Theres just one problem with that theory for my situation. According to my written records I've been using GFO steadily since 2008. In 2008 when I first tested phosphate in my tank it was .75, then with rowaphos I slowly made it undetectable. Since then I've maintained it low by changing out 1 cup of BRS GFO every month or two (My system contains about 240gal) In May 2010 everything looked the best it ever has and I received TOTM on this forum. In August 2010 and then again in March of 2011 I removed the GFO briefly and tried Biopellets. The first time it was 350ml and the second time 100ml. In each case I experienced bleaching immediately among the soft coral and then the montipora shortly after.
The Biopellets reactor wasn't discharged towards the return pump, just into the sump. My return pump draws about 2000gph and the skimmers pump might draw around 1000gph (PM Bullet 3 with Iwaki 70RT). So that could have been a contributing factor. However I think the main reason was that the tank was already an 'ULNS' with excellent growth, colour and undetectable nitrate and phosphate before I added the pellets. The pellets then stripped the last bit of Nitrate out which caused the coral to bleach.
I'm too Dutch to throw anything out so I sold the biopellets last year.
As I stated earlier, I had my system dialled in and running perfectly... then I tried to fix what wasn't broken... and then broke it so to speak. Now I'm trying to get things back the way that they were before the pellets.
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