Jiddy - I thought I might confuse you...sorry. I didn't want to get into too much detail because I was so tired. As the bioload changes in a tank, bacterial populations have to grow to meet the needs of the tank. Once they are reached, and the wastes or die offs are used up, then the bacterial populations will cut back a bit. The dead bacteria releases the nutrients when it dies, and algae is right there to clean it up - combine that with excess nutrients from waste that hasn't been processed yet, and/or die off from live rock.....YUM algae food! Then you'll see the algae die off, which sets off some nutrients and will fuel a new round of algae. New tanks get algae - all different types - that's part of it. Some tanks don't get it so bad, some get a ton of algae....it all depends on the nutrient load, and even with low nutrients you see blooms. You are skimming, so that's helping to remove the DOCs, when doing water changes - siphoning up the algae will help export the nutrients, too. Our tanks are ever changing....even once the nitrogen cycle is "over", there is still ammonia getting broken down to nitrite, then nitrate....it happens at a much more efficient rate, so you don't see a spike, unless you add too high of a bioload (i.e. put in uncured rock, etc). Hope this clears up a bit.