I have been keeping my FC around 4 since opening slam. I have noticed some yellow looking stains on the bottom. They brush away into a cloud of yellow. The water then turns a light shade of green. I am keeping PH around 7.5, however it was up over 8 when i tested yesterday so added acid to bring back down. Have not shown any CC since opening slam, even last this morning showed 0 CC. Not sure how to proceed since I am not sure what is going on. If it was algae would I be getting some CC reading? It appears to just settle on the bottom in crevices again after sweeping. Would the filter not get it out if it was pollen? Suggestions???