For how long you have BioPellets? I have same problem Illumina, BioPellets with pale SPS colors. Reading through forums I've got a feeling it can be due to BioPellets combined with intense light from Illumina. Do you have UV module? I was advised do not go more than 20% for UV module. After 3 months I have removed BioPellets from system. Have few days - no improvements yet
so cannot confirm