Cause of Cyano?

[JonoB]

I posted this on a different forum but figured I'd ask the "experts" here, too

My tank has had a good bit of cyano this past week. My wife and I were in the hospital having our first child (woot woot!), so I wasn't "up" on my siphoning. It got a little crazy, but I've siphoned most of it out now.

A little more background, my fish have all been in a hosptial tank for about 8 weeks now, so I know I haven't been over feeding the DT. I throw a tiny amount of food in for the inverts, but not what I used to for fish, obviously.

So my question is this: What is causing the cyano? My parameters are all in check, 0 ammonia 0 nitrites, less than 5 nitrates (almost 0), 0 phosphates. I have checked my parameters before, immediately after, and a good while after water changes and its all about the same.
My only thought would be my MH bulbs, I've read that old bulbs can emit more of a red spectrum and cause algae and bacteria blooms, but wouldn't they still need nutrients?

What are your thoughts?

 

[Retro Reefer]

Sounds counter intuitive but I had cyano for over a year in one of my tanks and nothing I tried got rid of it until I substantially increased feedings, pulled GAC and stoped skimming 24/7.. cyano quickly disappeared and hasn’t returned.

 

[JonoB]

I've kind of wondered if it had to do with my lack of fish and slim feedings. Also, I understand that "new tanks" have these problems which is a common answer, but I like to know why.

 

[Scrubber_steve]

So my question is this: What is causing the cyano?

Perhaps you can come to some conclusions here -
Cyano going to cause me to shut down my tank

Where exactly is your cyano growing? just on the sand, or the rocks too?

 

[Idoc]

Check your source water... when i changed my filters and DI resin, most of my cyano and diatom blooms went away and haven't returned. Also want to look at flow. Then again, if it's a young tank, it's going to go through this to mature.

 

[JonoB]

Thanks, I'll check out that link. It's almost all on the sand, but some on the rock.

I've recently changed out my filters and DI resin, and it's all still reading 0 TDS. It's a young tank. A 30 gallon long with 2 koralia 425's and an AC50. I've thought about getting another powerhead but didn't want too much flow.