Copper in water - ok to use bleach?

I’ve read most of the posts on this forum about using bleach; and I think I’m ready to give that a try. I've been battling a chlorine "demand" with calcium based shock and dichlor (not at the same time, of course); and recently saw some green algae appearing in places. I've been putting 2 lbs of shock in my 16,000 gallon pool every day since June because the chlorine won't hold. The CYA reading was always in range (water tested once a week). Anyway, a couple of days ago I used a whole bottle of algaecide plus and a whole bottle of mustard algae killer at my pool company’s recommendation. So here’s my question: will the copper that the algaecides put in the water cause a problem if I shock with bleach? We got about 3 inches of rain last night, so the water has been diluted some.

All algaecides aren't copper based. You really need some good numbers. In range doesn't say much. Pool stores will tell you CYA is low at 100, which is in reality way too high. Post some water chemistry numbers and how you got them and we can get you straightened out.

While you are having your water tested - also have them test for copper since you are worried - just don't buy anything. I saw a guy in the pool store this weekend with a similiar problem and they wouldn't let him out of there without over $100 in unnecessary chemicals.

OK, I've got some numbers here. I know that not all algaecides have copper in them, but the one that I used did (3.3% I believe). I don't have a reading on the copper, though, but the water was a light purple when it was tested. They just didn't have the necessary stuff to read the results, I guess. I put 4 lbs of dichlor in last night, and got the water sample this morning. Here's what the analysis says:

CYA 146
TC 8.5
FC 6
ph 6.6 (this was 7.8 3 days ago)
TA 69
Sat. Index -1.2

Your most immediate concern is your ph level. How could it have been 7.8 three days ago and now at 6.6? Have you added any muriatic acid? Did you pull your water sample off the top of the pool after rain before your pump had been running and circulating the water? If it is indeed 6.6, you need to add some Borax ASAP. Readings below 7.0 are acidic and can damage your pool. Also, your cya is sky high at 146. We recommend 30-50. How long have you been using dichlor? Have you used any trichlor pucks? With cya that high, you have two choices. One - you can do a partial drain and lower it. In your case, you'ld probably have to do a partial drain several times. Choice two - live with cya that high, but as a result you'll have to run much higher than normal chlorine levels. I'm sure that is why you are having algae problems because pool stores don't seem to know to tell people that if your cya is really high, your chlorine level must be also or else you get algae. Take a look at the sticky at the top of the chlorine forum called "best guess table." No more trichlor or dichlor for you. Both will cause your cya to continue to climb. Since you don't report your calcium hardness level or tell what type of pool it is, I can't recommend using cal-hypo. Bleach is your best bet for your source of chlorine.

Thanks for the reply. Sorry that I left out some pertinent info. It's a vinyl pool, 16 x 32. All summer I've not been able to keep chlorine in it, despite shocking every Sunday with the recommended 2 pounds and shocking every day in between with 1 to 2 pounds. I've been using dichlor for 2 1/2 weeks; prior to that I used calcium based. I'm not sure at all how the pH could have dropped so much. All I put in was the 2 bottles of algaecide (one with copper) and a total of 6 pounds of dichlor. The pump has been running 24/7 since I put the algaecide in. I didn't get the water samples off the top - I got them from about 10 inches deep. I had about 4-5 pounds of balance pack 100, so I just put that in to raise the alkalinity. I've not used any trichlor pucks. I don't have the past test sheets, but the CYA has not been that high until recently. Could the dichlor have done that? As I said, I've put a ton of shock in this pool in the last 6 weeks. The total hardness (I guess that is calcium hardness?) is 340.

Should I wait until the copper level has dropped to put the bleach in? I plan on getting another reading tomorrow, but they use Alex and don't have a way to gauge the copper reading.I tested the ph just now with drops and it appears to be right at 7.2, but that's with the cheap tester. I will get a good one soon! Assuming that the demand has finally been met (which may not be a good assumption), do I still need to keep the chlorine high for a while to take care of the algae? I have not seen any more; but I don't know when a safe period of time is to assume that it's cleared up.

Thanks for the help!

I have one more question - on the best guess CYA chart - what is the difference between FC and Shock FC? Should I aim for somewhere between min and max FC or Shock FC?

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Originally Posted by mccato

I have one more question - on the best guess CYA chart - what is the difference between FC and Shock FC? Should I aim for somewhere between min and max FC or Shock FC?

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Min FC and MAX FC would be the levels at which you should maintain your pool.

Shock FC is what you need to be at to clear your pool.

But with you CYA as high as it is.........you might have a need to go above these levels.

I really appreciate your replies! I'm sorry to have so many questions, but I'm still trying to make this make sense. I've been brainwashed by the pool store for way too long. I've never had any problems with algae or CYA until now, so I'm a little overwhelmed. And I've never had to deal with copper, so I'm really trying to put this all together.

So I'll use enough bleach to reach 25ppm for my weekly shock, and I'll keep it between 8 and 15 daily, right? This is as long as my CYA is sky high? (BTW, I tested it with some strips and it shows between 50 and 100 - can I believe the ALEX system?) This is the only pool store with a computerized testing system in my area.

With the chlorine levels this high, does this mean no swimming until it can be at 3 ppm?

Do I need to worry about the copper level? Since my pool place can't tell me what the reading is, I don't know what to do about it. I know I can order a test kit, but in the meantime, the copper is still there (I guess). Does it eventually go away?

Thanks again for all your help!

You need to hold your Shock value (25 ppm) until the pool is crystal clear. Adding chlorine everyday, 2, or 3 times a day to maintain 25 ppm. After you pool is able to maintain chlorine level ( dropping 1 or 2 ppm a day is ok) you can let it drift down to 8 - 15 ppm and maintain it at the level, adding chlorine everyday as necessary. IF you maintain the pool at these levels, there is no need for a weekly shock.

You need to get a good drop-based test kit, (strips do not cut it) whether the 5 way HTH kit from Walmart or the kit through this site. 5 minutes a day for testing and adding bleach is all you will need.

OK, thanks for that explanation. I understand; except for one detail. My pool is crystal clear and has been all summer. I saw green algae on the skimmer last week, but I brush it every day and have not seen anymore since. I'll do as you say and keep a constant check on it.

Can we swim in a pool with 8-15 ppm chlorine?

Thanks again!

With a CYA that high, yes, you can swim in it--it would be the same as swimming in a pool with lower chlorine and CYA, proportionally.

Janet

Thanks, Janet! I wish the pool stores in my area had as good an understanding of CYA as you guys do. I appreciate the help!

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Originally Posted by mccato

So I'll use enough bleach to reach 25ppm for my weekly shock, and I'll keep it between 8 and 15 daily, right? This is as long as my CYA is sky high? (BTW, I tested it with some strips and it shows between 50 and 100 - can I believe the ALEX system?) This is the only pool store with a computerized testing system in my area.

The most reliable way to get good test results is to get a good test kit and do it yourself. You will always test the same way - can't always be sure about the pool store employees

With the chlorine levels this high, does this mean no swimming until it can be at 3 ppm?

You can swim at the maintenance level of chlorine - for your CYA would be between 8ppm-15ppm. CYA binds and stabilizes chlorine and it also makes it less effective at high levels - which is why it's okay to swim.

Do I need to worry about the copper level? Well if you have shocked your pool and the whole thing hasn't turned into green kool-aid - I would say that copper is nothing to worry about

Thanks again for all your help!

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Go to the sister site http://www.poolsolutions.com and read all the articles - It will help you understand the process a little better.

BTW - all you really need is bleach, borax, baking soda - and MAYBE some polyquat - forget all that Bioguard stuff.