Algae or ..? Can't tell what's going on.

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#1
Hi, everyone.

Never had to deal with algae before, but suddenly (as of about 5 days ago) my water has a greenish tint to it. The water appears to be fairly clear, and at a depth of up to about 1ft - 1.5ft it appears clear, but deeper than that there's an obvious green tint.

This started during a period where the FC dropped to 1 or less for a day or two, so I feel pretty confident the issue could be algae, but there is no "particulate" or "algae slime" or "cloudiness" that I have been able to observe. Just an unsightly green tint. I can still see straight through to the bottom of the pool with pretty good clarity, it's just greenish.

My pool walls and floor appear ok, no signs of visible algae, but I've swept them anyway. I also cleaned my cartridge filters last night before pouring in an entire bottle of liquid bleach 6%. The filters were dirty and had bits of live oak twizzles in them, but the filters were not so dirty that it raised my pressure gauge at all. I've had the pool pump running constantly since yesterday evening.

I do know my CYA levels are low- I've had trouble bringing that up, though I've put in an entire bottle of powdered CYA though the skimmer with the sock method starting last fall.

I've begun raising my FCs and for the last few days they've been at normal levels, and yesterday I introduced some more liquid bleach for a current FC of 9.

I want to hear your opinions first, but as of now I'm planning to raise FC to 12.

So, do you think it's algae? Is it something else? Could it be algae although my max CC has been .5 and currently CC is 0?

My wife wants me to add that during the time this started, the large live oak that hangs over part of our pool was dropping green pollen everywhere. So perhaps it's just that?

Here are my current readings:

FC 9
CC 0
PH 7.5
TA 60
CYA 20

Thanks for your thoughts!
 

domct203

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Jun 3, 2015
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#2
If the water is perfectly clear, but tinted green this could be metals in the water, most likely iron.

Do you fill from a well? Have you been using algaecides or granular 'shock' that contains copper?

If you want to rule-out or confirm algae, perform an OCLT.


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TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#4
I took two tests last night, one was at 8.5ppm FC and an hour later I had a reading at 10ppm FC. This morning my avg of 3 readings is 8ppm. That's a loss of about 1ppm, with my CCs jumping to .5 from 0 on my last sample yesterday.

I also looked at the water, and found it is a bit cloudy afterall. I mean, you can still straight through to the bottom and make everything out and the water looks clear, but at night, with the pool light on, you could see the cloudiness around the pool light.

Any ideas? I'm trying to decide between shocking or adding clarifier.
 

duraleigh

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#5
I took two tests last night, one was at 8.5ppm FC and an hour later I had a reading at 10ppm FC. This morning my avg of 3 readings is 8ppm. That's a loss of about 1ppm, with my CCs jumping to .5 from 0 on my last sample yesterday.

I also looked at the water, and found it is a bit cloudy afterall. I mean, you can still straight through to the bottom and make everything out and the water looks clear, but at night, with the pool light on, you could see the cloudiness around the pool light.

Any ideas? I'm trying to decide between shocking or adding clarifier.
FC cannot go up unless you add FC. You have a testing error.

The endpoint of the test is when the last drop of R-0870 makes no FURTHER color change, you subtract that drop and the result is your FC. Since the OCLT only allows a 1 ppm drop overnight, your starting test last night was invalid.

After all that, your results certainly point to excessive chlorine loss and I would SLAM the pool. If by "shocking" you mean a one time dose of Chlorine, there is a good chance your algae will return.

Please read the SLAM article in pool school to get your pool back to crystal clear.

Clarifier can make matters worse and we virtually never suggest it's use.
 

YippeeSkippy

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Jan 17, 2012
9,079
Evans, Georgia
#7
Did you have the SWG on during the OCLT?

If your pool isn't sparkling, something is in there that needs to get out!

Take that CYA up to 30ppm (easier to read on the test) and SLAM with it at 30ppm. Turn the SWG off during the SLAM so you can monitor loss easier.

After the SLAM is over, add the extra CYA needed for the SWG per this chart--> [FC/CYA][/FC/CYA]

Okay?

Yip :flower:
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#8
Well, here we go!

Turns out my CYA is actually 60.

I added two bottles of bleach late this afternoon and let it mix for a while before taking a test this evening (after also turning off the SWG for an hour.)

Currently, FC is 26. Water is still "clear" but not "crystal" clear. I remember when I first filled the pool, when the water was calm, there was a moment when I doubted there was even water in it! Right now you can see some cloudiness in it which is obvious with the pool light on, but for most people it would seem "clear".

We'll see how things look in the morning with the OCLT.
 

Patrick_B

TFP Expert
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Jun 7, 2011
14,999
Midland TX
#9
Looking forward to your answer. Crystal clear in the Daylight is what matters. Every pool shows something in the lights at night. Far Less with DE filters, and Carts, but there is always something in the water.
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#10
Wow, wasn't expecting this. My morning OCLT FC test shows I'm at 16 FC, I couldn't believe it so I tested again and got 17.5 FC. I'm dismayed at the variance, but figure it must be the lack of precision on how powder goes into the sample vs the exact size of the drops each time.

Either way, my reading last night was 26 so there is something in there!! I really wasn't expecting there to be anything! I was doing this on the "just in case" ...wow!

Time to go to pool math to figure out how much to add ...

Thanks for your help!
 

domct203

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#11
Be sure to hold the reagent bottle as straight and vertical as possible. Don't rush the drops, let them form and drop at the rate of about one drop per second. This will help keep your drop size consistent.

I also use a speed stir, and my FC tests repeat within 0.5ppm (one drop with the 10ml sample).


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duraleigh

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#12
Dom speaks the gospel. The test is very precise but has to be performed pretty carefully. Be sure you get a definitive endpoint, too.
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#13
Thanks for the tips on more precise measurement! Wasn't aware of the proper way to hold the bottle.

Current FC is 23.5 so time to bump it up just a bit, then start vacuuming. Oh yeah, I just walked outside to take a test and saw a duck (green head) flying out of the pool. They seem to like to hang out in the mornings.

Water looks clear (it's always looked pretty clear to me) ..no signs of any algae residue ...the green-tint to the water may be gone, too ..will be able to tell more when the sun is higher in the sky.

I do have sand that collects in the pool. I live in a sandy area so that's not uncommon, but going to try to vacuum it out this morning.

Oh- I do have a stirrer ..I love that thing!
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#14
Vacuum was a big fail. The first time I've ever done it and the vacuum hose did not fit snug with the suction port underneath the skimmer basket. The vacuum hose diameter is too small. So, I guess I'll just keep brushing and move the dirt around.

I also decided to turn the SWG on 15% ..figuring that it will help keep the FC up, and a few ppms above 24 won't hurt. Can turn it off over night.
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#15
Well, the green tint is still there. I'm starting to doubt myself and wonder if that's just not the color (Stonescapes Topical Blue) or reflections from the live-oak or bushes, but my wife assures me it is not ..and then there's that 9-10ppm OCLT loss.





 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#17
Current reading is FC 24. The water is clearer than it was yesterday evening. Got the wife to confirm!


Going to add a bit more bleach to raise the level in case there is still overnight loss. Don't want to drop below SLAM level over night.
 

TxCoolGuy

Active member
Sep 1, 2016
34
North Richland Hills, TX
#20
I've been checking every couple of hours. The severe thunderstorm that hit early this morning has really thrown me off. The OCLT FC reading is now 20.5ppm where last night's was 24ppm ..but with what might be 3/4 an inch of rainwater introduced, I believe that would invalidate the test.