Green line on steps

[nickjohn35]

New pool owner here… after performing a weekly water test with the TF Pro kit and putting all the recommended chemicals in yesterday, my family and I went swimming today. After about an hour in the pool we noticed a green line on the steps at the water line. Apart from that, the water is crystal clear. I’m guessing I need more chlorine?

 

[proavia]

Welcome to TFP!

With a CYA of 40 (35 gets rounded up to 40), your minimum FC is 3 and target is 5-7.
Your FC got down to 1.0 a few days ago according to your PoolMath logs.

Dose FC for high end of target.
Do an Overnight Chlorine Loss Test to rule out algae.

How often do you test pH and FC?
What test kit are you using? EDIT: Disregard, I see you have the TF-Pro test kit
How do you chlorinate?

 

[nickjohn35]

Welcome to TFP!

With a CYA of 40 (35 gets rounded up to 40), your minimum FC is 3 and target is 5-7.
Your FC got down to 1.0 a few days ago according to your PoolMath logs.

Dose FC for high end of target.
Do an Overnight Chlorine Loss Test to rule out algae.

How often do you test pH and FC?
What test kit are you using? EDIT: Disregard, I see you have the TF-Pro test kit
How do you chlorinate?

With the test kit I’m trying to do a daily chlorine and ph test. I currently use liquid chlorine.

 

[Mdragger88]

Do just as @proavia instructed except you added 10 more ppm of stabilizer so 45ppm now which counts as 50ppm for chlorination purposes

Also, do you have a heater?
If not then you are in a “do not add” situation as far as calcium is concerned.
As far as ph & ta go…
Any ph in the 7’s is fine
When it gets to 8 lower it back down to the mid 7’s.
Any TA 50 or above is fine. No need for baking soda.
Adding acid then baking soda is like having your foot on the brake & the gas at the same time - it just puts you on a merry go round.

A couple more questions for you-
This happened after/during swimming?
Does it wipe/brush away?
Have you recently used/added anything besides the chems listed in your poolmath log?

 

[proavia]

With the test kit I’m trying to do a daily chlorine and ph test. I currently use liquid chlorine.

Are you using the chlorine/pH test block or using the FAS-DPD chlorine test for daily testing?
The chlorine test with the R-0600 only indicates if that is chlorine. It isn't overly accurate for a precise FC measurement.

 

[proavia]

Do just as @proavia instructed except you added 10 more ppm of stabilizer so 45ppm now which counts as 50ppm for chlorination purposes
View attachment 527038
Also, do you have a heater?
If not then you are in a “do not add” situation as far as calcium is concerned.
As far as ph & ta go…
Any ph in the 7’s is fine
When it gets to 8 lower it back down to the mid 7’s.
Any TA 50 or above is fine. No need for baking soda.
Adding acid then baking soda is like having your foot on the brake & the gas at the same time - it just puts you on a merry go round.

A couple more questions for you-
This happened after/during swimming?
Does it wipe/brush away?
Have you recently used/added anything besides the chems listed in your poolmath log?

I'd leave the CYA as is for now - or at least until after a successful OCLT.
With the OP being in Cincinnati OH and Fall on the horizon, a CYA of 40 this late in the season will probably be fine.

 

[Mdragger88]

I'd leave the CYA as is for now - or at least until after a successful OCLT.
With the OP being in Cincinnati OH and Fall on the horizon, a CYA of 40 this late in the season will probably be fine.

He already added it I was just telling him to account for his addition when chlorinating.

 

[BDY]

That line almost looks too uniform….could it be pollen that was on surface of water? Does it smear slimy like if you try and spread it on paper? Or is it more dust like?

 

[proavia]

He already added it I was just telling him to account for his addition when chlorinating.

Ah - I see that now. I was focusing on the last FC result.

 

[nickjohn35]

Do just as @proavia instructed except you added 10 more ppm of stabilizer so 45ppm now which counts as 50ppm for chlorination purposes
View attachment 527038
Also, do you have a heater?
If not then you are in a “do not add” situation as far as calcium is concerned.
As far as ph & ta go…
Any ph in the 7’s is fine
When it gets to 8 lower it back down to the mid 7’s.
Any TA 50 or above is fine. No need for baking soda.
Adding acid then baking soda is like having your foot on the brake & the gas at the same time - it just puts you on a merry go round.

A couple more questions for you-
This happened after/during swimming?
Does it wipe/brush away?
Have you recently used/added anything besides the chems listed in your poolmath log?

This happened during swimming. We would wipe it off with a magic eraser and it would could back in about 20 mins or so… No, no other chemicals.

 

[nickjohn35]

Are you using the chlorine/pH test block or using the FAS-DPD chlorine test for daily testing?
The chlorine test with the R-0600 only indicates if that is chlorine. It isn't overly accurate for a precise FC measurement.

Chlorine/PH test block for daily testing for now.

 

[nickjohn35]

That line almost looks too uniform….could it be pollen that was on surface of water? Does it smear slimy like if you try and spread it on paper? Or is it more dust like?

Just wiped it with my finger… it just smears…

 

[proavia]

Use the FAS-DPD test for daily FC testing.
Do the OCLT tonight.

Since the green deposit smears, chances are you have algae and will need to SLAM Process.

 

[Mdragger88]

Be sure you use the fas/dpd test not the yellow oto test for oclt & to get accurate fc & cc values.

 

[nickjohn35]

I believe I found the culprit. Did a FAS/DPD test and had no chlorine.

 

[BDY]

SLAM time then….
SLAM Process

hopefully it’s a quick one as the pool is still looking ok you said

 

[nickjohn35]

SLAM time then….
SLAM Process

hopefully it’s a quick one as the pool is still looking ok you said

Water still looks crystal clear. I wiped the green line off the steps after we all got out and the line never came back.

 

[BDY]

Hmmm….. did you do an overnight chlorine loss test? The thing with algae is your pool can be perfectly clear and still have an algae bloom starting

Otherwise it may not have been algae and may have been pollen or somethkng

 

[Newdude]

Check inside your skimmers. Do they have the same lines, or black ones ? Some new equipment like my cartridges or certain auto covers have an oily film that gets in the pool at first.

Or you went Gung Ho on the sunblock for the inaugural swim. .

But the oils really like the plastic and then grab anything floating by like pollen and yellow turns to black quickly.

Even if this doesn't apply, I reccomend 2 tennis balls in each skimmer at all times to absorb any oils/lotions. They work amazing.

 

[nickjohn35]

Hmmm….. did you do an overnight chlorine loss test? The thing with algae is your pool can be perfectly clear and still have an algae bloom starting

Otherwise it may not have been algae and may have been pollen or somethkng

Check inside your skimmers. Do they have the same lines, or black ones ? Some new equipment like my cartridges or certain auto covers have an oily film that gets in the pool at first.

Or you went Gung Ho on the sunblock for the inaugural swim. .

But the oils really like the plastic and then grab anything floating by like pollen and yellow turns to black quickly.

Even if this doesn't apply, I reccomend 2 tennis balls in each skimmer at all times to absorb any oils/lotions. They work amazing.

Unfortunately I did not have time to do a OCLT.

Yes, the skimmer have the same lines, maybe a bit darker green. This is all brand new equipment. Pool got finished about 4 weeks ago. I was thinking maybe it was from sunblock. After we got in, my wife said, "man, you can see the oil from our lotion on the water". It wasn't like a BP oil spill, but you could see it lol. Green line didn't start until we got into the pool. There was only 5 of us in the pool. Hmmm... I may have to purchase 2 tennis balls! Thanks!