Sentry caused near pool overflow and now clear green water

[engrav]

Pool looked fine yesterday and family swam.

We have a Sentry device to add water if the level is low.

Over night I guess it stuck in the open position as this AM the pool was about to overflow, so I backwashed it down to the usual level. Removed more than 10”.

Then the sun came out and I saw that the water had a green tint. It was very clear as I could see all the little imperfections on the bottom.

Nothing really to vac and brushing raised no wisps of anything.

Chems at that time were CYA 20-30, fc 3.5, cc 0.5 and pH 7.6.

Wife confirmed it was unusually green so I started the slam. Now only 3 hours into it.

But a question(s) please.

The coping is a cantilevered cement slab with slate on the top and on the water ward edge. Raw cement on the bottom. And am sure there are old mortar defects that permitted the water to pass up behind the water ward slates. Also probably water passed under the cement slab.

Then the added water was well water. Now we just discussed metals in another thread and the well water has no iron and manganese .057, barely above the contaminant level of 0.5. And the pool water check at that time had Not Detectable Cu, Fe and Mn suggesting the well is adding little of any of them.

Is there anything other than algae that might have come from the coping or the well that would make a clear green tint?

Thank you.

 

[Donldson]

I am not sure where it would have come from, but a clear green is much more likely metal than algae. Unless someone has better ideas I would suggest running an OCLT tonight. If you pass it but still have green tomorrow then it is almost certainly metal in the water.

 

[Bama Rambler]

A picture of the water would also help, but as Donldson said, it's most likely metals.

Did the water get darker (but still clear) green when you added the chlorine?

 

[engrav]

A picture of the water would also help, but as Donldson said, it's most likely metals.
Did the water get darker (but still clear) green when you added the chlorine?

thank you

Am away from the property but have fine pool checker person.
Overnight drop fc 1.5, 11 to 9.5. One drop more would have made 10 and decline ≤1 and not sure if his endpoint is the same as mine. Oh well. CC0.
He reports water remains clear and is now blue tint but not as blue as normal.
Added bleach to get fc to 12.

Have some pics but they are smartphone grabs and in extremely varying light not good.

I do believe water got darker when I added the bleach but...
At the same the sun was higher so the whole morning was like a light show.

Fires in E Washington are creating an interesting atmosphere. Sun comes up pink every morning. Then a few minutes later is yellow with a pink outer rim.

Anyway
will continue the slam and
I think it got darker when I added bleach (what does that indicate) and
I will get some DSL pics this afternoon with sun high.

Thank you

 

[Bama Rambler]

Iron in the water will usually turn the water a little brown when you add a lot of chlorine.

If it's turning blue I'd say you're on the right track by maintaining the SLAM.

 

[engrav]

Am back.

Color is basically back to normal (pic below). Some say I see a little yellow, some say I see a little green, some say it is now usual for this old pool, built in 42BC . But yesterday ALL said, nice pool you have with that lovely green tint and then "you should market that".

After 28 hours of slam. Seems kinda short. But I think I will keep on and do another overnight. Easy since I am here.

What was this episode? Dunno yet. Maybe never will. But will speculate if / when overnight drop ≤1.

What is the mess? Slate people putting loose slates down.

 

[engrav]

Yesterday after the 30' bwash to reduce pool level the bwash water was clear.

After measuring fc this evening for the overnight I did a quick bwash to see what the filter picked up yesterday and today.

See pic below. The emerging water was light reddish brown.

 

[Donldson]

Could be organic but I would say that points heavily towards iron. The good news of course is that it precipitated out and got caught in the filter.

From my HTC One via Tapatalk

 

[engrav]

thank you
interesting

fc drop of 1.5 last night was probably good enough to quit the short slam but will see what the overnight fc drop is tomorrow

if ≤1 can discuss how / where did the Fe come from

thanks again

 

[engrav]

good morning

no fc drop overnight so slam over
in fact, I think could have stopped yesterday given little corroborating evidence for algae
i.e. fc was never below recommended ranges

review
1) Sentry flooded the pool to near the top of the coping
2) pool was usual color
3) bwashed 30minutes and removed maybe 12" of water
4) pool then had green tint
5) tint got darker with slam
6) color returned to usual in about 24 hours with filter 24/7
7) overnight fc test passed after < 1 day of slam
7) bwash water was reddish brownish

Donaldson and Bama Rambler favor iron (both been round since 2009 so then 12 person years of pool experience)

since the well has ND (not detectable) Fe and the pool prior to this episode had ND Fe, where did the Fe come from?

how about this for an explanation?
1) water was at the top of the coping
2) pool is old so the joint between cantilevered coping and the beam is no longer sealed if it ever was
3) water passed in around under over the coping and the beam
4) water found exposed old rusty rebar and construction debris and picked up some rust particles
5) before wayward water had a chance to drain away into the dirt, I bwashed and as water level dropped in the pool, some of the water in around under over the coping and beam drained back into the pool bringing the rust

sounds logical to me, but then

why would rust particles turn the water green?

well, in the spectral colors I guess green lies between blue and red so maybe with the smokey atmosphere, funky sunlight, blue/green water and a little reddish rust >> green tinted pool water

I guess sounds logical

 

[engrav]

Hi

Bwash today was clear so the stuff was removed in say 30hrs of filtration.

Does this suggest anything like There was not much? Particles were kinda large so glass got 'em easily?

 

[Bama Rambler]

It suggests that raising the FC quickly and as high as you did oxidized the iron and allowed it to be filtered out, and that's a very good thing.

 

[engrav]

A funny, I think anyway

During all of this I captured some water samples so took 'em this AM for analysis (Fe, etc)

Mind you this is S Whidbey Island, totally rural, no Starbucks.
There is a well pump company next to the analysis drop-off. While I was filling forms old geezer (older than me) came out. Looked like he has worked outdoors for 142 years installing well pumps. Said "so you getting analysis?"
I said yes and explained.
He said "Why waste your money? It's obvious, when the water ran back into the pool, it brought sh.t and slime."

So am so sorry Donaldson and Bama Rambler, was not Fe, was actually sh.t and slime.

=========
Why get Fe analysis? Well, pool had not detectable (ND) iron before so if now > ND would be rather confirmatory.

Also see pic below. Even now 48 hrs later there is a little something in the bwash water.