My lot# 5554 is on the recall list as well, brand new bottle that was opened a week ago. I literally just threw away the old bottle. I wish that I hadn't. Have had issues with the Alk testing low and having to correct it. I have lost most of my SPS corals, several LPS and zoa's. The Hanna meter is stating 8.9dkh. My Elos kit is stating 7-7.5dkh. Funny thing is a friend of mine had a meter as well, different batch(5341)of reagent and is using Red Sea and is getting 7.6dkh with it and 8.9dkh with his Hanna. Both of us have noticed red slime growth in our systems, indicating low Alk.
Also, yes I have noticed white stringy things floating in my last two bottles of reagent.