Another Green Pool HELP

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

Another Green Pool HELP

Postby Debula » Tue 21 Apr, 2009 19:20

Since I didn't get a reply in the other thread I thought I should post this in a new topic (sorry I need help)

Hi, I hope you can help us too!!
We have an above ground vinyl pool. We have neglected it during the winter and now we have a green pool
Most of the stuff we sucked up from the bottom was dust and pollen but now the bottom is green and it will not brush up. My husband has been shocking it for 2 days and yet the chlorine level is still zero
We went to the pool supply place today and got two conflicting stories
The fist guy told us to go home and get a sample because if it was calcium then the algaecide (sp?)would not work
and he told us if that is the case we need to just add acid and it will soften the calcium and loosen the algae.
We took the sample back and there was another guy there and he sold my husband the algaecide and told him to shock and throw in the algaecide and within a couple of hours we should be able to brush it off
It didn't work and the bottom is hard where the green is and it won't brush off
The levels they gave us are as follows
Chlorine 0
PH 7.6
Alkalinity 70.80
Conditioner 0
Calcium Hardness---------- (that what he did just a line)
TDS Meter 800
Phosphate 0.100
Salt-------- (another line)
Our filtration system is what came with the pool and is a cartridge filter
The pool is about a 6500 gallon pool (18ft round about 48 inches high)

What I don't understand is how two people from the same store can give us such conflicting info
That seems to be the norm and our experience depending on who you ask and its soooooooooooo frustrating :x

PLease help!! Also please explain in easy terms and I don't understand all the pool tech lingo :crazy:


chem geek
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Another Green Pool HELP

Postby chem geek » Tue 21 Apr, 2009 20:00

1) Get a good test kit -- read this for good ones.

2) Read and follow Defeating Algae .

If you are just opening the pool and you had CYA in the water before you closed but now it's gone, then it can take a LOT of chlorine before the chlorine starts to hold. Add 10 ppm FC at a time until it starts to hold, and then you can balance the rest of the water. But order the test kit right away.
Pooltech32
Swimming Pool Wizard
Swimming Pool Wizard
Posts: 75
Joined: Thu 06 Jul, 2006 20:43

Another Green Pool HELP

Postby Pooltech32 » Tue 21 Apr, 2009 20:01

Ok lets see if I can help you, first of all what kind of chlorine do you use most of the time? chlorine pucks, granular, liquid?
When a pool turns green the algea consumes tons of chlorine, when you shock the pool test it 30 minuntes later to see if you are getting any kind of reading, if not then you may have a stabilzer problem.

For a green pool I would start with liquid chlorine, generally I would add about 30-40 liters of 12% bleach, now the company that tested your pool said you had a conditioner reading of 0? that would meen that the chlorine is being burnt off by the sun really fast, where do you live? do you gets lots of sun? If the readings are correct you need to get your stabilizer up to about 35, then you will not be wasting chlorine and money.
I am pretty sure that will fix your problem. if not you have another issue.
Pool repair guy
Debula

Another Green Pool HELP

Postby Debula » Tue 21 Apr, 2009 21:53

Hi guys and thanks for the replies
I have to admit I am pretty dumb when it comes to pool lingo so
When you say CYA what does that mean?
What is pps?
Where do you get 12% bleach?? My launry bleach says 6% of something
We have been using liquid chlorine from the pool supply place
after shocking it two times with granule shock. We have put in 1 gallon liquid yesterday and one more gallon today. We even added acid like the first guy told us since the chlorine didn't seem to help.
About the stabilizer ..is that the conditioner?
Please bear with me here while I understand this very complex pool science chemistry

All of your help is GREATLY appreciated

in the meantime I hope stabilizer is conditioner so we are going to add that now
We live in CA and are in the middle of a record breaking heatwave at the moment
Also won't all these chemicals/chlorine in such massive amounts eat my poor vinyl pool?
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Another Green Pool HELP

Postby chem geek » Wed 22 Apr, 2009 02:10

CYA stands for Cyanuric Acid also known as stabilizer or conditioner.
"ppm" is parts-per-million and is the measurement for most of the water parameters (pretty much all of them except for pH). You can read more about Definitions and Abbreviations .
Bleach is usually 6% (Clorox Regular or off-brand Ultra). It is chlorinating liquid that is 10% or 12.5% or thereabouts. They are the same except for strength. You can get chlorinating liquid at some pool stores, hardware stores and big-box stores.

The granular shock you are using could be calcium hypochlorite (Cal-Hypo). If it is, then for every 10 ppm Free Chlorine (FC) you add, it also increases Calcium Hardness (CH) by 7 ppm. The granular shock could instead be Dichlor. If it is, then for every 10 ppm Free Chlorine (FC) you add, it also increases Cyanuric Acid (CYA) by 9 ppm. If you are properly maintaining your pool's chlorine level, you rarely need to shock the pool.

As Pooltech32 noted, part of the problem with your pool could be that there is no conditioner/stabilizer/CYA in it. In that case, in direct noontime sun, half of the chlorine can break down every 35 minutes. So add some (but not too much) conditioner/stabilizer/CYA -- enough to get to around 30 ppm. You can use The Pool Calculator to figure out dosing. For 6500 gallons, 30 ppm CYA is 26 ounces weight of conditioner/stabilizer/CYA.

As for chlorine, 30-40 liters of 12% chlorinating liquid in 6500 gallons would be way, way too much chlorine. 3-4 liters or around one gallon would be fine to start with as that's close to 20 ppm FC. Then measure in 30 minutes to an hour and add more chlorine if it's dropped. With 30 ppm CYA you'll want to keep a minimum FC of at least 12 ppm.

These chemicals are safe to add to your vinyl pool if, for the chlorine, you add it slowly over a return flow with the pump running. For extra safety, you can lightly brush the side and bottom of the pool where you add it to ensure thorough mixing. For the CYA, it dissolves slowly and can be added slowly into the skimmer and it will slowly dissolve in your filter so keep the pump running. Another alternative for getting CYA into the water and chlorine at the same time is to use Dichlor granular/powder as this dissolves quickly. For your size pool you'd use a little more than 3 pounds of Dichlor, adding half that amount, measuring the chlorine in 30-60 minutes, then adding more as needed until you use up the 3 pounds. After that, switch to using bleach or chlorinating liquid.
Pooltech32
Swimming Pool Wizard
Swimming Pool Wizard
Posts: 75
Joined: Thu 06 Jul, 2006 20:43

Another Green Pool HELP

Postby Pooltech32 » Wed 22 Apr, 2009 18:57

ok I saw 65,000 gallons sorry, not 6500 gallons!! :crazy:
Pool repair guy

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