Didn't bother going any further with the test...

[Lance]

Originally Posted by asylumdown

In most cases (and yours, most likely), people have phosphate well in excess of the redfield ratio relative to nitrates, so after the biopellets reduce nitrate to trace/undetectable levels, they're left with the balance of phosphates that can only be brought down by GFO. I've been running Biopellets since day one, and without GFO, my phosphates can climb as high as 0.08ppm (tested by hanna), while my nitrates stay undetectable.

Same here. I find running Biopellets and GFO the best way to go with my tank. By running both I can keep PO4 and NO3 at satisfactory levels. I use about 750ml of GFO and have to change it out about every 5 to 6 weeks before PO4 levels start creeping up.