating levels, one being a 'cover' level that the sales chappie said would be ideal for when I introduce UV.

[Teapot1]

Great and 25grm should be sufficient.
To lessen the pH rise work on lowering your TA to around 50ppm. When I worked in Jumilac le Grand their water TA was only 27 and the had to add pH up, nothing bad ever happened so thats when I began experimenting with TA, built a test rig and tried lots of samples. I run my pool around 45-50 and haven't added a drop of pH- in 4 years! TA of 80-120ppm for concrete and tiled plaster etc and they have to put up with rising pH. That means you wont need pH dosing which is safer, manual if needed but on another Dordogne pool this chaps test probe played up and he dump 20ltrs of hydrochloric acid in his pool.

[RonPace]

How can you get the detail so accurate? You asked once if I have a test kit. No, I do not! Sounds a bit technical to me. I rely on the Cl and Ph readout on my doser, and I use a the Aquacheck strips that shows me pretty well were it is at. What sort od test kit are you talking about?

I guess I shall now need a salt checker that seems important - how about one of these: https://www.poolplanet.com/fr/testeurs- ... gJX0fD_BwE ?

[Teapot1]

Hi Ron, salt levels are not that important +- 500ppm wont matter so test strips are ok for that. Otherwise I would say you are pretty brave relying on your probes, It is normal to recalibrate probes twice a year but certainly at the start of each season. Test strips for other parameters are just guess strips. Whilst some things may not be as important CYA and Chlorine really are, neither are accurately measured with strips. You may get a colour change but they are pretty meaningless.
About £140 buys you an accurate digital tester with around 140 test reagents so lasting about 5 years before needing more reagents. There are other test kits around for a bit less.

[RonPace]

How about a test kit that shows how much chemicl is actually required? Does anyone make something along these lines?

Without anything concrete to go on, a quick google shows the Poolmaster 5-Way Test Kit to be the best - correct? It looks to be a lot like an old simple Cl/Ph one I used before the doser was installed, but bigger.

The shop gave me a bottle of strips for the salt and calculated how many bags I would need to get up to a basic level.

[RonPace]

Well, it cannot be that great - it does not measure CYA. Even I know this is important! Crazy google.

How about one from taylor, the 2005C - SALT, it seems to do everything including salt and looks straight forward to use.

I am surprised not to find someone who makes a test box that one can link to a PC that determines how much chemical one needs. It seems quite a simple thing to do in programming I would have thought...

[Teapot1]

Ron there is often a issue shipping liquid reagents and especially from the USA. That said you are correct any kit not measuring CYA but claiming to be the best is clearly marketing hype.
There are testers that have apps and link to calculated tables but do you need that?
All you need is here and free https://www.troublefreepool.com/calc.html.
That said please listen to me about TA and hardness which are not important in plastic vinyl pools.

[RonPace]

Yep, that is quite cool and what could be useful!
thanks, I shall bookmark it definitely, and maybe get myself more into the detail of the pool!