Algae seems to be beneath the grout?

[LizaC]

Hello

I hope somebody can help! I live in Spain and our swimming pool is 4 x 8 m and it is in a south facing garden. It has a tiled surface and we have a pump and filter (sorry I don't know the type) The filter is filled with glass particles not sand.

Anyway, the problem we have is with green algae on the walls of the pool and it seems to be beneath the grout. I'm am in a constant circle of cleaning and adding chemicals and I'm fighting a losing battle. I normally keep the pH at neutral, add algicide once a week, add chlorine granules every night and we have slow release chlorine tablets in a thing that floats around in the pool (I am using a lot of chlorine and struggle to keep the level up). I brush the walls and floor of the pool and clean it with a hoover. When I brush the walls of the pool the grout flies off like powder and there are some areas where it has fallen off. When I look down at the walls, from the top, I can see areas where it looks like the algae is literally pushing the grout off the wall, I go and remove it with my hand and turn it over and the algae is on the underside of the grout (basically in the walls). So I think all the chemicals and cleaning is just touching the surface and I am never getting rid of the algae that is growing inside the walls.

As I said at the start I am in a constant cycle of cleaning, everytime I brush the walls the pool becomes cloudy, I wait a couple of days (put some flocculant in it) the water clears, I hoover it, brush the walls again to stop them being slimy, the water becomes cloudy and off we go again. When I was reading some posts on this forum, I read something about getting your pool cleaned once a week.....I am literally at mine everyday and if I miss a day the walls are green. So my husband and I have decided today that we definitely need to empty and regrout the pool, but I am worried that we are just going to skim over the problem. Because the algae seems to be "in" the walls is there anything I can do to get rid of it? Will regrouting "kill" it? Any advice would be appreciated. Thanks in advance.

Liza

[Teapot1]

Hi Liza,
So you add algaecide weekly, as you may habe deduced algaecide doesnt really work does it, its a pool industry con. You put algaecide in and them some of your chlorine gets used up burning it out so you add more and then more chlorine in a cycle that keeps pool suppliers really happy. Then in despair you ask for pool shop advice and they sell you more stuff, that mainly doesnt work either. When they run out of ideas, they tell you to empty the pool and add fresh water.
Anyway back to your issues. Stop adding algaecide. What granules of chlorine do you add? Two main types sodium hypochlorite or calcium hypochlorite. Also do you have an accurate water test results and not from dip strips which are pretty hopeless. Very important is the cyanuric acid level (CYA) as this product is needed to protect the chlorine from being burned up by the sun but too much reduces what is available to kill your algae. Yes algae can grow into the grout but likewise we can still kill it by super chlorination. Please com back with water tests and we can move on to sorting out your pool.

[LizaC]

Hello

Thank you for getting back to me. The granulated chlorine is 100% sodium dichloroisocyanurate dihydrate (that's translated from Spanish on the the back of the tub). The tablets I use are 10 effect tablets and their ingredients are trichloroisocyanuric acid, aluminium sulphate, copper sulfate, boric acid etc. I add the granules daily in the evening and 1 - 2 tablets a week in the floater. My water testing will be no better than the test strips! I collect a sample of water and add yellowish drops to test the chlorine and then reddish drops to test the PH. I can easily keep the pH in the 7.2 - 7.6 range but was struggling to get the chlorine level up, it was always on the low side. But what you say about the algicide in your post above makes sense, I think a combo of algae, ineffective algicide and sun are just eating up the chlorine.

Anyway, there was more grout flaked off and on the floor of my pool that what was on the walls. It had been several years since it had been grouted and refilled so I have emptied it and spent yesterday pressure washing and cleaning it. I am going to regrout this week and start fresh. Going forward I want to avoid this happening and I need to educate myself better on pool maintenance!

Could you please advise on a good water tester? I have looked online and some of them only give chlorine and pH readings, nothing about specific CYA levels.

I hadn't heard of CYA but when I googled it it said it was a stabiliser which I had heard of.....I don't use a separate one, it is in the 10 effect chlorine tablets.....should I be using separate CYA granules?

Could you please advise on what I should put in when I "set up" my pool again and what to do going forward to maintain it. There are so many conflicting articles online and I'm not sure what to follow.

Finally, I think I mentioned that my pool is in a south facing garden and it literally gets the sun on it all day. Will this effect the processing of the chemicals? I imagine on the pool chemicals what it says "on the back of the packet" is a guide, do I have to take into account the sunlight too and adjust accordingly?

Sorry for all the questions, every summer is a guessing game and I want to move forward in the correct way!

Regards

Liza

[Teapot1]

Hi Liza,
Ok, your granules are, to shorten the name, Dichlor, this means 2 molecules of chlorine and the rest cyanuric acid (CYA).
Your tablets are, to shorten the name Trichlor, this means 3 molecules of chlorine and 1/3 less CYA. From this you can probably deduce that the granules will raise your CYA 33% quicker than the tablets you use whilst giving you 33% less chlorine for your money. You may wish to lessen the use of the granules for the future. That said, when you refil the pool you will start with 0 CYA so the sun will burn up your chlorine in around 2-3 hours meaning you'll need to add more, best done at sunset so it can work overnight without the sun.
CYA controls your pool water so to speak, it's really important. Why is a tester not commonly found in pool shops? Because they can make lots of sales from not telling people the simple cure for most problems in pools. Dip strips may guess at pH, chlorine but are useless for CYA, sure they will change colour so you think you are getting a reading but it will be wrong.
If you are doing a regrout make sure you use a swimming pool full and constant immersion grout like Ardex. You could use an epoxy grout like Kerapoxy from Mapei which I know is stocked in Spain if you cant get Ardex. Its a little bit trickier to use so work quick and clean as once its stuck, its stuck!

Yes full sun does burn up the chlorine hence why a CYA level of 50-70 ppm may be a good point to reach, with your use of dichlor and trichlor I would hazzard a guess that your CYA would be near 200ppm rendering your normal level of chlorine insufficient to keep algae at bay, its a common scenario.

There are good test kits available, someone managed to get a Taylor test kit in Spain, If you cant find it I will ask my friend where he got his.

[LizaC]

Hello

Thanks for the info. I have ordered the Ardex grout so I'm just waiting for that to arrive. When I have grouted, how long do you recommend leaving it to dry before I can start refilling the pool?

I have had a look online for the Taylor text kits....one on Amazon was 200 euros! It is hard to find a kit that tests for CYA! Lots of test strips or digital ones but the ones where you drop the solutions into your sample of pool water are hard to find. I have found the same kit here for half the price.....is this the one you recommend: https://hidromaronline.com/producto/tes ... e9f9528509

So probably a stupid question..... if the CYA in the pool doesn't evaporate and the level remains more or less constant unless there is a lot of rain or you empty and refill.....if I need to add more chlorine, the tablets and the granules I use both have stabiliser in them so how do I add more chlorine and not raise the CYA?....can you get just pure chlorine without any stabiliser in it? the place where I buy my pool chemicals is called Leroy Merlin (it is like B & Q - if you are in the UK) and everything in there is non specialised and for home use eg the 10 effect tablets with everything in them, so I haven't found just 100% chlorine....to be honest, I thought the granules were just pure chlorine lol!

Thanks again

Liza

[Teapot1]

Hi Liza, the Taylor K1005 would be good. The 2006 is probably the best but if you dont want to get nerdy and would rather enjoy the pool the K1005 will be fine.

No its not a stupid question and in fact will elevate your pool maintenance from now on. Yes very familiar with Leroy Merlin as I worked predominantly in France with some time in Spain. Look for the 20ltr containers of Eau de Javel 9.6% chlorine and its unstabilised hurray! Cost varies but arount €18 for 20 litres.

How deep is your pool?

[LizaC]

Hello

It is 4.5 x 8 m and it's 1.3m deep at the shallow end and 1.6m deep at the deep end.

Thank you regarding the test kit advice and info about the chlorine!

Regards

Liza

[angshu]

First time with this issue. we have been trying to get our pool clear for over 2 weeks chemicals get balanced but we can’t get rid of the green and not being able to see the bottom. Most recently did a super shock at 10 until pool was a milky blue then added pool first aid. after 48 hours we could see the bottom and thought we were in the clear. We put our Dolphin robot cleaner in(first year having one) and after an hour our pool was cloudy green again. What is going on?

[Teapot1]

Dirt and debris falls to the floor, left undisturbed it looks like the water is clear as gin until it gets stired up by people or a pool robot. So now you know that pool robots are not as good as a human going carefully with a manual cleaning head. Chems balanced means nothing when you have a problem you have a problem. Now to go and see what pool first aid really is, so many miracle cures in pool shops that you generally do not need.