It looks like your original thread got side tracked with the tannins issue. From your pics (which are a tad small), I suspect you are experiencing brown diatoms.
The only time I get this problem is on a new tank which I haven`t used Zeolite on from the word go. The Zeolite adsorbs ammonia, and is great for keeping the ammonia levels down at the start of a tank, helping to keep any potential algae problems at bay, too.
Suspect traces of ammonia of ammonia in your tank, and think what may be causing them (immature filter etc). Fortunately, it can go with time, bit in the interim, try hitting it with a few daily 50% water changes to remove the ammonia and spores. It ids also very easy to clean off.
I hope the algae ID is correct from the small photos provided.
Nick, give Chilled a break.
He has started this thread because the original thread was sidetracked.
Dave.
EDIT: Chilled, keep the language in order, this is a family forum.