Cyano?

I believe that it is probably safe to label this as being cyano, but second opinons would be great! I do have some questions because I'm not sure where this stuff is coming from. I have 0 ammonia, 0 nitrites, 5ppm nitrates, 0 phosphorus, and yet this stuff persists. One interesting fact is that it is completely gone by morning (when the lights are out), and then slowly builds to this level throughout the day. My lights are PC, about 6 months old. Does anybody have any ideas? Oh, yeah, my flow is about 1800gph in a 155 gallon tank.
thanks for your ideas!

 

a pic would be better for people to take a stab at it

 

ohh n/m, it took my pc a while to load for some reason, looks like diatomes to me... any others want to chyme in?

 

I knew that tank was bad news!!! Any ideas on how to get rid of it? My banded sleeper goby is spreading it ALL over everything.. The snails and fish like to eat it (ewww), but they areN'T keeping up with it... Is more flow needed?

 

More flow is always good.

 

the tank is relatively new.. 8 months, hmmm. only three or four hermit crabs, 5 huge turbo grazers, and a countless number if nasarius snails. the crabs NEVER come out of the live rock.. I have very few crabs because I have read that they eat small tubworms, and I like my abundance of natural filter feeders. Do you think I should get more crabs, and hope they come out of the live rock?

 

May also want to check the source of your water. Diatom algae uses silicates to form it's di-atom shell. So ensuring that your source water has 0 silicates is a must (also, most SW salt manufacturers add silicates to their salt to prevent moisture- this can't be helped). Secondly, diatom algae spreads faster in lower-pH saltwater, so also ensure your pH stays between 8.2-8.4, thirdly, lighting is always an issue for any type of algae. Judging by the 8 months your tank has been running, if your bulbs have never been replaced- time to do so!!

Good luck with the diatoms!