What I have done!

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Don't bother testing at the pool store for CYA. Their testing is suspect across the board and they get CYA the most wrong of the bunch with their fancy electronic testing... Trust your results and go with 70 ppm CYA. Keep in mind that you can repeatedly dump the test mixture back into the dispenser, shake briefly and then retest into the viewing tube to get a better feel for the test. Remember, full sun at your back during the test.

No need to lower FC, it's not going to harm your pool at that level with your CYA at 70. Just let it come down naturally with sunlight exposure.

They could do the test for metals as that will be a free way to give you a ballpark of whether or not you have a metals problem.
 
First, SUPER THANK YOU to everyone how gave my some feedback. It is so appreciated.

Yesterday, my husband was really worried about the FC level. He made a fine powder from 250g of Vitamin C (100% ascorbic acid with absolutely nothing else) and drop that powder slowly in the skimmer. We did nothing else to the pool. The pump is still on max speed and running 24/7.

This morning the green color is almost all gone, the water is clear and the water temp is at 46F. I did the FC test in the following manner: 5ml of pool water with 1 heaping scoop of DPD powder = turned bright pink, then added 15 drops of R-0871 and it became a very light pink = FC??? I do not know which way to multiply. I continued on adding a few drops but the light pink does not budge. Should it turn completely clear? Why is it staying slightly pink? Adding 5 drops of R-0003 did nothing to the color so CC=0. - As I wrote this post (15-20 minutes), the solution is getting brighter, more pink. I did not through it out yet, it is still on the counter. Is this normal? Could we have an issue with one of the chemicals involved in the testing?

I have checked our well analysis of the last 3 years, and we never had an issue with high levels of copper in our well. We are in for another cold cloudy day. Every day the weather forecast pushed back the warmth and sun.

What do we do now?

1) Slamming: are we done? do I go back to the check list for the slamming process?

2) Copper: I am thinking of paying for a lab analysis of the pool water at the same lab we get our well water tested every year. I have read the suggested threads on copper. The only solution is to change the pool water. Other than potential stains from the copper any danger to the pool equipment? Can it damage our new heat pump? It has titanium coils. I am wondering if we can live with this for this summer and lower the level before the winter, empty further next spring and fill with brand new water. If we change the water this year, I have to wait until the FC level is back to zero, we empty directly in a forest.
 
Glad to hear your husband's use of vitamin c helped. That's a clear indication of metal for sure. As for the chorine, here are the different ways you can measure - 10 ml probably being the most common:
5ml sample, multiply drop count by 1 (used to save on reagent; not as precise)
10ml sample, multiply drop count by 0.5 (standard method)
25ml sample, multiply drop count by 0.2 (used for extreme precision)
Click to expand...
Yes, if you leave the solution just sitting the pink will return. :) As for the copper that we suspect, staining is about the only real concern. It should not effect your titanium coils. You might be able to avoid the green reaction by maintaining a lower FC level, but you have to be careful about being in-line with your current CYA as noted on the Chlorine/CYA Chart. You certainly don't want algae.

Speaking of which .... do you need to SLAM? Well, at this point I would suggest doing an overnight test per the Pool School - Perform the Overnight FC Loss Test (OCLT) page. If you pass the OCLT, then there's no need to SLAM and you can simply focus on the metals.
 
Texas Splash said:
Speaking of which .... do you need to SLAM? Well, at this point I would suggest doing an overnight test per the Pool School - Perform the Overnight FC Loss Test (OCLT) page. If you pass the OCLT, then there's no need to SLAM and you can simply focus on the metals.
Click to expand...

So here are my numbers:

Yesterday morning at 6:00 FC 15 (15 drops in 5ml sample) and CC 0 Water temp 46F
Yesterday night at 20:00 FC 11 (22 drops in 10ml sample) and CC 0 Water temp 50F
This morning at 5:30 FC 8.5 (17 drops in 10 ml sample) and CC 0 Water temp 48F

The water is clear, no green tint at all. Nothing in the skimmer. Some debris on the bottom but nothing a good vacuum would not solve. The pump is still on max, 24/7. Looking forward to reducing it to min.

Do I have to go back up to slam level? I was aiming at that when I got the green scare. We opened the pool just last Saturday.
 
I'll be honest Lousie, you lost quite a bit of FC overnight - much more than the overnight (OCLT) test permits of 1ppm. :( What was you last CYA - 70 right? That meant a SLAM FC of 28 I believe? It seemed like somewhere between the 28 and your drop to 15-ish (along with the vitamin C) your water cleared. So apparently your water has a threshold level where the copper and chlorine react with each other. We know that to rid a pool of algae/organics you have to SLAM. So anyone with metal in the water (iron or copper) must kill the algae first, then deal with metal. So I would be inclined to recommend the following:
- Test CYA again first. If it's still 70, we know that means an FC of 28 which might make your water change green again - temporarily at least.
- So you have a couple options: a) Raise FC to 28 and deal with (potentially) the green after the SLAM; b) Consider a partial water replacement to lower CYA to 60, 50, or even 40. That would require a much less FC SLAM level that may keep the water from reacting like it did before. With that water exchange, if you could refill with even just a little copper-free water, you'd not only lower CYA but also the metal content... WIN-WIN!
- Once you confirm or adjust the CYA, then slowly raise the FC to the applicable SLAM level and perform the SLAM to kill any algae from the winter.

After the SLAM you should be able to let the FC go back down to its target level and get your clear water back again. How does that sound?
 
It makes absolute sense! Back to the slamming process... I have added enough liquid chlorine to go from FC8.5 to FC28 based on the PoolMath with CYA at 70. I have also turned off the UV lamp to make sure it does not interfere with the FC level. Nobody is home today so I will check on the pool tonight, correct the FC level if needed, check the FC again before going to bed and again tomorrow morning for the OCLT. I will then post my numbers.

I promise I will not panic if the green Fairy appears again in my pool while my FC is high!!

Thanks a bunch for the help and guidance.
 
Good morning,

So here I am with the slamming process:

Yesterday at 19:00 FC21 (5ml sample + 21 drops) and CC0 water temp 50F -> I have added 2.4 liters of 10.3% liquid Chlorine to get back to FC28
Yesterday at 21:00 FC31 (5ml sample + 31 drops) and CC0 water temp 50F
This morning at 5:50 FC31 (5ml sample + 31 drops) and CC0 water temp 48F

The green fairy is back! The water is crystal clear but green since I got back yesterday night. So we know now that at FC21 or more our water reacts and turns green.

My understanding is that the pool passed the OCLT. Now I let the FC go down to its maintenance level?
 
Congratulations on the OCLT passing. Yes, let the FC drop so you can turn your green to clear again. :) It's good to know that "magic number" for the next time you want to host a St. Patrick's Day party. :) Although by the end of this year, with water exchange throughout the season, you may replace some of that metal water and not have the same issue. I guess time will tell. Good luck!
 

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Has anybody here talked to you about the UV unit? There are a number of folks here that have done research and the general consensus is that they really have no benefit in outdoor pools. There are claims that they allow lower amounts of chemicals to be used, but this is not found to be true.

There are folks who are much more versed in this and I suggest you do some searching around the site and see what you might find.

Here is a clip that I found, "UV light can kill pathogens and some of the units also produce some ozone but this only occurs in the contact chamber and there is no residual effect in the pool. Once again, more useful in a spa than a pool. UV might be of some value in an indoor pool in conjunction with chlorine to help destroy persistent chloramines."

There are many others along that line.
 
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