Hint of Green

[jonkmj]

Hello all: New to this forum and have to say I have found the information here to be awesome. I have done lots of reading in the last few weeks, and am now convinced that the BBB method is the way for me. Here is my issue:

Had a problem with algae upon opening up my pool this year. Had lots of leaves and "stuff" in bottom because I didn't get it covered in time last fall. After using the HTH "pool shock" packets and testing with the cheap OTO test kit from Wal-Mart....the algae took over!! Anyway, after finding this site I ordered the TF-100 test kit and it arrived within a few days. Once I had a reliable test kit and using the pool calculator I took the pool up to shock level with 12.5% liquid chlorine and have maintained the FC level at 22 mg/l or greater for the past two weeks. I have skimmed out all the leaves and debris now and have brushed the entire pool several times and vaccumed several times as well. Been running the sand-filter non-stop and the water has cleared and you can easily see the bottom of the pool; but the water still has a slight green hue to it. My wife would like to know "when is the pool not going to be green?".....and goodness knows I want to keep her happy! Can anyone answer her question??? I would like to let the chlorine levels start dropping....but I'm slightly afraid that with the "hint of green" the algae may just be subdued, lurking and waiting to explode.

Here are my latest #'s
FC = 24 mg/l
CC = 0.5 or zero
CYA = 50
Ph = 7.2
TA = 180 mg/l

Any insight inot my situation? Thanks in advance.

Mike

 

[JasonLion]

Welcome to TFP!

To know when you have killed all the algae, you can do an overnight FC loss test.

If the water is a clear transparent green, and the overnight test shows a drop of 1.0 or less, you should try adding sequestrant to the pool. If the overnight drop is more than 1.0, you need to stay at shock level for longer.

 

[jonkmj]

OK. Will try the overnight FC test....but I'm reasonably sure the FC will not drop much. I will update tomorrow. I would say that the water is clear and transparent with green color. I was doing some more reading here and I found some stuff that indicates this could be from copper. I assume that is why you recommeded the sequestering agent. So my next question would be: Assuming it is copper......will the sequestering agent bind the metal and allow the filter to take it out or does it just keep it in solution? Thanks again for all the help and information. This site is awesome!!!!!

 

[TizMe]

You need to continue to shock the pool until,

1) You have a FC loss of less than 1ppm over night
2) Your CC is less than .05
3) Your water is crystal clear

I suggest doing a FC loss test. To do that you add enough chlorine to your pool after sunset to bring it to shock level for your CYA level after the sun sets then in the morning before the sun gets on the pool check it and see if your loss overnight was less than 1ppm.

The reason you should do the FC test at night is because chlorine loss is caused by sunshine as well, so doing it at night rules that out so any FC loss more than 1 ppm suggests algae.

 

[TizMe]

I guess we were all posting at once :lol:

 

[frustratedpoolmom]

OK. Will try the overnight FC test....but I'm reasonably sure the FC will not drop much. I will update tomorrow. I would say that the water is clear and transparent with green color. I was doing some more reading here and I found some stuff that indicates this could be from copper. I assume that is why you recommeded the sequestering agent. So my next question would be: Assuming it is copper......will the sequestering agent bind the metal and allow the filter to take it out or does it just keep it in solution? Thanks again for all the help and information. This site is awesome!!!!!

Unfortunately if the copper levels are high they remain "in solution" by using maintenance doses of sequesterant. Otherwise they could stain pool surfaces. It turns hair green...ugh. Eventually the levels will drop, thru water replacement and backwashing, etc. (I used to have copper too...now copper free!)

 

[JasonLion]

Green water can also be iron if the pool surface is blue. Iron turns the water yellow, plus a blue background, gives green.

 

[PaulR]

I found some water-quality strips at Home Depot a while back that included copper and iron tests. Might be worth a shot. If it turns out to be iron I heard about a scheme to get rid of it, recently.
--paulr

 

[jonkmj]

OK....great. Thanks all for the info. I will check out Home Depot for those test strips. Couldn't hurt. I tried the overnight FC test last night, but it has basically rained all night and all day today (about 1" or rain...pool skimmer over-flowing now), so my results were skewed. Kids have been swimming (even in the rain!) last couple of days....and no one has green hair. Today the water seems to have a bit less of the green tint. Some other thoughts: I may be jumping the gun with the copper theory because I'm not sure where copper would have come from. I did use the 3" chlorine tablets for the first two years we had the pool, but have only used the "dual action" type and not the Tri-chlor...which if i understand correctly is the one with the copper based algaecide. I also have used the HTH Algae Guard bought from Wal-Mart, but best I can tell from reading the label on the jug this does not appear to be a copper sulfate based algaecide. I don't currently have a pool heater that could have leached copper from the heating coils due to low pH or something.... So, I just can't see where the copper would have come from. Anyway here were tonights test results.
FC = 7.0
CC = 0.5
pH = 7.2
TA = 120
CYA = 50
Thanks again for all the insight provided thus far....and for that which has yet to come.

Mike

 

[JasonLion]

Try adding a metal sequestrant. ProTeam's Metal Magic and Jack's Magic the Pink Stuff (regular), the Blue Stuff (fresh plaster), and the Purple Stuff (SWG) are some of the top sequestrants. You can also find many other brands with similar products, some of which are noticeably less expensive. Sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives are the most effective.

 

[anonapersona]

I'm just wondering.... all those leaves and sticks over the winter.... might they have tinted the water a bit brown? As that brown thins out to yellow with rain, add blue and it would look greenish. Or will chlorine just bleach that brown out to nothing?

I'm too new to this to know, so I'm just asking to try to help the OP.

 

[duraleigh]

Or will chlorine just bleach that brown out to nothing?

Most likely. It's not uncommon here in NC to get Tannic acid stains from leaves and gunk if you have neglected the pool for a while (Now, how would I know that? ) It still an organic stain and high levels of chlorine will get rid of it.

 

[PaulR]

I may be jumping the gun with the copper theory because I'm not sure where copper would have come from. I did use the 3" chlorine tablets for the first two years we had the pool, but have only used the "dual action" type and not the Tri-chlor...which if i understand correctly is the one with the copper based algaecide.

Straight trichlor does not have copper. I googled "msds hth dual action chlorine" and it is trichlor, copper sulfate pentahydrate, and aluminum sulfate. So, that could be your copper source.
--paulr

 

[jonkmj]

Hello All. Sorry I haven't posted in a couple of days. We were away this weekend. Took chlorine up to 12 or so before leaving. Left pump and filter running while away (and a gracious neighbor babysitting pool). The pool still had the "hint of green" when we left. Didn't add any metal sequestrant. Had another 1.5" of rain while we were gone. Returned yesterday to find the FC down to 6mg/l.....but the "hint of green" is gone!! The pool is getting more sparkling blue by the day!!! It would seem that all I needed was just a little more "POP". I will try to post some pics soon. Thanks again to everyone who offered advice and guidance.

Chalk this one up to another TFP sucess story. You guys...and gals....are awesome!!!

Mike

 

[Butterfly]

That's great! Congratulations

Just want to follow-up with the "you are done shocking when" info, again:

(Chem Geek's criteria)
1. You lose 1 ppm of FC or less overnight and,
2. Your CC is 0.5 or less and,
3. Your water is sparkly

I am repeating this info just to make sure you that you have met all three criteria :-D