My pool has turned green!

[Campo Kenny]

Beachy, serious mode on.

I know where you're coming from re. the agua fuerte debate, and your main point seems to be that it is daft to bathe in such a toxic nasty chemical.......agreed beyond doubt.
I must state I have never used AF in my pool but I'm ridiculed by some over there for buying the proper stuff.

Anyway to get to the point, when we arrived at the place a few weeks back my PH's were a touch high so I put the dosage of my PH minus in the bucket and procceeded to fill the bucket with water from the outside tap in bbq area.
Due to the convexed and concaved design of the bottom of my pale I suffered severe blowback and got drenched with the undiluted mix.

I had my shirt off and thought nowt about, I prepped and fettled the pool and then started itching on my arms, it then turned into incredible burning all over my top half.
Being a wimp I staggered in and Mrs. threw me in the bath.

Seriously, this stuff was aggressive and don't believe now it is any milder than AF.
Love to hear peoples comments on this as it opened my eyes.

Kenny

[El Cid]

Seriously, this stuff was aggressive and don't believe now it is any milder than AF.
Love to hear peoples comments on this as it opened my eyes. Kenny

It's a good thing you had your eyes closed or it would have been worse!

They are both nasty chemicals and just as dangerous as each other. The only reason that Dry Acid is preferred to AF (for domestic as opposed to commercial pools) is that it is easier to handle safely - in theory - not always in practice as you found out.

The MSDS (Material safety data sheets) for each are as follows:-

For Pool Acid (Sodium Bisulphate):-

Harmful if swallowed, inhaled or in contact with skin. Corrosive - causes burns. Very destructive of mucous membranes.

For Agua Fuerte :-

Corrosive. Inhalation of vapour is harmful. Ingestion may be fatal. Liquid can cause severe damage to skin and eyes.

Personally I find that pouring AF from a bottle straight into the pool at water level is safer than mixing powder in a bucket. Either way care is needed.

Once diluted in water they are quite harmless and both act the same way from a chemical point of view.

Sid

[Beachcomber]

I always put the granules in a bucket then lower it gently into the pool and allow it to half fill with water.

I allow the diluted portion to enter the pool then half fill the bucket again until it has all been dissolved. I do all this at water level so as to avoid splash back etc.

Incidentally, you can also do this with calcium hypochlorite if you find you need to use it. I don't like putting chemicals straight down the skimmer but normal chlorine granules do not dissolve quickly whereas calcium hypochlorite does.

[Babby]

Sodium Bisulphate is used in household cleaners and in short it is nothing more than a mixture of salt and agua fuerte.

En fin - agua fuerte CAN be used to lower the ph in your pools.

[Beachcomber]

I have never claimed that aguafuerte will not lower the pH in a pool.

Aguafuerte, by definition, is a liquid whereas sodium bisulphate is dry. I'm not sure what the result of adding salt to aguafuerte would be but I doubt it would turn it into a dry acid.

[El Cid]

Sodium Bisulphate is used in household cleaners and in short it is nothing more than a mixture of salt and agua fuerte.

En fin - agua fuerte CAN be used to lower the ph in your pools.

Chemically that is incorrect.

You either mix Sulphuric acid with caustic soda or salt.

You certainly dont use Agua Fuerte.

For the budding chemists out there:-

Sodium bisulfate is produced by two methods. One method involves mixing stoichiometric quantities of sodium hydroxide and sulfuric acid which react to form sodium bisulfate and water.

NaOH + H2SO4 → NaHSO4 + H2O

A second production method involves reacting sodium chloride (salt) and sulfuric acid at elevated temperatures to produce sodium bisulfate and hydrogen chloride gas.

NaCl + H2SO4 → NaHSO4 + HCl


Either way, you are quite right - AF can be used to reduce pH.

You could also use Sulphuric Acid but mixing that with water can be really dangerous although the end result would be the same.

Sid

[country boy]

Incidentally...has anybody noticed that Agua Fuerte bottles have the Haz-Chem symbol in Espana as " Irritant"...would hate to come across any "corrosive" products on that scale

[Beachcomber]

...AF can be used to reduce pH...

In the same way that you can buy what passes for food at Lidl but I wouldn't touch that either!

[Campo Kenny]

Good info Sid.

Beachy....I'll get yer coat

[Beachcomber]

On a more serious note and to go back to the title of the thread, a friend called me yesterday to say he had a problem with his pool. It had gone green and murky despite having a pH of 7,5 and a free chlorine reading of 2,0ppm.

However the cyanuric acid level was way off the scale (well over 100 mg/l) and this was what was causing the problem. The free chlorine had been locked in by the cyanuric acid and was not sanitising the water properly.

The only way to cure high levels of cyanuric acid is to run off some water and refill but the chemical is then added again when you dose with more chlorine so it is a vicious circle.

The answer is to use unstabilised chlorine, preferably in the granular form of calcium hypochlorite rather than the liquid, sodium hypochlorite. This does not contain stabiliser so when you backwash and add new water it dilutes the cyanuric acid over a period of time.

Once you get down to a cyanuric acid level of between 30 and 80 mg/l you can revert to normal chlorine in granular or tablet form for a while.

[El Cid]

The answer is to use unstabilised chlorine, preferably in the granular form of calcium hypochlorite rather than the liquid, sodium hypochlorite. This does not contain stabiliser so when you backwash and add new water it dilutes the cyanuric acid over a period of time. .

Is that the same as the the stuff that is sold here as "Choque" chlorine in powder form ?

Presumably the reason for preferring the powder is because it is safer to use.

When I had a pool in the UK I used the liquid version in the spring to clear the very green pool after the winter rains etc. It usually cleared the pool within 24 hours. If I remember correctly it took a pretty big dose - like 5 gallons at a time. It certainly got rid of the frogs!

Sid

[Beachcomber]

Yes, probably the same thing because it means that you can shock dose with chlorine without increasing the cyanuric acid content.

When I buy it I ask for calcium hypochlorite which is the name it is sold under by CTX. It costs about the same as normal granular chlorine but it only has about 65% active content as opposed to 90% in stabilised granular chlorine.

I think the problem with the liquid chlorine is that it has a fairly short shelf life and if you get an old batch it doesn't do much good. You can store the calcium hypochlorite for longer and mix it up as required.

[country boy]

Can I ask a daft question? What happens to the chlorine in the water when the sun shines on it, which I know is what a stabilizer stops to a large extent?

[El Cid]

Can I ask a daft question? What happens to the chlorine in the water when the sun shines on it, which I know is what a stabilizer stops to a large extent?

When you add chlorine to water it forms Hypochlorous Acid HOCl.

Sunlight breaks this down to Oxygen and - wait for it - Hydrochloric Acid.

So it seems you are swimming in Agua Fuerte whether you like it or not!

Sid

[Babby]

On a separate note if some of you knew what went into toothpaste you probably wouldn´t use it, eh

Agua Fuerte is hazardous there is no doubt, but not when diluted to the correct proportions - nobody would want to swim in neat agua fuerte or any other chemical that goes into the running of a pool, but diluted it is deemed OK to swim in.

As for LIDL - it doesn´t come into the equation but since it has been mentioned I would like to point out that a number of major buyers for large chains of supermarkets buy their products in the same place and bid for the items - it is only a snobbery / class thing to buy your goods in one place or another and sometimes the only difference is the packaging and brand name - the average person can determine from one store to another whether an item is good quality or not.

[Faire d'Income]

As for LIDL - it doesn´t come into the equation but since it has been mentioned I would like to point out that a number of major buyers for large chains of supermarkets buy their products in the same place and bid for the items - it is only a snobbery / class thing to buy your goods in one place or another and sometimes the only difference is the packaging and brand name - the average person can determine from one store to another whether an item is good quality or not.

Seriously digressing here but certainly in the UK, that's incorrect. I've been on numerous courses with both suppliers and buyers from within the UK retail sector and there are significant differences in the quality and specification of the major supermarkets, particularly for fresh produce.

The Co-Op and Waitrose tend to have the higher specifications with the other chains lowering the bar, usually in line with what their customers will put up with. That's why, generally speaking you'll find that local butchers are more expensive but then you get what you pay for.

[peteroldracer]

Note that Carrefour and Dia are owned by the same group, and I don't think they buy the same quality goods for both sorts of outlet!

[peteroldracer]

Another question on pools: ours has the usual edging stones - started out white, but have got stained by the red earth round here. Anyone know a safe stuff to clean them?

[El Cid]

Have you tried a pressure washer?

Sid

[country boy]

Have you tried....dare I say it....Agua Fuerte?