Second season with Algea - help

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SingingSailor

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LifeTime Supporter
Aug 14, 2008
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Trollhättan, Sweden
Just like last year, I now have algea problem at the end of the season.

Have read "pool school" and some posts on the subject, and have a few questions:

- Is it common to have a very low chlorine consumption during an algea bloom? (My chlorine consumption last week has been 1ppm/24h).
- Can algea continue to grow at chlorine levels above "Yel/mstrd min" level? (Last year this seems to be my experience).

10 days ago I saw some algea growth. The water also got a faint plastic smell. Did a normal shock treatment, and thought it was ok.
Today, the bottom and walls were covered by a thin greenish layer. It is very easily brushed off into a browny cloud.

Current situation, before shocking:
FC 1,5
CC 0
pH 7,5
CYA about 25

I shocked with about 300g of calc hypo, and brushed the pool. Three hours later I have FC = 16 ppm. 300g should raise FC with 13ppm in my pool. I obviously took a little more, but it seems again that my "algea" doesn´t consume any FC. Is this normal?
Will do the OCLT tomorrow morning.

Here's my topic from last season:
http://www.troublefreepool.com/have-i-got-green-algae-t37534.html

Appreciate any help.
 
If you have visible algae you need to maintain shock level and follow the shock process in Pool School.

It is a little odd you are not seeing more of a FC drop, no you have any type of automatic chlorine addition?

Some algae has a biofilm that must be broken by brush so that the chlorine can attack it. That would be the only way it would survive above shock levels.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
No automatic chlorination. Only manually added (trichlor, dichlor and calc.hypo).

Measured today at 17.00 with TF-100:
CYA below 20 (lower than expected)
FC 15,5 - still above "mustard shock level", and no chlorine added since the 300g calc.hypo yesterday afternoon.

Algea is still growing :grrrr: Slowly, but still. There are some small areas with deposits / algea on the bottom and on very thin threads hanging out from the liner walls in the corners. I could possibly have missed some spots when I brushed yesterday, but I´m sure I didn´t miss the threads.

Note on CYA level: Measured below 20ppm 10 days ago, but have added some since, therefore noted 25 in last post. Measured today, dot disappears only with completely filled tube => CYA < 20ppm. I have kept good logbook on chlorine this season, and I have added tri and dichlor that together should have given 40ppm CYA (since the startup with fresh water). It seems to me that I should trust the measured value more though. What do you think?

Something is growing, even at FC well above shock level, and I have very low chlorine consumption.
This is exactly the same story as last season, and also starting at almost exactly the same date.
What is this? :cry:
 

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Ok, good that you have a nice kit.

From you first post, you clearly let the FC drop too low. That allows the algae to start. Once it starts, you have to go through the Shocking Your Pool process until you pass the 3 tests.

Your CYA level is a bit low, and at 20ppm, your shock level is only 10ppm. You do not want to be maintaining the FC level over mustard shock level as that could lead to liner fading. Stay closer to 10ppm and brush the pool down everywhere you see the algae.

After your complete the process, raise the CYA up to around 30ppm and then never let the FC below 2ppm ... try to keep it up around 4ppm.
 
Thanks for you help, Jason.

Either I don't get it right with the Shocking your pool process, or it doesn't work in this case.
The three tests:
- CC is 0.5 or lower: Always below 0,5 this season
- An overnight FC loss test shows a loss of 1.0 ppm or less: I have a loss at or below 1ppm over 24 hours! Even during high algea growth!
- And the water is clear. The algea grows on the bottom and sides, but the water is clear until I brush the sides and stir up a cloud of algea. The water clears after about 2 days, but the algea still grows on bottom and sides.

In my journal from last season I see that I had algea growth even with FC as high as 20ppm (with CYA 40ppm).

Had an old bottle of algeacide at home (polyquat I think), and will try that now.
 
The 3rd test ... clear water ... includes not being able to see any algae ... so that is clearly failed at this point.

I am not sure how it is possible that you are only loosing 1ppm of FC in a day with such low CYA ... that just does not make sense to me even if you did not have visible algae as the sun would break it down.

Make sure the algaecide does not contain copper ... also realize that algaecide is usually for prevention of algae, not killing it.
 
Ok, thanks for the clarification on clear water. No, I don´t pass that test :( . Last season I had some algae growth from beginning of August till closure in mid september...

I always keep the pool covered by a blue solar blanket, day and night. This can explain the low loss of chlorine?

I don´t think there´s any copper in this one. Main drawback of copper is staining, is it?
I knew it´s not really for killing algea, but I hope it will help stopping regrowth once I get the worst under control.
 

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Ah, yeah the cover could explain the lower FC loss.

I suggest continuing the shock process until the algae is no longer visible (and the other 2 tests are ok). Then maintain adequate FC (you fell a little short in your first post).
 
6th day of shocking - still growing

I still have some algea growth on the 6th day, although very little know. Is it normal that is takes this long to kill it?

Here´s my logbook:
15/8 19.00 pH=7,5 FC=1,5 CC=0 Visible algea on bottom and sides (started growing a little a week earlier). Brushed. Added 300g calc.hypo.
  • 22.00 FC=16
16/8 06.00 FC=16,5 CC=0
  • 17.00 FC=15,5 CYA=20 (or less) Brushed.
  • 21.00 Added 50ml polyquat.
17/8 06.00 FC=12,5
  • 11.00 Clear water, some visible growth on sides. Brushed => brown cloud visible in some areas.
  • 24.00 FC=9,5
18/8 08.00 FC 9,0 CC=0,5 Added 70g calc.hypo (eq. 3ppm FC)
  • 12.00 Clear water. Some growth on sides. Brushed => brown cloud, but less than day before.
  • 22.00 FC=12 CC=0,5
19/8 15.00 Brushed. Same situation as day before
  • 19.30 FC=10,5 CC=0,5
20/8 06.00 FC=9 CC=0 Added 100g calc.hypo (eq. 4,5ppm FC)
  • 21.00 FC=12.5 CC=0,5 (very faint) Brushed. Still some growth, but very little, less than day before.

Total chlorine consumption since beginning: (16-12.5)+3+4.5=11ppm, that is about 2ppm per day (incl. possible effect of added polyquat).

Questions:
- I read in this forum that polyquat is broken down by chlorine. I added 50ml day 2 - is it likely to have affected my chlorine consumption? Does it form combined chlorine when it is broken down?
- I read in pool school about mustard algea: "Another way to distinguish between the two is that when you go up to shock level and brush the pool, mustard algae won't come back as long as you stay at shock level". I´ve been at shock level continuosly and brushing for 5 days, and it still grows. Is this normal?

Hopefully I will not see any more growth when I brush tomorrow. What do you recommend me to do next? Shall I raise FC even higher a last time, and "decontaminate" toys etc as described under "mustard algea", or is it not necessary?
 
Bama Rambler said:
Understanding that you're located in Sweden, how are you testing?
Click to expand...
I´m using the TF-100. When I had algea problems last year I got help from a friend to bring a test kit back to Sweden from the USA, since it can´t be bought in or shipped to Sweden.

Bama Rambler said:
If you're holding shock level for your CYA almost constantly you shouldn't be seeing any living algae.
Click to expand...
Yes, that is also how I interpret the pool school, and this is the KEY issue for me. But for me algea DOES GROW at FC held constantly well above shock level for several days! And I had the exact same situation last season.

Appreciate help on this.
 
Since what you are describing is outside the realm of anyone's experience here on the forum, it is pretty tough to offer any dependable advice.....just some guesses.

You might drain the pool, spray it down using something like a 10:1 water/clorox mix, hose it off fairly quickly and refill. That is only a guess and it may fade that liner but I have no other ideas.

Monopersulfate, MPS (if you can get it) is a powerful oxidizer that may not harm your liner but it is out of my experience level. Others may have another idea.
 
To Duraleigh: Ok. I greatly appreciate the answers from all of you!
Very near end of season now, but will try spraying the liner when I refill next spring.
Odd though that I should have stumbled upon a situation not seen before, more likely after all that I´m doing something wrong or interpreting wrong.


Bama Rambler said:
Are you sure it's algae and not something in the environment?
Click to expand...
No, I can´t be 100% sure. My "algea" experience is limited to what I´ve seen now and last season. It does though "grow" or deposit on all surfaces, first visible on the thin threads hanging out from the wall. It is green / yellow in colour, turns into a yellow/brownish dust cloud when brushed. The cloth I brush with gets brown. The filter cartridge gets dark green when I have this problem (but not otherwise).
The water also has a light smell, a bit like "plastic" - but I don´t know if it is connected with the algea problem. I would be grateful if someone have another possible explanation.

Bama Rambler said:
Since you have the TF-100 you can, and should, run the OCLT.
Click to expand...
That´s what I thought I´ve been doing several times? Overnight Free Chlorine loss has been below 1 ppm all the time, whith one exception. The exception could be connected to the polyquat that I added?
Does anyone know how much chlorine consumption can be expected from 50ml of polyquat?
 
Hmmmmm. If you are not using any chlorine overnight, then it would indicate whatever is "growing" is not really organic but inorganic material that is accumulating in your pool.

What kind of liner is that? Anything else you can think of in your pool that might be "shedding" inorganic material.

Any possibility this material may be coming from the atmosphere?

That the material is inorganic is a far better possibility than anything alive growing in your pool.
 

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