Hello All!

Let me start by saying Thank You too all that run and contribute to this forum. I found this forum and sister site, Pool Solutions earlier this year, and recently converted to the bbb methods after 4 years of the local pool store standard of bags of shock and algecide once a week and them testing my water. I purchased a K-2006 test kit and am testing my own water now and love the MUCH improved water quality I am experiencing using the BBB method! I have been reading as much as I can on the two sites to get up to speed, but still a huge newbie to my new found hobby.

Anyway to my questions. My pool water is clearer than it has been in a long time, however I have had this stuff show up on the pool bottom this week that looks like dead algae, but with a dark green/brownish color. It appears in the morning only after I add maintence Sodium Hypochlorite (12.5%). I have been reading many post here about Brown/ Mustard Algae hoping this is not what I have. There is a post with a picture that I cant see yet, that I would like to look at. The confusing part to me is that my chroline levels seem to be in tact. They are as follows:

Last night before adding hypo (7/20/11): FC=3.0, CC=0.4. Added enough hypo (per pool calculator) to take FC up to around 6.0, couldnt test to get an actual reading as it was too late.

This morning (7/21/11 1+/- hr after sunrise): FC=5.6, CC=0.2, CYA=50, PH=7.4, TA=170.. didnt test CH, but CH was teted on 7-15-11 at 180. If I got to around 6.0 on 7/20/11, I had a drop < 1ppm overnight, which should indicate no algae.. correct?

This evening when I got home (7/21/11): FC=2.0 (yikes), CC=0.4. Added hypo to take FC up to 6, let circulate for almost 2 hrs, tested FC=5.6, CC=0.4

Gonna test in the morning to see if I actually have less than 1 ppm lose to FC

Chlorine usage doesn't seem out of line?? Very hot day with usage. Does it make sense that it could be brown/mustard algae with these numbers? Its been two weeks since it has been shocked, and I have had a few days of evening test of FC less than 3.0. Always add chroline to raise FC upto +/- 6 immediately. I think I am going to shock this weekend just to be safe, the question is how hard should I hit it?

Another thought is could it be metals settling out? I top off the pool with well water, which we have a decent amount of iron. At pool opening I add a quart of staintrine (as recommended by local pool store) to care of the problem. I havent gotten an iron test yet this year, but have not had problems in the past when tested. I thought I read a post by Ben that he said it takes a very high iron count before needing to treat, so dont know how valid this thought is. Just throwing that out there.

Second issue/question, TA = 170. Per the book that came in my test kit, that is above the recommended range. But I read another post by Ben that with a vinyl lined pool that it shouldn't be a problem as long as it is below 200?? Should I start the process of lowering it?

Pool Specifics 24ft Rnd w/ Deep End (estimated at 18,000 gals), new 1 hp pump with 100 lb sand filter (yes..i wish I would have found this community sooner, manufacture said its good to 20,000 gal) runs 3 hrs on....3 hrs off.

WOW.. Sorry for the long post, what can I say...i'm a newbie learning.

Thanks Again!