red stringy stuff that smudges

Is it algae?

I cleaned up the pool after a good thunderstorm. There was a lot of debris at the bottom. The water was clear and my numbers have been consistent.

FC between 2 and 6 (I know that 2 is a little bit too low)
CC always, always 0
CYA 30
PH 7.8 (I keep bumping it down but with Alk at a high 230, it keeps creeping)

I gave a half-hearted attempt to do Ben's Alk lowering process but didn't have the time to monitor it. So, I just keep adding acid to lower ph until I can devote an entire weekend to it.

As I said, yesterday I cleaned up after a thunderstorm by brushing the sides and vacuuming the pool bottom. The day was overcast and a bit muggy. I came back after about 3 hours later to find a significant amount of debris back on the pool bottom. I took my leaf rake and stirred some up to capture it in the rake and when I brought it out, it looked to be reddish-brown in color and a bit stringy. I touched it and it smudged into the rake fabric. There was nothing solid to it.

I've shocked my pool to over 20 ppm last night and will keep the FC at shock through tomorrow but I'm not real sure its algae if my CC has been 0 for the past month. The only time it wasn't at 0 was upon opening and it only took 2-3 days to get it to 0.

Thanks for your opinions and help.

On another note, I think the Algae message board needs to have the color of algae in its subject line. I looked at several pages and didn't see anything that said red or reddish-brown (lots of yellow, green and black however).