SO i was wondering if anyone has ever seen BLACK Blue/green Algae??i found some on my substrate 2x now and i think one reason is because i have a lot of Flourish Black Sand mixed with a little bit of regular sized aquarium rocks and i think it just wasn't turned cleaned with the "wand" thing. but the reason i call it blue green algae is because it grows like it sort of blankets it but it stays low to the substrate. So i was just wondering if anyone has ever seen this??? oh and i have seen some on my Java fern wendlove that's attached to the top of my driftwood near the lights..but i cant find any info on this one. i do have a little bit of regular blue green algae i found in my tank last night but it looks normal green. thanks!