My pool has turned green!

[poshtotti]

The pool was lovely on Saturday, chlorine levels fine, water was crystal clear!
After a couple of days of strong winds it's suddenly turned green!!!! WHY?!!?
Everything is at the right levels, the pump is running 4-8 hours a day. It's horrible, even over the winter it didnt look like this. It's not like algae sticking to the walls, it's just the water has turned a nasty colour.

Anyone know anything I can treat it with? - I think I need some shock treatment. I usually use the floucculant bags/tablets to clump the dust together, but think I need something more than this.

Friends arriving today & it's a little embarrassing

[detourer]

I was having a nightmare time with our pool, even thought of turning it into a huge flower bed!

Without looking it up someone on this site gave some great info [only a week ago I think]....and also gave a link to a pool web site......

One of the first comments I read was that 90% of pool problems are NOT chemical related OR on need of a chemical solution. It's mechanical i.e. what you are doing with your pump/filters/valves etc.

I now have a sparkling, clear pool.......................Thanks whoever that was

[Faire d'Income]

You'll have to shock it with chlorine.

[Beachcomber]

Try the flocculant tablets anyway. Also make sure the pH is as close to 7,4 as possible. The chlorine should be between 2 and 2,5 ppm

If you need to shock dose do so with chlorine granules.

Are you using a test kit that has small tablets as reagents? The liquid reagents are not reliable. The OTO liquid has been banned in many European countries and it also measures total or combined chlorine rather than free chlorine which is the reading you need.

The pool always looks better in the winter because the water is colder and the pool is not used so much. Once the water temperature hits 28ºC you need to be extra vigilant with the chemical levels and pump running time.

I know there are people on this forum who disagree with me but depending on the size of the pump and filter in relation to the cubic capacity of the pool the filter should be operating for at least eight hours during the daytime. Always make sure the filter is running when someone is using the pool and for at least an hour afterwards.

[ValL]

Green nearly always means algae - we had strong sunlight recently for first time this year - unless someone has actually added a dye but highly unlikely. Dont shock with chlorine but shock with special pool algicide then prepare to use flocculant a few days later when all the algae has died off and the water is wanted to fall really clear.

[Beachcomber]

I think this is the thread Detourer is referring to. I contains the link to the pool site:

http://www.andalucia.com/forums/viewtopic.php?t=11293

I have to say that I never use algicide. If you do decide to do not use too much otherwise you will end up with a very frothy pool.

[ValL]

the post above under my name was from my husband, an environmental scientist specialising in water

[peteroldracer]

If in doubt take a sample to your usual pool chemicals supplier - and if you buy in the supermarket, take it to a proper shop! They will usually advise you.
Agree with beachcomber btw on running pump at least eight hours etc. Apart from anything else it helps maximise pool temperature by stirring the colder water from the bottom up to the sun at the top, particularly if it is only getting infrequent usage i.e. not when three screaming grandkids are there on hols!

[laclotte]

Get Mr Poshtotti to look at the sand in the filter - I reckon it is like a block of concrete and guess that is your problem....just not filtering.
I have a great and easy way to solve it - let me know if necessary and will pass on details!

[peteroldracer]

I had this happen to me last year: shock the pool first, then add algicide (take supplier's advice from sample), then when the algicide has killed the stuff, add floculant to bind the dead particles and make them big enough for the sand to capture them. If the sand has set like concrete, your pressure will be all wrong on the gauge on top of the filter and you cannot have been backwashing properly! Leave the filtration running at least 24 hours, but keep your eye on the pressure - it can take several backwashes to keep the filter working, and a fair amount of topping up. Chances are your neighbours will have had the same algae drop in their pools, so you can become the local know-all and pool guru!

[laclotte]

Needs an awful lot more than just a backwash and filtering
Should this be the problem the solution is really simple however I am not prepared to put it on 'public view' just in case someone would not quite understand the different steps and I could be held responsible.
I will forward you detsils as to how I 'solved' the 'sand turning into concrete' ...you never really solve it .... you only correct it at the time. The proper solution is changing the sand in the filter..dreadful job!
Pools normally should be filtered corresponding to the number of daylight hours...........'Faire' would no doubt confirm this having learned this 'rule' in SA?.........the most pools per (white) percentage wise in the world.

[peteroldracer]

"What Color Is Your Swimming Pool?" (sic) by Alan E. Sanderfoot ISBN-10:1-58017-309-8 covers pools, spas etc from choosing which type to keeping it right. Has worked for me! Easily available here for around 25€

[Beachcomber]

Hard sand is usually caused by constantly high pH and liquid flocculant being allowed to get into the sand filter.

You can tell if this is the problem because the dust you Hoover up from the bottom of the pool comes straight back in through the return inlets as the water makes rivulets in the sand instead of being filtered by it.

Another indication is that the in water in the inspection bowl does not turn murky during the first few seconds of backwashing. Hard sand is usually dissolved by pouring hydrochloric acid over it but stand well back because this produces really bad fumes that can knock you out

The sand usually needs to be changed after about seven years because it literally wears out and loses its courseness, a bit like pebbles on the beach that are made smooth by the sea constantly passing over them.

[peteroldracer]

That last sentence was almost poetic, beachcomber - and perhaps suggests a suitable treatment for some of our less-sophisticated compatriots!

[laclotte]

[quote="Beachcomber" Hard sand is usually dissolved by pouring hydrochloric acid over it but stand well back because this produces really bad fumes that can knock you out
quote]

Thanks Beach!!! you said it not me! I would advise people to be really careful of the fumes......... and rather do it slowly.....do not pour a liter in the first time....rather 'drop by drop'. I also found that I had to open the sand filter each time and scoup off all the 5 year old junk..not a nice job...but works really well after 2/3 times.
Good luck!

[Beachcomber]

Yes, it's a disgusting job. You should use some kind of mask and even then stand clear each time you put a drop in. I cannot echo Laclotte's words of caution too strongly.

Poetic! I've been called many things but this is a first. Thanks Peter.

By the way, I didn't mean to disparage ValL's advice. My aversion towards the use of algicide is just a personal preference. It's not based on any scientific premise. It's just that I have never found the need to use it.

[pentaqua-new]

My neighbors reckon the olive pollen is greater than normal this year. Certainly my 'crystal clear' cubierta is a lovely yellow-green shade! I bought it for winter swimming, but it's being very useful keeping the pool clear and warm - though at 32C+ at times it's too damn hot.

[poshtotti]

WOW, thanks everyone, I didnt expect so many responses!

Hard sand is usually caused by constantly high pH and liquid flocculant being allowed to get into the sand filter.
You can tell if this is the problem because the dust you Hoover up from the bottom of the pool comes straight back in through the return inlets as the water makes rivulets in the sand instead of being filtered by it.
Another indication is that the in water in the inspection bowl does not turn murky during the first few seconds of backwashing.
The sand usually needs to be changed after about seven years because it literally wears out and loses its courseness, a bit like pebbles on the beach that are made smooth by the sea constantly passing over them.

Beach - Can you see my pool?!?! - You have certainly hit the nail on the head!! - I told our landlord about 3 months ago that I thought there was an issue with the sand as I have to clean the pool on "waste!" or the dirt comes back out the return inlets. I was told that it was 100% impossible it was the sand because it was new 2 years ago!!!

Mr poshtotti is away for 4 weeks so I think I'll leave the nasty smelly proceedure to him!!! Thanks though.

I have shocked the pool with Chloro granules, left the pump on all night & it is not green today, just a little dusty, so i've given it 2 backwashes & rinses & will leave the pump on a little while longer. I'll put the floculant bags in tomorrow & see what happens...............

THANKS EVERYONE
x

[Beachcomber]

You can check the sand by taking the top off of the sand filter nad trying to run the sand through your fingers.

It way well have been changed two years ago but it can go hard very quickly under the circumstances I gave.

Hope you get it sorted out.

[Beachcomber]

Just one other thought.

A couple of years ago I helped someone with a pool that wasn't circulating properly and discovered that the innards of the multiport valve had been taken out and put back in the wrong position.

Just make sure that the position marked 'filter' or 'filtración' is facing directly towards the filter. Also, if the seal inside the valve is worn, broken or unseated (caused by turning the handle without switching off the pump) the water can take the least line of resistance and flow directly back into the pool without passing through the sand filter.