I'm killing cyano with light

[Europhyllia]

Isn't that the weirdest thing?

I just upgraded from my 4 bulb T5 to a higher quality 6 bulb T5 fixture (which I love by the way - no regrets about the extra expense now that I have it).
I only got it a couple of days ago but it's wiped out the cyano I had on my sandbed (mostly low flow areas where I target fed the mandarins)
The red is gone. Little bubbles are rising from the sand and leaving behind just white sand. So something is obviously being metabolized very quickly.

I always just heard cyano happens when there's not enough flow -in fact I have a couple of Seio Superflows on order just for that.
But I didn't change anything other than the light!

Why/How would that get rid of cyano?

[Gseclipse02]

lucckkky!!!

[allan]

Going out on a limb, but could it be that your old bulbs had shifted to the red area of the spectrum? Don't know if that would affect cyano, but it seems to a contributing factor for algae.

...or a reasonable hypothesis would be, as stated by G above, "lucckkky!"

[Europhyllia]

Yes Allan. I was all excited thinking I had discovered something new but apparently cyano does like a certain red spectrum (580 or so). I'm guessing the current bulbs (including some from the old fixture) have less of the 580 the cyano likes...

[allan]

I had a huge bloom in my tank. I had to shut off the lights for two days and I put in another K4. Sand was kind of fine for flow, so I aimed it towards the surface for agitation. My reasoning is that by increasing oxygen in the water I could combat the slime on two fronts.

I still have some minor stuff on top of my rock work... can't see any, but the tell-tale bubbles are visible at the end of the day.

[Europhyllia]

My reasoning is that by increasing oxygen in the water I could combat the slime on two fronts.

How does the oxygen affect the bacteria?

I am asking because even with decent alk levels my pH had been kind of low so I did the aeration test and apparently our indoor air (and the tank) had a lot of CO2 so I got a hose and connected one end to the skimmer air intake and aimed the other end out the window.

My pH is much better now. I am assuming my water has more oxygen and less CO2 now. Could that have done something to the cyano?
Maybe that's what happened because with the outside air the skimmer also seems to be more bubbly/productive...?

[allan]

I'm just using a bit of reasoning that could be wrong, but if the cyano was generating oxygen, that would mean it consumes carbon dioxide... but I'm just guessing here.

[Kristy]

Improving pH definitely discourages cyano!

[GoneReefing]

I am battling this stuff right now in my 20gal. It seems to pop up as soon as I replace my stock lights with 2 ATI Aquablue+ and 1 of each UL AquaSun and Super Actinic. So I tuned back my light time down to roughly 8 hours or so and been doing water changes weekly but it still there. I guess next step would be to get another pump to increase the flow. Is there anything else I can do?

[allan]

The only other thing that I did that might be attributed to killing mine off is the uv sterilizer, however it doesn't make sense to me if the cyano is on surface stuff then it's not in the water column. Biggest impact was turning off the lights for two days.