dark green pool - how do I clean it??

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
chem geek
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dark green pool - how do I clean it??

Postby chem geek » Tue 12 May, 2009 09:42

You don't just dump in some chlorine -- it takes a lot. If the CYA level of 40 ppm is correct (you REALLY should get your own good test kit), then you should maintain an FC level of 16 ppm or so, brush the pool, keep the pump on, add more chlorine as the FC drops. The pool WILL clear. See this link for a messy pool that got cleared up with chlorine alone. Read the Defeating Algae link and follow its instructions.


bobbyg714
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Dark green pool - how do I clean it??

Postby bobbyg714 » Tue 12 May, 2009 09:53

Ordered the test kit this morning per your other post. The original test was done by leslies. I have the pool place around the corner from my house testing the water again after I get home from work. And will do so every day to ensure I keep the prper FC level. I will also pick up another 5 gallons of the liquid chlorine. I am looking at the number of 16 you provided and assume you want me to keep the FC level at 40% of the CYA? Thank you again.
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Dark green pool - how do I clean it??

Postby bobbyg714 » Tue 12 May, 2009 15:41

Richard,
Took a sample of pool water from 10 am this morning to a different pool place. They had a test kit that was computerized and fed results to a computer for printing. They were different from the Leslie readings. Here is what they said:

FC 6.9
TC 6.9
Com C 0
PH 7.4
TA 60
CYA 15
Copper 0
iron 0

The pool looks no clearer than before. I am going to add some more liquid chlorine. Any suggestions on what I should do to see any difference. Please help if you can. Thnak you. I am confused as to why the difference in test results.

Bob
chem geek
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dark green pool - how do I clean it??

Postby chem geek » Wed 13 May, 2009 01:14

If you had your own good test kit then that would be better. Some pool stores do not do tests accurately or correctly. I'm not sure why you didn't order the tests I suggested (either the Taylor K-2006 or the TF100).

If your pool does not have a floor drain so has poor circulation, then you can use a flocculant as I suggested and then vacuum-to-waste. Make sure all the algae is dead first -- the water should be cloudy, not green.
bobbyg714
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Dark green pool - how do I clean it??

Postby bobbyg714 » Wed 13 May, 2009 04:55

Richard,

I DID order the kit you suggested yesterday morning so I am waiting for that to arrive. It is still very green this morning. I had added another 5 gals of liquid chlorine last night but it looks no different today. I will be switching out the filter to a DE filter on Saturday. I am hopping that helps to clear this up. I will test water again on Thursday and post the numbers.
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Dark green pool - how do I clean it??

Postby Me... » Wed 13 May, 2009 08:13

I didnt read what filter you presently have or even the size of it in relation to your pool. But, swapping filter choices will not help an algae problem un less the existing filter is broken.
bobbyg714
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Dark green pool - how do I clean it??

Postby bobbyg714 » Wed 13 May, 2009 09:52

I currently have a Hayward sand filter I think S200. My poll is 23000 gallons. Pump Is 3/4 Hp (I think) I am wondering if the filter is also having an issue and not keeping up. I have put 10 gallons of liquid chlorine in the pool over 2 days and I am brushing, and backwashing like I have been told. I am really confused as to why I got two way different readings from 2 separate pool places especially the CYA level. I have been following the instructions from Chem Geek to a T and I ordered my own test kit that he recommended but it hasn't gotten here yet. Pool was still a dark green this morning before I left for work. Even though I can't see the bottom I did do a quick vacuum to waste last night to try and get any leaves and piles of algae out. I then added another 5 gallons of 12.5 % liquid chlorine.

The one number I was concerned with was the TA of 60 compared to the 100+ number the other place provided. Does that need to come up to kill the Algae?
Guest

Dark green pool - how do I clean it??

Postby Guest » Wed 13 May, 2009 10:45

We had the same problem, our pool shop had us adding acid, make sure that level is in the middle before adding Chlorine or the Chlorine won't take effect. We had to add over a gallon of acid ...
bobbyg714
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Dark green pool - how do I clean it??

Postby bobbyg714 » Wed 13 May, 2009 14:51

Are you talikng about the TA level?
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dark green pool - how do I clean it??

Postby chem geek » Thu 14 May, 2009 03:24

BobbyG,

The TA won't affect how you kill the algae, but having it a little higher (say, 80 ppm) will help a little with pH buffering from the added chlorine. It's not a big deal at this point, however.

You said you added 10 gallons of liquid chlorine and saw no difference in the pool. That should have raised the FC level by 27 ppm. Have you been able to measure the FC level? Remember that from Defeating Algae you need to maintain a high chlorine level, not just dump some in. If the FC drops, more chlorine is to be added to keep it higher.

Take a look at the sequence in this thread which is how a pool usually clears up from algae when using chlorine alone but hitting it hard and consistently (but that pool has a floor drain).

Richard

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