Black algae

[ProspectHill]

Update.
I contacted the pool company. not a retail pool supply store- the people who built the pool and maintain my equipment.
They confirmed most of what I found here with one difference.
they don’t use liquid chlorine or household bleach.
anyof those supplies are too old by the time they get to our island.
everything comes in by boat and lingers long in warehouses and docks.
instead they suggest putting on a glove and rubbing a puck on the spots.
also hang a sock with the puck directly over the spots. ( Similar to advice I found here.)
best to do this while the pump is off so the water doesn’t just circulate it.

also, brush brush brush. Often, every day.

they concur that the SWG and floating puck are ok, but are not effective on the black algae. Only direct contact will do the job.

they tell me I’m in for a long tedious process.
and once you have black algae you keep it. Even though the visible appearance my fade, the roots are still there.
so you stay vigilant in making sure the pool is not generating any food for algae. It’s biding it’s time, waiting for a chance to bloom again.

 

[Katodude]

Not completely true. By pouring or spraying some liquid chlorine directly on the spots (after you have scraped them). You can pretty much eradicate the black algae.

However, be prepared to join #teamrunshot @Newdude will explain that to you.

For a few weeks after you have killed all the black algae spots, run your FC at 20% of your CYA.

Then for the rest of the life of your pool you should run your FC at 10% or higher than your CYA. Do that and you will never get Black Algae.

 

[Newdude]

+1. Your pool is telling you that typical amounts of daily chlorine aren't cutting it. The added bonus of adjusting your target higher, is that regular old algae will never be a thought again. You'll never get caught off guard again by a big storm or a particularly high UV loss day.

More (chlorine) is Less (headaches).

 

[ProspectHill]

Not completely true. By pouring or spraying some liquid chlorine directly on the spots (after you have scraped them). You can pretty much eradicate the black algae.

However, be prepared to join #teamrunshot @Newdude will explain that to you.

For a few weeks after you have killed all the black algae spots, run your FC at 20% of your CYA.

Then for the rest of the life of your pool you should run your FC at 10% or higher than your CYA. Do that and you will never get Black Algae.

Got it!

 

[ProspectHill]

i don’t see a trace of the algae.
after donning gloves and snorkel, with a wire ‘toothbrush’ in one hand and a puck in the other, I brushed and rubbed every spot.
I was so thorough I found myself scrubbing a couple stubborn spots only to realize, after pulling back, I was attacking the aggregate.
Then I placed the puck flat onto the bottom and rubbed it around the general areas that had spots.
I hung a ’sock puck’ on a pole and left it hovering just a half inch over one area overnight and moved it every few hours all day.
then I repeated the whole process just now. Even though I saw no algae spots.
the FC is at 8. Last reading had CYA at 53-55. Ran out of regent for that.
pill get some bleach anyway…..just because…can’t hurt, right?

thank you everyone for your dedication to The Pool.

Marcia

 

[JamesW]

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[proavia]

Round CYA up to 60.
Any time CYA reading falls between the lines on the vial, round up to the next larger number.

Dose FC according to your CYA of 60.
Shoot for the high end of target range.
FC/CYA Levels

 

[ProspectHill]

I see. FC at 8 is mid target so I can go higher.
thx

 

[ProspectHill]

While up close to the pool surface for so long I noticed what I believe may be a different beast. Three stains. They are far apart from each other. A black dot surrounded by a blue bruise. No amount of scrubbing and puck rubbing has an effect. I have a picture attached . The color doesn’t represent well. The diamond bright plaster has a warm grey aggregate, but reads as white.

 

[ProspectHill]

The stain is about an inch around.

if these three spots are isolated blackheads from the same algae, they don’t respond the same.
I don’t know if I should have started a new thread or kept this going here.

 

[proavia]

I see. FC at 8 is mid target so I can go higher.
thx

Be aware that the pH test is not valid with FC abofe 10 (unless you are using a pH meter).
If running FC above 10, let it drop down and then test pH.

 

[ProspectHill]

Good to know! Thank you.

 

[ProspectHill]

Hello.

I finally got the Taylor FAS DPD Chlorine test kit.

Here's everything I know now about my chlorine.
Taylor test with regents 01, 02, 03 from K-2005 kit:
FC 10. it dropped down to 7.5 in about 15 seconds and continued to fade.
So I didn't perform the TC CC tests.

Test from pool store:
FC 10.59. TC: 12. CC 1.41

Test from new Taylor FAS DPD:
(1 drop = 0.5ppm, arbitrary choice, don't know if 1 drop = 0.2ppm would be better).
FC 11. CC 0 ( no pink after 5 drops ...03 regent )

I had boosted the chlorine level when hurricane Phillipe passed close by, dropped a lot of rain, and knocked out power for 36 hours.
So I floated a couple pucks and had the SWG already set for 70% at a run time of 10 hours.
I just now turned it down to 50% and the pucks are almost gone.

CYA - 60
PH - 7.6
ALC - 80 ( will bring it to 90 )
CAL HARD - 410 ( a little high?)

How am I doing?

 

[PoolStored]

Doing GREAT!!!

Leave your TA alone. 60-80 is perfect.
CH is fine. Leave it alone.

Follow this link-->FC/CYA Levels

and keep your FC in range for your CYA. High end of the range is just perfect.

Ignore all other testing and trust your test kit.

Congrats!!!

 

[ProspectHill]

THANK YOU.

I'll bring my Chlorine down to around 8 or 9 and keep it there.