Pool Algae Problem Support - READ FIRST

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
COSTAS

Pool Algae Problem Support - READ FIRST

Postby COSTAS » Mon 02 May, 2011 17:22

I have a pool and become green and cloudy . When i checked the level of chlorine i find out that the chlorine disapire sudenly from the water. I add a lot of chlorine but no changment.the level of ph was a little high. The next day i add acid because i beleive was i lot of free chlorine in the water ( the tester show high chlorine) but nothing change.now i have a swimming pool with green and cloudy water and the tester show too much chlorine and too much acid.
The same proplem i had also last year the same time.few days sun shine and start this problem.
I wondering as around the pool there are a lot of tree and flowers if any of these trees give problem to the water as now start the spring .
I dont know what to do.add more chlorine(superchlorination) add more acid as i done once in a swimming pool with same problems ( within 24 hours the water become crystal) or i add soda ash for incrwase the ph.
Note that is a big pool arround 200,ooo litres water and i add since now 50 kg acid and 10 kg chlorine

thank in advance
best regards
costas ioannou ( cyprus)


chem geek
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Pool Algae Problem Support - READ FIRST

Postby chem geek » Mon 02 May, 2011 19:43

Do you know the Cyanuric Acid (CYA aka stabilizer or conditioner) level in the pool?

If it's a cloudy green, it's likely to be algae (a clear green would be more likely to be metals). Chlorine will kill the algae, but if the CYA level is too high then it will take an extraordinarily high FC level to do so. Lowering the CYA level would be the best long-term solution since you'd have to do that at some point anyway.
Swimsim

Pool Algae Problem Support - READ FIRST

Postby Swimsim » Thu 02 Jun, 2011 03:57

Hi Larry,

Righto here goes...
I have a above ground Intex pool, left water in over the winter, teenage sons who think they know best half emptied the pool in March then refilled it and plopped a tub of our usual floating chlorine and surprise surprise the algae stayed in the pool!!!!

Now I have tried my best to get rid of the algae - wont bore you with the details as reading the forums I have wasted my pennies and did it all wrong!!! :(

Have now empited the pool, all bits & pool have been cleaned (by me this time) and I have about 5 " of water left in the bottom with some algae still laying loose - question is what do I do now???
1. Refill & plop our floating chlorine in & that will get rid of the algae (as there isn't alot) ??
2. Put some 'shock treatment' in the remaining water ??
3. Fill up pool & put some shock treatment in the pool ??

All advise will be most welcomed as the weather has alast turned nice & summer like.

Thankyou 8)
chem geek
Pool Industry Leader
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Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Pool Algae Problem Support - READ FIRST

Postby chem geek » Thu 02 Jun, 2011 13:05

Physically remove whatever algae you can since that will make things easier. Then, fill up the pool. You can add some chlorine to it as it is filling up. Easiest chlorine to use to start with would be Dichlor since it dissolves quickly and adds both chlorine and CYA, but you don't want to use too much. You would then use chlorinating liquid or bleach to shock the pool to a higher chlorine level -- around 40% of the CYA level. That should kill off the algae. Read Defeating Algae .
Kurt H

Pool Algae Problem Support - Salt Water

Postby Kurt H » Sat 25 Jun, 2011 21:54

Problem: Trying salt for first time. Pool has been set up for only 2 weeks. Just noticed green water and significant visual algae today, but has probably been growing for 3-4 days. I do not have a chlorinator - is there another method of chlorinating? Can I simply add chlorine (bleach) to salt water? I Will check pH and FC levels before chlorinating.

FC:
TC:
pH:
TA:
CH:
CYA:

My pool: Intex 18' dia. x 48" deep
Pool chemicals: 160 lbs. salt
My pump & filter: Intex with size A filter
Other info:
chem geek
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Pool Algae Problem Support - Salt Water

Postby chem geek » Mon 27 Jun, 2011 21:37

Kurt H wrote:Can I simply add chlorine (bleach) to salt water?

Yes, absolutely you can use chlorinating liquid or 6% unscented bleach. However, since this sounds like a fresh fill of water, you should have some Cyanuric Acid (aka stabilizer or conditioner) in the water. If you don't, then either get some pure CYA or use Dichlor as your source of chlorine for a short while. For every 10 ppm Free Chlorine (FC) added by Dichlor, it will also increase Cyanuric Acid (CYA) by 9 ppm. So after you've cumulatively added around 33 ppm FC or so from Dichlor, you can switch to using bleach or chlorinating liquid (or keep using Dichlor a bit longer but use a higher FC target). See the Chlorine / CYA Chart for the FC level you need to maintain at each CYA level to prevent algae growth and maintain a disinfected pool.
Ralph W.

Pool Algae Problem Support - READ FIRST

Postby Ralph W. » Tue 28 Jun, 2011 21:32

Also get the phosphate level down in your pool. High phosphate levels will encourage algae growth even if the chlorine is high. You can get liquid phosphate removers that will bring the level down to levels where you'll rarely see algae even at modest chlorine levels.
chem geek
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Pool Algae Problem Support - READ FIRST

Postby chem geek » Wed 29 Jun, 2011 08:59

A phosphate remover needs to be seen in the same vein as an algaecide. While a lower phosphate level will slow down algae growth, it is not necessary if one maintains the appropriate FC level relative to their CYA level. I had over 3000 ppb phosphates in my pool and kept it algae free by simply keeping the FC at least 7.5% of the CYA level as have others, some with 5000 ppb phosphates. Chlorine alone can kill algae faster than it can grow regardless of algae nutrient level (phosphates, nitrates). This is because algae growth is ultimately limited by sunlight and temperature with a growth doubling rate of 3-8 hours.

Also note that phosphate removers do not remove organic phosphates, only inorganic phosphate (orthophosphate). While algae uptake of organic phosphates is slower, bacteria can convert organic phosphate to orthophosphate so if you let the chlorine level get to zero, then you can still get algae in your pool in spite of having a phosphate remover and we've seen reports of that on multiple forums.

There is no question that at high phosphate and nitrate levels that a pool is much more "reactive" in that letting the active chlorine level (FC/CYA ratio) get to low has algae grow faster, but it is absolutely not true that you can't prevent algae growth with chlorine alone. You can, and many do -- in fact, tens of thousands of pool owners at this forum, The PoolForum , Trouble Free Pool and elsewhere.

So if one wants to have insurance or a lower than required chlorine level, then yes one can spend more money for a phosphate remover or use PolyQuat 60 algaecide weekly or add 50 ppm Borates to their pool. All are effective methods, but not complete protection (i.e. algae can still grow if the chlorine gets very low or to zero). Copper-based algaecides also work, but can stain pool surfaces and make blond hair turn greenish. So there are options, but I would not say that a phosphate remover is at all required since chlorine alone can prevent algae growth if one understands the chlorine / CYA relationship and maintains the appropriate FC/CYA ratio.
joywil

Pool Algae Problem Support - READ FIRST

Postby joywil » Sat 06 Aug, 2011 12:51

•Problem: The algae problem , we have had this problem every year , we have trees about 20 feet from our pool
•FC: free chlorine level 0
•TC: total chlorine level 0.3
•pH: 7.4
•TA: total alkalinity level 109
•CH: calcium hardness level
•CYA: cyanuric acid level (stabilizer / conditioner)
•My pool: above ground, 27 ft,
•Pool chemicals: the chemicals you use for pool maintenance (chlorine, bromine, ...)
•My pump & filter:
•Other info: temp 77, bather load used very little due to the alge, abnormal weather : we have had a lot of rain or environmental factors and trees in our backyard
Bridget

Pool Algae Problem Support - READ FIRST

Postby Bridget » Mon 14 May, 2012 06:27

Hi

We recently re-marblited our pool and ever since then the water has been green. After the first couple of times it responded to the chemicals given us to return it to blue and now nothing happens. The PH and Chlorine readings are in the normal.

We have even employed a pool company to assist and after a month it is still green.

Please help

Bridget

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