Cant beat these algae colonies

[ranger_ric]

I have been trying to slam my pool since the 28th of MAY. I still have blobs of brownish/slightly green algae stuck to the bottom of my vinyl pool. I have bribed 3 of my grown children with steaks to get in the pool at SLAM level with green kitchen scrubbies on their feet to scrub this stuff away. I have for the last two days been maintaining the SLAM at 2-3ppm FC above recommended SLAM level. I have also been sweeping/"scrubbing" it with the pool brush at least 6 times / day. I even got in it today with scrubbies on my feet and went after the algae. Some of it would scrub up but most of it was very stubborn. I have been at this now for almost 2 weeks will this stuff ever scrub up? I need some confidence in POP..
For the last 2 days my numbers have been.....
FC 13-16
CC 0-0.5 mostly 0
pH 7.5-7.2
TA 170
CYA is now 38 (for the last day or 2) previously was lower...

Because of frustration I thought about getting FC up to 18-19 for a day or two and then having another steak party with all 3 kids scrubbing...
Because it is dark I will get some pics tomorrow of the brown streaks/stains....

 

[JasonLion]

If there is something that won't scrub away, it isn't algae. Algae will brush right off.

This sounds like organic staining to me. Organic stains are sometimes left behind by algae or by leaves that sit on the liner for a while. Organic stains should fade slowly over time, more quickly when you maintain shock level, but even then it can take a while.

 

[GuinnessPhish]

If you think CYA is 38, you probably should raise FC to around 19 or 20, and maintain it. There's a good chance, CYA might actually be higher than what you think, as it's such a subjective test.

 

[ranger_ric]

I definitely had leaves sitting on the liner all winter. Would "Organic Stains" prevent me from passing the OCLT?

 

[duraleigh]

Would "Organic Stains" prevent me from passing the OCLT?

Hard to say. A really imbedded stain is not very consumptive of chlorine (that's why the stain remains) but it could certainly have some affect. If that was my pool and I had crystal clear water, a cc's of .5 ppm or less, I would do the OCLT and report the results here.

If you don't have both of the other two criteria, keep SLAMming.

 

[ranger_ric]

Well last night we passed the OCLT. I am however going to keep my FC at the higher level of "normal" until I get these stains scrubbed up. Thanks to Everyone on TFP for your help.