Where is best to add chlorine in salt pool?

[baypond]

Hi

Quick question, if I add chlorine to a saline pool (to keep chlorine levels up during high use/hot weather). What is best option? Do I place blocks in the skimmers or add powder direct to the pool? If I use blocks (which seems better as a pre-emptive step in anticipation of high use/ hot weather) does it diminish the capacity of the poolsquad to make its own chlorine if concentration of chlorine is higher because the skimmers are in line and precede the pool sqaud chlorinator?

 

Thanks guys

 

[Poolguy]

I suggest that you add Javel (liquid chlor) directly into the pool. Not galletts (too dear)

Dilute to 25% strength in a bucket and throw it in to the centre or infront of return jets.

Keep it away from the liner.

test before and then  test again after & hour circulationto ensure the correct levels.

Adjust pH after.

Andrew

[baypond]

Thank you very much.I will follow your instructions!

 In the mean time, I have asked Pool Technologie how to adjust the PH to run at higher than the 7.0 pre-set in production. The short way is to remove the pipe from the PH-minus bottle, but I really want to find out if there is a way to reset it to 7.5.

They have actually been exceptionally quick at responding, and first want to know if the unit is actually working properly. I have to run the unit at 100% for 24hrs and then test for chlorine at the immediate inlet to the pool. I really am not sure why he needs 24hrs, and I am going to have to be pretty careful to get a reliable reading at the outlet given that the chlorine concentration must drop away very sharply within inches of the outlet. It all seems a little hit and miss.

Anyway I'll let you know... thanks agn

 

[Théière]

Baypond the PH 7.0 is probably based on the mid point 6.8 - 7.2 that most people use, why are you looking to alter it?

It is usual to test chlorine just below the surface and away from the inlet to find out how much is actually in the pool not comming out of the one place you expect to find chlorine, did they give any explanation?

[Jonzjob]

As a matter of interest.

What do you put in your PH- bottle? Sulphuric acid or something else?

[baypond]

Hi Teapot,

To recap, my problem is that I had a poolsquad 95 chlorinator installed last year which isnt coping very well with keeping chlorine levels sufficiently high when ambient temperatures are above about 25 degrees (pool 26/27) and regular useage by us and our children. We have found that there is insufficient production (even at 100%) to raise levels back up to the appropriate levels the following morning.

When I first asked about this on this forum on 31/05/2009 chem geek and poolguy suggested that 7.0 was a bit too low for good stabilisation of chlorine. I decided to ask poolsquad by email to see if it is possible to set PH higher, and they started to ask all sorts of question about the pool, I guess to find out if the poolsquad unit is working properly. The final task they have set me is to take a chlorine reading at the immediate inlet to the pool after the unit has been running 24 hours at 100%. I think that it is a bizarre and random test, but that is what they want.

One of the answers that came from the 31/05 post was that I needed to add chlorine when high pool use is anticipated, hence the question about where best to place it!

cheers

Giles

 

 

[baypond]

John,

I have no idea what is in the PH- bottle - I buy it in 20L plastic containers from pool people. Could be Gin for all I know !

[Théière]

Ah yes, I re-read original your post and now I understand.  As Chem geek and Poolguy are concerned that at a PH of 7.0 it may cause corrosion and the off gassing raising the PH, I see what you are doing now. Although if off gassing carbon dioxide then you would get a higher PH which is what you want.

Re-callibrating the unit may need to be done by poolsquad if they will do it, (insurance reasons)

The problems with chlorinators seems to be the power supplies and whether they can handle 100% production over a long period, heat is the enemy and may cause a reduction in the efficiency of the power supply hence reduction in chlorine production and presumably why they want you to carry out the test for them. Best to try,

Have you added any Cyanuric acid to stabilise the chlorine you do have?

Keep us informed.

 

 

[Jonzjob]

I would have thought that a PH of 7.2 would have been the ideal, but then again I know nowt about salt pools.

As far as the PH- is concerned it has to say on the container what is in it surely?

But what ever it is DON'T mix it with too much tonic![:-))] and for crying out loud DON't drink it 'cause whatever else it is it ain't gin!!!

[baypond]

Teapot and John,

The joys of owning a holiday home are that finding solutions to things like this get drawn out by not actually being at the property where the problem is!

I am there this weekend and will test CYN levels and chlorine levels at the outlet,  but as an interim measure add some chlorine to keep the children free of random ear infections etc!

I will look on the ph minus container for you as well as drinking a G&T......

Thanks again to all for their help

Giles

[chem geek]

Normally, a saltwater chlorine generator (SWG) pool will tend to rise in pH over time and require acid addition to keep the pH at around 7.5 which is the average pH of human tears (though anything from 7.2 to 7.8 is usually OK).  The rise is due to a combination of carbon dioxide outgassing and some undissolved chlorine gas outgassing.  Though it is certainly possible that your SWG unit is malfunctioning or undersized for the size of your pool, there are other possibilities.  First, is that your Free Chlorine (FC) level may be too low for your Cyanuric Acid (CYA) level.  In an SWG pool, the FC target minimum should be at least 4.5% of the CYA level.  Otherwise, green algae can grow faster than chlorine can kill it and initially this may appear as an unusual chlorine demand (i.e. the algae is not yet visible, yet it is hard to maintain an FC level).  Second, is that your CYA level may be too low in which case your FC is dropping too much each day from the UV rays in sunlight.

You can easily distinguish between these two scenarios by doing an overnight test to see the drop in FC from after the sun is off the pool at night until the sun starts to hit the pool in the morning (or as early as you can muster getting up!).  Such FC drop tests are done with the SWG turned off and you raising the FC level using chlorinating liquid (or 6% unscented bleach, if you cannot find liquid chlorine).  If you find an FC drop of more than 1 ppm, then you've likely got algae growth so the FC/CYA ratio is too low and you need to target a higher FC level (after shocking the pool first with a higher FC to kill off the algae quickly).  If the overnight FC drop is low and your CYA level isn't high (i.e. 60-80 ppm) and if you find the daytime FC drop is high (> 2 ppm) then you need to raise the CYA level (and your target FC level along with it).

Many SWG manufacturers (at least in the U.S.) recommend a 1-3 ppm FC with 60-80 ppm CYA, but this is not sufficient to prevent algae growth in some pools (ones rich with algae nutrients; phosphates and nitrates).  Having a target of at least 3.6 ppm FC with 80 ppm CYA (say 4 ppm FC to make things simple) will work.

If you want to maintain a lower FC then the roughly 5% of CYA target, then you would need to use supplemental chemicals at extra cost (i.e. weekly PolyQuat 60 algaecide, or a phosphate remover, etc.).  Another approach that just involves a mostly one-time dose is to add 50 ppm Borates to the pool.  This acts as an additional pH buffer, but also is a mild algaecide.  You can read more about [url=http://www.troublefreepool.com/pool-school/water_balance_saltwater_generator]Water Balance for SWGs[/url].

Richard

[Jonzjob]

Enjoy Giles, have a G&T for me and munch away at the Alphabeti Spagetti if you can translate it?

[Théière]

Actually Jonzjob, I thought that was one of Chemgeek's shorter more succinct postings and more to the point correct, although a few less abbreviations would help some readers.

Agree with the G&T though [;-)]

[Wilko]

Hello all

Could do with a little help here.

Background; I bought a Solarmatt to heat the salt water pool, and it works very well...........at heating the pool. I have no connection with this company. Unfortunately this brings a host of problems I have not previuously encountered. My salt content is too low even thought i have added 150kgs of salt over the past 2 weeks...........I assume that this is because the water temp has been upto 34 degrees. I have now 90% bypassed the solarmatt and the temps is 28 degrees. PH 7.3 and salt 4.3 with the pump running for 16 hours. This is all my magic box of tricks tells me. I have black mould growing a little by the water line and although  the look of the water is acceptable i know it could be clearer and more sparkling. Do I need to buy a bit of kit to give me more readings eg cynauric acid (whatever that is) and if I do what do people suggest ?? Also what do I need to do to stop having to buy copious quantities of salt...............short of buying a salt mine ?

I would be most grateful for any advice...............but please keep  to laymans terminology as technology not a strong point.

Happy swimming

Wilko

[Théière]

Hi Wilko,

Although not the most accurate an aquacheck dip strip will give you a reasonable guide to cyanuric acid level and yes add some if you are not already doing so but be careful if you over do it you will have to drain some of the water off and top up with fresh.

You do not say what your chlorine level is and from the fact that mould is growing it must be pretty low so whilst you are out shopping buy yourself some choc or 9.6% javel from a brico shed, you are going to need it.

What size is your pool?

[Poolguy]

[quote user="Wilko"]

Hello all

Could do with a little help here.

Background; I bought a Solarmatt to heat the salt water pool, and it works very well...........at heating the pool. I have no connection with this company. Unfortunately this brings a host of problems I have not previuously encountered. My salt content is too low even thought i have added 150kgs of salt over the past 2 weeks...........I assume that this is because the water temp has been upto 34 degrees. I have now 90% bypassed the solarmatt and the temps is 28 degrees. PH 7.3 and salt 4.3 with the pump running for 16 hours. This is all my magic box of tricks tells me. I have black mould growing a little by the water line and although  the look of the water is acceptable i know it could be clearer and more sparkling. Do I need to buy a bit of kit to give me more readings eg cynauric acid (whatever that is) and if I do what do people suggest ?? Also what do I need to do to stop having to buy copious quantities of salt...............short of buying a salt mine ?

I would be most grateful for any advice...............but please keep  to laymans terminology as technology not a strong point.

Happy swimming

Wilko

[/quote]

I presume that the black deposit is the water line fungus that feeds on the oils deposited there after swimming and not really to do with your water chemical balance. In which case a water line cleaner, biodegradable if possible would be appropriate - I suggest Aqua Clean as it will not impact on your water quality.

I presume that the measurement '4.3' for salt is in Parts Per Hundred giving you 4300ppm which should be a enough for most electrolysers to make chlorine. As you probably know 34°c is way too high for a swimming pool liner and will surely invalidate the warrantee.

Andrew

[Wilko]

Hi Teapot

Thanks for replying.

I bought some 9.6% Javel today so I guess i throw some n there...............bit of guidance of how much appreciated. I don't know what the chlorine level is cos the magic box of tricks doesn't indicate this measurement............that's why I asked what to buy that measures everything.

The pool is 15x4 metres, depth from 1.10m to 1.80.

Thanks for your comments so far i appreciate any guidance you can give me.

Regds Wilko

[Wilko]

Hi Poolguy

Thanks for your reply.

I went to my local pool shop and asked for Aqua Clean but didn't have any, will try elsewhere demain.

Yes swimming in 34 degree pool lots of fun but hardly refreshing, bit of an oversight there on my part as to the efficiency of the Solarmatt.........think I've got that under control now. I don't have any warranty problems as we designed and built the pool ourselves,  it's concrete covering more steel than you can shake a stick at...........so no problems with a liner....... but thanks for the thought and your reply.

Any further advice you deem relevant would be most gratefully received..

Rgds Wilko

Ps If of interest to you... see:

http://www.maspomona.com/en_swimming_pool_area.htm

 

[Jonzjob]

Hi Wilko, can I ask the question of why did you choose a salt pool?

Just querious.

It looks really good![:D]

[Théière]

[quote user="Wilko"]

Hi Teapot

Thanks for replying.

I bought some 9.6% Javel today so I guess i throw some n there...............bit of guidance of how much appreciated. I don't know what the chlorine level is cos the magic box of tricks doesn't indicate this measurement............that's why I asked what to buy that measures everything.

The pool is 15x4 metres, depth from 1.10m to 1.80.

Thanks for your comments so far i appreciate any guidance you can give me.

Regds Wilko

[/quote]

Morning Wilko,

I am guestimating your pool at around 75-80m3 so roughly 15 litres of javel should get you somewhere around 5ppm of chlorine higher would be better. Shocking a pool requires the chlorine level between 5 -10 ppm so if you have not already done so buy some poolcheck test strips as these test the clorine levels higher than DPD pastile test kits which are much harder to tell the difference between 3ppm or 5ppm.

It would be worth diluting the javel into a bucket or buckets of pool water and then distributing around the pool also making use of the return jets to help you mix.

 

 

[Wilko]

Hi Teapot

Thanks for all your help in this matter............the Javel worked a treat and got rid of the black algae and then I got everything balanced up PH etc and hey presto sparkling water. Just one last question....is there some sort of machine, not poolcheck strips, that I can buy that measures everything in one go ??

Thanks again

Regards Wilko

[Wilko]

Hi Jonzjob

In my youth, many moons ago, I was a serious swimmer so swam in lots of different pools, mostly chlorine, which at times could become a somewhat painful experience........i didn't like wearing goggles. When I was in my mid 20s I swam in a salt water pool and found it to be so superior to chlorinated pools in terms of water quality and I certainly didn't have to wear goggles. In the past couple of years I have also noticed that salt water seems to be less attractive to wasps, however my only comparison is a friend's chlorine pool which is wasp city on the occasions I've had a swim there.

Rgds Wilko  

 

[Jonzjob]

I am at a bit of a loss here Wilko because the only difference between a salt and a chlor pool is that the salt pool has salt in it? They both have to have the same amount of chlor to sanitise the water. The PH is controlled the same way with acid, hydrocloric or sulphuric, the stability is cyanuric and the TA is the same.

Our pool does not smell or taste of anything. I don't have to shower when I come out of it and I really don't understand why there is such a difference. Also if salt pools are so good then why are they not allowed with the public pools? Is it because they can't  stay up with demand of changing bather loads that can occur with public pools? I have no axe to grind either way, but our pool is the one we bought along with our house here and it is the one that I know, possibly a little better than some but that is because I tend to look at the way things work?

If you are in a pool and you can smell 'chlorine' then it doesn't matter what kind of pool it is it's because there is not enough chlorine in it and it is not chlorine that you can smell and that is making your eyes sore, it is chlorimine, the combination of chlor and amonia.

Bromine pools. Wow, lets get away from chlor! Not a chance because they too need chlor to activate the sanitisation. So unless you go to one of the 'fringe' sanitisers that I know nowt about, active oxygen I think is one of them, then you are into chlor and about 1.5ppm at that?

Someone who is much better than I at this game could tell me netter and I would welcome the knowledge if I'm wrong?

Good luck and enjoy your pool as much as I do ours![:D]

 

[Wilko]

I've been at a bit of a loss for years. I understand the basics, cos I have to...........but otherwise I find the whole subject a complete bore, I just don't do science........ but each to his own. My personal observations are in no way meant to be scientific. Just a preference for salt water as opposed to chlor, and in those days I lttle imagined I would be the proud owner of a pool, as I say I still prefer it but it is all just a non scientific comment.

If you invite me I'll pop in for a swim one of these days and we can compare your notes.

Happy swimming

Wilko

Ps I'm a computer illiterate as well cos I just can't make those smiley thingies work !! Should go after "notes"

[Théière]

Jonzjob you are quite right if a pool smells heavily of chlorine then there is something wrong as its the byproducts that are the danger and smell. When you test a healthy pool for free chlorine you should not get a reading higher than that for combined chlorine and if possible combined chlorine should be near 0

Why is that important because the byproducts are nasty and cause health problems and they are usually found at the surface and just above, right where your nose and mouth are when you are swimming.

I have no axe to grind on salt water generated chlorine pools either, the system works. For pretty much the same money you can buy a direct dosing system as you know which seems to be far easier to controll although you do have to handle bleach and acid. The problem comes with some salt water generators being of low quality and unable to supply enough chlorine. 

The reason they are not used commercially is as you said, if there is a party of people and some pee in the pool or worse a direct shot of chlorine can be administered, not a trickle of chlorine over several hours.

I use a fringe sanitiser in my pool at the moment, it's a study thing, there is so much bull spoken about I thought I would test it and the results are very good. I will get a sample of water tested by the bacteriologists again this year to see how its is going.

The activ oxygen brigade, most of the electrical generated versions are psuedo science and do not actually do what they say although with the latest technology this may change in time. Chrish is looking at the oxineo an expensive bit of kit but the first of a new breed. They claim no chemicals, not exactly true as you add a small level of salt which is likely to be turned into chlorine but it has other benefits so we watch and wait.

I researched the popular U.V. sanitisers, they are great for fishponds but when you add chlorine to your pool they can produce even more nasty byproducts.

Wilko, there are testers which receive good reports like the scuba+ photometer that Chrish and poolguy retail, I have a leaflet in front of me about the exact micro which apparently can acuractly read the poolcheck strips to a much higher degree than we humans can and the lovibond photometer.