Brown spots on floor of sun deck

Dr.Ron

Member
Jul 9, 2016
15
Manalapan, NJ
Hello. I have (newly this year) brown spots on the floor of my sun deck (mainly). They can be somewhat scrubbed off with a sharp object but only after a decent amount of elbow grease. The pool brush does little to nothing to remove them. The top layer of these colony looking things are dark brown. When rubbed with previously mentioned sharp object (like a screw driver blade or such) the brown puffs off into the water and there are green blotches underneath that. With decent effort they can be somewhat scratched off but a slight green stain remains behind. There are 100's of them on the sun deck. There are only few around the rest of the pool. There are also small black patches along some of the edges of the pool, where the floor meets the walls.
The water is the clearest it's ever been and the chemistry is great. Chlorine is 2.5ppm or so. The only thing is the calcium hardness may be a little high. The gunite pool is 43,000 gallons. Salt cell system.
These have never been in the pool before.
Any idea how to get rid of them/kill them and prevent their return? Any easy way to scrub/remove them from the surfaces of the pool?

Thanks in advance!

Ron
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
13,758
Evans, Georgia
Ouch! Whatever you do, please don't follow the advice on that website!! Putting copper into your pool is a recipe for a whole 'nuther set of problems.


Maddie
 

Dr.Ron

Member
Jul 9, 2016
15
Manalapan, NJ
I just googled brown algae & that pic came up so I provided the link.
I was not using that website for info. lol
And mine is not that bad, but the spots look like those but smaller.
 

Dr.Ron

Member
Jul 9, 2016
15
Manalapan, NJ
What are your test results?? That FC of 2.5 sounds dreadfully low to me.
FC-The chlorine was 2.5-3 ppm. Isn't the normal range 1.5-3?
CC-Not sure what this is.
pH-8.4! Added acid earlier today though. Don't know how alkalinity went up like that.
TA-Total alkalinity? not sure
CH-250
CYA-45
Salt-if appropriate-3000

Maddie
Scrape one off unto a piece of white paper or an index card. Is the schmear green??
We scraped it off the pool floor and there was a green smear left behind. I can try to retrieve one from the pool and do it on a piece of white paper.

Thanks for the responses!
 

Dr.Ron

Member
Jul 9, 2016
15
Manalapan, NJ
That's what I deduced. We have the chlorine at about 15 for 3 days, then 10 for a day. Down to 6 today.
We brushed and scraped as much as we could. Even use a putty knife and a flat head screw driver & still couldn't get it all off. It is WAY WAY better now. It wasn't horrible, but it just made the pool look dirty.
I also opened the filter and cleaned all of the grids and put new DE.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
13,758
Evans, Georgia
How did you decide on that "We have the chlorine at about 15 for 3 days, then 10 for a day." ??

Are you flying blind in regard to testing and following the SLAM process?

Maddie :flower:
 

Dr.Ron

Member
Jul 9, 2016
15
Manalapan, NJ
I guess you might say that. At least with 1 eye closed. :(
What should we have put it to?
Next year I plan to empty the pool and have the surface power washed anyway (was going to have it done this year but we didn't) so I didn't really follow the book 100%. But my water is crystal clear!