Numbers are ok, but algae lingers...sort of...Help

nabril15

Bronze Supporter
May 22, 2011
399
Miami, FL
Good morning all
For 2 or 3 years, I've had my pool understood and under control thanks to TFP and its teachings. I thought that I knew my pool, and that we had a good relationship.

About 2 months ago, some green stains appeared on my walls and on some parts of the floor; I opened a different thread for it and got help there. Despite 2 SLAMS, the stains remained, so I went in with a kitchen sponge, yes, and scrubbed everything. Cool.
My FC remains higher at 12, than it should be, and the green stains have returned. Despite brushing every other day, the brush goes right over them as if nothing. The brush will remove "normal" algae, but not these stains. My FC has been slowly coming down from the last SLAM 2 weeks ago, and I stress that the water has been and remains crystal clear. I haven't been able to measure my ph since before the SLAM, so I've been letting the FC drop to 10. In doing so, I brush a small amount of algae of the floor.
**Note. I started the slam without bringing the ph down to 7.2 since I wanted to kill those stains right away. So I just took FC to slam level, and poured 10 or 12 ounces of MA before just as a precaution. My purpose for the slam is to get rid of those wall/floor stains; the rest of the pool looked and looks perfectly fine.

Saturday's numbers: FC 14, CYA 60, Temp 80, TA 60, CH 225.
Despite our hot temperatures down here, my FC is creeping down slowly; it was 12 this morning.
So. I'm torn. My FC has been coming down very slowly, and of course algae is getting brushed.

I feel like I've lost control of my pool, despite the daily reminder of crystal clear water and numbers that appear normal (except ph that I haven't measured since the last SLAM).
My thought: KEEP BRUSHING and let the FC go down to 10 so that I can get an accurate ph reading and have a complete set of numbers. And then maintain the normal weekly maintenance. Does that sound smart? However, the stains remain, so I will have to SLAM yet again...
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,624
SW Indiana
Any chance you have copper in the pool? Cheap algaecides, alternative “sanitizers” and corroded heaters are common sources.
 

nabril15

Bronze Supporter
May 22, 2011
399
Miami, FL
Thanks John
You had suggested copper in the other thread..
I haven't used algaecides or sanitizers, and I don't have a heater. I can say that one of my my well water sprinkler heads does put a small amount of well water in the pool, but I would assume that it's not significant.
Wait. That head is near the deep end, and that is where most of the staining is happening. Hmmmm.

However. I scrubbed the walls 2 or 3 weeks ago BUT I haven't used the sprinklers in that time because of rains. Could it be that the copper remains in the water???
Dang.
 

nabril15

Bronze Supporter
May 22, 2011
399
Miami, FL
GM. This morning, FC is at 12, and the water is looking slightly murky and I brushed a lot more algae.
Do I have to just sit patiently until FC = 10 so that I can measure the ph, then lower it to 7.2, and then SLAM? Even if I keep brushing more and more algae?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,827
Northern NJ
It would be helpful to log all your tests results in PoolMath.

What is your CYA?

Lowering the pH before raising the FC makes the chlorine more effective. You slowdown and handicap the SLAM Process if you don’t adjust the pH.
 

nabril15

Bronze Supporter
May 22, 2011
399
Miami, FL
It would be helpful to log all your tests results in PoolMath.
What is your CYA?
Lowering the pH before raising the FC makes the chlorine more effective. You slowdown and handicap the SLAM Process if you don’t adjust the pH.
THanks ajw..Yes, I know that I have to lower the ph before the slam, but it's "weird" for me to now sit and let the pool get worse so that FC drops, so that I can then test ph, and then begin the SLAM.
My CYA is 60. The OP has the latest readings.