Green algae appearing in corners of my pool

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D

Docker_rob

0
Feb 7, 2015
43
Perth - Australia
I am hoping someone can shed some advice on a problem I am having with algae starting to show in small corners of my pool

I am in Australia so in the middle of our summer. Over the last week or two, my SWC vinyl lined pool has started getting green algae (I think it is algae) in the corners and also around some fittings such as the plastic outlets on the pool wall. I can disperse it by brushing but a few days later it's there again.

I have had my water tested, chlorine levels are if anything high, Free and total chlorine are up around 7 ppm
Stabiliser level is good, alkalinity is good, salt level is good, ph was slightly high at around 7.5 but otherwise all other readings are within the expected ranges.

The water itself looks perfectly clear, but this algae starting has me worried, last year around the same time I had an algae outbreak of sorts, when the pool walls had visible algae on them. I brushed it off and shocked the pool and all went back to normal, but as chlorine levels are already high I am at a loss as to why I have algae growth again.

Appreciate any ideas or feedback.
 
The answer is really simple. You do not have enough chlorine in the pool.

I understand you think that is not the case but algae doesn't grow in the presence of ADEQUATE chlorine.

The problem might be in your CYA level or perhaps in your testing method.

Can you report your CYA in ppm? "Good" just doesn't help us.
 
Can you post the levels of everything please?

Where do you get your water tested?

What do you use for your chlorine?

Shock is really not a one time thing. Around here we call it SLAM. Here is the link to how we do it.
http://www.troublefreepool.com/content/125-slam-shock-level-and-maintain-shockingl

I am going to guess that it IS algae AND that your CYA (stabilizer) is too high for your chlorine level.

We can and will help you clear your pool up and keep it clear! Look below in my siggy to see the link to the test kits we use and love. You will really need to get the TF-100 XL as you will need to SLAM your pool.

Yes you will need to spend a little money BUT once you get your pool clear and balanced you will save LOTS of money and time.

A "free" pool store test is not really free if it requires you to spend money on products to "fix" your pool until the next time...

Keep with us and we can help you

Kim
 
I agree it should be the case but reading the results from my last water test (I had this done at the pool shop and had 2 tests over a week just to be sure) I did have to add some salt and acid after the first test but otherwise nothing else.

CYA or stabiliser level at last test was 61 ppm
Salt levels are 6200 ppm
Alkalinity 125
PH 7.5
Calcium 225
Iron 0.3
Copper 0.0

Free chlorine first test was 6.4 and second test 10
Total chlorine first test was 6.5 and second test 11.1

It certainly doesn't smell or seem chlorine is that high, I also ran a test with my home chlorine test kit and it also indicates high (above 6ppm) I can't tell over that with my home test kit.
 
Welcome to TFP Rob!

X 2 on what Dave said. I repeat this often because this is the simple truth about Algae. There is no mystery about this.
It cannot live when there is enough Free Chlorine in the water. Your stabilizer level is the likely culprit if you show a FREE Chlorine level of 7 on a regular basis.
 
Thanks guys for the quick responses. I agree with you it seems like chlorine (I have spent quite some time reading the stickies I here over the last year or so) it's just the test tell me otherwise so I am confused.

To summarise I have had 2 water tests over the last 2 weeks. First indicated slightly low salt and high ph. So was just a bit of salt and acid to add. Nothing major.

Anyway I will post results below of the test. These are from my local pool shop which I use sparingly as a guide as their test equipment is far better than what I have at home. It does t cost me anything and I have been using them for a couple of years.

Alkalinity 125
PH 7.5
Calcium 225
Salt 6200
Stabiliser or CYA 61
Iron 0.3
Copper 0.0

chlorine test#1. Free 6.35 total 6.59
Chlorine test#2 free 10.3 total 11.1

I also tested with my home kit for chlorine, it shows over 6ppm, which is the max it goes to. So that's three reading showing it is high. The pool is crystal clear otherwise, went for a swim today and it doesn't smell of chlorine at all which with a reading over 10 I would have thought it would be pretty noticeable.

Thanks
 
Pool stores around here are VERY bad on the CYA test as well as the others. I took my water to 3 different pool stores and got three different results! It was the same water from the same spot at the same time. The only difference was the pool stores. I had tested the water at home and it was right where it should be and looked great!

Please consider buying a GOOD test kit. Here is the link to show you them
http://www.troublefreepool.com/content/124-pool-test-kits-comparison

Having your own good test kit will be the best way for YOU to take control of your pool and overcome the green monster.

Kim
 
Those numbers should give you an algae free pool. Keep your FC up above 4 ppm at all times.

Brush away the existing algae and if it reappears, you must SLAM your pool. The article on how to do that is in Pool School.

I cannot answer why you have algae.........there is no "miracle" algae that will not succumb to adequate chlorine

(Your pH is not slightly high, it is perfect. Review the ranges for all your tests in Pool School)
 
Thanks again, in the short term I might try another shop to test the water, and see what results I get.

I've been thinking of a tf100 kit for a while, just the freight costs to us her in Oz is a killer. Wife might be in the States later in the year so that might be the time.

Cheers
 
Welcome to TFP !
Just one thing I can add is the algae may be forming in certain areas that are receiving poor water circulation. Even in a pool with proper FC levels for the CYA level algae can sometimes still form in places that are not seeing adequate circulation. Those areas would need to be brushed often to prevent algae from forming there.
Now with that said I'm very suspect of the pool store testing of the CYA level. They're not that good at it and it is the key level, as that sets your FC range. You need a good test kit to get an accurate read on where the CYA level is.
If the algae is still returning a SLAM will be needed to totally eliminate the algae. That's the only way to rid the pool of it. To SLAM the pool you will need a good test kit.
If you could add all your pool and equipment info to your sig that will help us help you better. Thanks.
Keep us posted on how things are going.
 

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"Pool stores around here are VERY bad on the CYA test".............THAT statement is probably a large contributor to your problem. Some of the reason being that the test is conducted inside under artificial light instead of outside in natural light to help explain it for you as to why.
 
I would suspect that you might have multiple issues. You might have some mustard algae, and I think that you might have some iron precipitating. I think that what you are seeing on the fittings is more likely to be iron stains.

As the iron goes through the cell while it is producing chlorine, the chlorine oxidizes the iron and then the high ph causes it to form insoluble compounds and precipitate.

Does any of what you're seeing have any yellow or brown color?

You can test for iron by putting some crushed vitamin C (ascorbic acid) on a spot to see if the spot clears.

Also, your alkalinity at 125 is high for a salt pool. I would suspect that your pH is constantly rising and is occasionally over 7.8. If that is the case, lowering the TA (total alkalinity) would help.
 
JamesW said:
I would suspect that you might have multiple issues. You might have some mustard algae, and I think that you might have some iron precipitating. I think that what you are seeing on the fittings is more likely to be iron stains.

As the iron goes through the cell while it is producing chlorine, the chlorine oxidizes the iron and then the high ph causes it to form insoluble compounds and precipitate.

Does any of what you're seeing have any yellow or brown color?

You can test for iron by putting some crushed vitamin C (ascorbic acid) on a spot to see if the spot clears.

Also, your alkalinity at 125 is high for a salt pool. I would suspect that your pH is constantly rising and is occasionally over 7.8. If that is the case, lowering the TA (total alkalinity) would help.
Click to expand...

Thanks but it's definitely not Iron, it's dark green algae and as a poster mentioned above it shows in areas of the pool that may get low circulation. I.e. Corners of the pool. A quick brush disperses it , Also test results show no issues with iron content.

I had added some acid of late as per my early post alkalinity and ph. was reported as high. My pool shop recommended no more than a 7.0 to 7.4 range for ph and 80 to 140 for alkalinity. Both of those though I admit have gone above those ranges at times.

I will take the advice of keeping a close eye and brushing those corners more regularly, it is strange as I had this problem start around the same time last year. It got to a stage where Algae was all over the pool walls, not just the corners so I did have to SLAM the pool back then (I followed the instructions from on here)

could water temp have anything to do with it? We certainly have a high bathing load at the moment as well.
 
Yes water temp can affect your FC. You'll lose more than normal FC per day at higher water temps. High bather load will also contribute to losing more FC per day.
To have algae forming all over your pool walls and not just in corners last year, suggests your FC levels are dropping below the minimum for your CYA level. Remember the higher water temp and bather load is affecting how much FC is loss during the day. You need to compensate for that on those types of days.
How long are you running your pump per day and what is the SWG percentage set at ? You should also be brushing the pool at least once a week.
Also for a SWG we recommend having your CYA level in the 70-80 ppm range. This range will help protect your FC better. Here again the pool store testing of the current CYA level could be off. This is why it would be in your best interest to get a good test kit to verify what the actual CYA level is.
 
kimkats said:
Also take your light out and see what is in there. Many a pool has green yuckies inside the pool light. Also think about ladders and such that might be hiding some stuff.

Kim
Click to expand...

Good thinking. I have noticed that dirty / algae type appearance under the pool light front cover. Not extreme but it's dirty enough to notice and no where near perfectly clear. I will pull it out and give it a good clean.

Might that enough to maybe be causing these small bits of algae in the rest of the pool?

EDIT
I pulled the light cover off, there was a small bit of green algae at the bottom behind the front clear Perspex but nothing else behind the light. Again a small amount but clearly visible as algae.
Also spent a bit of time in the pool, today and by the end I could tell the chlorine was too high, sore eyes and kids complained of it too. I've turned my SWG down a notch to 4 and will leave the pool blanket off for a few days to drop the level. Still strange how that algae is appearing with such high levels of chlorine though.
 
Last edited:
I have to say that my husband complained more about the eyes when the PH was off.

The little bit in the light is part of the problem. The BIGGEST part of the problem is the balance of your water.

IF your water is balanced according to TFP charts you should not have algae. You will have to SLAM to get it there. In order to really SLAM you need a good test kit.

If you have a ladder make sure to brush the underside of it as well.

Kim
 
You need to brush and SLAM your pool. If algae is present, you do not have enough chlorine even though you say it's high. It's not high enough for a long enough period of time.
 
Well since I brushed last week the algae in the corners hasn't reappeared. Also the problem we had with sore eyes has gone away also. So fingers crossed.

That said I am going to take your advice a buy one of the Taylor's kits. The 2006 I think?
Only question I had is do the reagents have a shelf life? Being I am in Oz, I am thinking it may pay to stock up on some reagents to save shipping costs.

Also if I do (and can) stock up what items would you suggest I get more of?

Thanks
 

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