Dead water

[JSA Aude]

Wondering if anyone has any experience or knowledge of the above problem.  We have just opened the pool up after winter, taken a sample of water to a pool company and they are saying it is dead, need to empty and re-fill the pool twice in order to get up and running.  It is a chlorinated pool 10 x 5 so alot of water to be wasted if this is the case.  Thanks.

[chem geek]

Dead pool water?

Did they give you water chemistry test results or any explanation by what they meant by "dead"?  I can think of a few possibilities and solutions for them.

One is that the pool was "let go" over the winter (i.e. not chlorinated).  Sometimes, soil bacteria get into the pool and consume the Cyanuric Acid (CYA) in the pool producing ammonia (technical info on this is [url=http://www.troublefreepool.com/degradation-of-cyanuric-acid-cya-t8880.html]here[/url]).  If this happens, then the pool appears to have an insatiable chlorine demand -- you keep adding chlorine, but get no Free Chlorine (FC) measurement.  For every 10 ppm CYA that bacteria consume, they produce 3 ppm ammonia and that takes about 24 ppm FC to get rid of.  Some of the ammonia can escape via other means (outgassing; consumption by algae) so to know if you've got ammonia in the pool you can buy an inexpensive ammonia test kit from a pet/fish/aquarium store.  It takes at least 8x the ammonia level as cumulatively added FC to get rid of it.

Another possibility is that the Cyanuric Acid (CYA) level is very high, above 80 or 100 ppm, usually from continued use of stabilized chlorine (Trichlor tabs/pucks, Dichlor powder/granular) products.  This can also appear to be an unusual chlorine demand if there is a nascent algae bloom.  Unfortunately, for high CYA levels, the only way to lower them is via water dilution, so a partial drain/refill.  The long-term solution is to use a fixed amount of CYA and then use unstabilized chlorine (i.e. chlorinating liquid or bleach) which you can have automatically dosed using an automated dosing system such as [url=http://www.poolguy.fr/products/product-sanitization.htm]this one[/url] from the Pool Guy.

Another possibility is that the Total Dissolved Solids (TDS) measurement is high, but this isn't a real problem since usually the TDS is just salt (sodium chloride) that has accumulated from chlorine usage.

Richard

[Jonzjob]

S, have you checked the levels of free chlor, PH, and cyanuric acid along with the total alkalinity of the water in the pool? What does it look like, is it milky, green or what? Do you have algea on the pool surfaces? Never mind what the pool shop have told you.

What kind of winterising did you do? Did you drain the pool down or did you keep the level up and run the pump hrough the winter?

Give us a clue?

[JSA Aude]

Hi J, we didn't use the pump during the winter but partially emptied it.  Green water and sides but no yuk floating. S.

[Jonzjob]

I may well be shot out of the water S, but I would fill the pool and shock it after checking the total alkalinity, PH and the cyanuric acid levels.

The TA should be around the 180ppm mark, the cyanuric about 50ppm and the PH close to 7.2.

I take it that this is not a salt pool?

[JSA Aude]

Thanks, J is going to give it a shot - no, not a salt pool. S.

[Théière]

Go for it JSA,

Your water seems to be much more "alive" than "dead" alive with algae [:D]

Whilst changing your pool water maybe one idea, changing your pool shop should be higher on the list as its easier and cheaper.

What you have described it not a major problem, remember to filter and backwash, continously for a couple of days and as chemgeek has said dump plenty of bleach into the pool to choc it.

Backwashing is very important at this stage its ok to backwash every 4 hours initially and rinse too.

You'll soon get it back up

[Jonzjob]

I have found that most if not some of the pool shops here have less idea about water chemistry than I do! I asked one big one if they had any sulphuric acid to bring the PH down. Their answer was no but they had PH minus, at about 3 times the price. I had a look at the label and pointed to where it said that it was 100% sulphuric acid. The bloke just gave me a blank look!

Not a clue!

I now get my H2SO4 from the bricos in 1 litre bottles. It is a heck of a lot cheaper and a lot easier to handle.

Just as a matter of interest. I use one of the manual syphon pumps that the French use for their parafin when they fill their heaters to transfere the javel into the 20 liter container for the auto feed for the pool.

Remember when you are refilling your auto feed containers ALWAYS put the chemical into the water and not the water into the chemical!

[JSA Aude]

Pea Green Pool boy here,

The problem arose last year when we switched from water pumped directly from the River Aude to water piped from the Black Mountains, seriously alkaline.  Following the advice of the lovely and ever helpful Natalie at Everblue Carca, have twice changed 50% of the water which originally had a PYA of 120 ppm now down to 40 pp.  After triple backwash I am to introduce algicide and aerator compound and after a week a non-chlor choc.  Expensive but worth it if it shuts the wife up.  Will report results!  Cheers and thanks for your input.

[Jonzjob]

I had an idea for a song J.

"Won't you make my green pool blue"?

Why non chlor shock and what does it have in it? Is it a chlor pool?

[Jonzjob]

PYA??????? [8-)]

[Théière]

Yes, PYA?? [8-)]

Maybe CYA cyanuric acid?

JSA, is Everblue where you have been told your water is dead?

Hold back on the expensive chemical and use cheap bleach to do the bulk of the work, you can change over later once it's clean.

If your water is seriously alkaline you MUST get the PH down to 7.2-7.4 first, Run the pump on filter continuously and backwash every 4 hours

That will kill the algae quickly and as you will be backwashing more frequently save you wasting good money on algicide.

Have you got some pool testing strips or chemical?

 

[Jonzjob]

It would help the chlor to kill the green if you give it a good brushing while you are shocking it too. That will get the algea that is stuck to the surfaces into the circulation and the chlor can sort it out!

Kill the green!!![6][6]

I agree with Teapot, use javel, it will be a lot less expensive than what blue thingie will sell you. I was not impressed with the blonde in there?

[Théière]

Oh she's a blonde, not a green as well [:D]

Are you colourist![:P]

[Jonzjob]

No Teapot, a cheepist [:P][:P][:P]

And a perfektionest [8-)]

As Andrew will know, nothing will suck-seed like a budgie without a beak?

[Northender]

Hi Teapot

Interested in your comments about backwashing frequently , something which I have to do when I open our pool after a long winter closure.

I have never understood what the "Rinse" option is for on the multi-way valve.

Perhaps you could enlighten me?

 

[Théière]

It's when you add the fabric softner [:D]

It helps rinse the sand properly, sometimes when you backwash and then filter you will see some dirt get blasted back into the pool via the returns.

Rinsing just clears that before starting to filter again, when trying to clear the pool after winter its worth backwashing and rinsing frequently as the sand soon becomes clogged.

Of course there are alternatives to sand which do a much better job.

[Jonzjob]

Hey Teapot! Wots sand, it's the stuff you make cementacrete with init?

As you say Zeolite does a much better job!

[Northender]

Thanks for that teapot

So rinse  is passing water through the filter in its normal direction but "wasting" rather than directing it back into the pool?

Our filter is a Diamantes (I think thats how you spell it) seems to work OK. 

Its just that first few days when I open the pool thats hard graft.

We don't open the pool until late May ,which is probably too late , and the "green stuff" as gotten hold.

[Cat]

I was told by the guy that supplied our pool that every time I backwash I should do so for 3 minutes, and should rinse for 10 seconds afterwards.

We use Zeolite too, great stuff!  I sneaked a peak at the pool a few days ago ... crystal-clear (but we did leave the pump running 20 minutes every night through the winter).

[Jonzjob]

Same here Cat, but it also runs 5 mins every hour if the temp drops to 5 deg.

On your multi port valve there will be a small clear cup looking thing on the side where the backwash water comes out. You should backwash until that goes from cloudy water to clear. It's easy to see especially if you hold a torch behind it. Then switch the pump off and change the valve to rinse and do the same till it's clear, probably about 10 to 15 secs. That way if the filter is not very mucky you will probably need less than 3 mins, but you will see it anyway.

The reason that you should always turn the pump off before changing the position of the valve is that you could lift the seal inside with the water flow and pressure. Our seal was damaged before we got the house and a new one cost me 25€ almost 4 years ago.

[Théière]

Zeolite is very good, also Dryden Aqua's AFM which I am using this year.

[Jonzjob]

AFM is an Activated Filter Media, manufactured and activated by Dryden Aqua under ISO procedures  to have  a high negative zeta potential and catalytic self sterilizing properties.

Well that makes it crystal clear, not just the water?[8-)]

I will read more about that T.