Cyano troubles

[ZLogic]

I guess the title says it, I'm having a rash of red cyano in my tank.  I've always shot for zero nitrates, low bioload, moderate feeding, regular water changes.  I can't keep encrusters, they don't grow and die out, and the cyano.  I read that cyano thrives in low nitrate/phosphate environments so I added a couple new fish, waited a week, and bought Nyos no3 and po4 test kits.  Tomorrow I'm going to try adjusting the return flow and the wavemaker to try and account for flow, any other ideas?

 

Tank is 4 months old

Biocube 32

Chemi-pure green/purigen/floss pad in filter

Chaeto in fuge

Ammonia: 0ppm

Nitrite: 0ppm

Nitrate: ~10ppm

Phosphate: ~0.10ppm

[Toomanymatts]

Pic?

[seabass]

I believe that organic wastes (both dissolved in the water column, and as detritus on your rocks and substrate) are the main cause.  While the fish will help increase inorganic nutrient levels, they will also add to the organics within your tank.

 

A little cyano isn't a big concern.  However, you don't want it covering corals.  Maintenance might be your best weapon.  Siphon out the cyano that you can.  Use a weak pump, powerhead, or turkey baster to put detritus in suspension so that your water changes (and filtration) will be more effective.

 

Flow is almost always recommended to combat cyano.  It's effective because it helps prevent the detritus from accumulating on the rocks and sand (keeping it in suspension to feed corals and to be removed by filtration).

 

The added nutrients will be appreciated by corals.  I'd shoot for 0.05 ppm to 0.10 ppm phosphate, and 5 to 10 ppm nitrate.  With higher usually being better than lower.  If you are having problems keeping nutrients up, you might wish to discontinue your chaeto refugium.

[ZLogic]

Circled spots are where I'm having cyano pop up, the upper area here is a new location for it tho, just started accumulating there in the past week or so.

[seabass]

I'd probably siphon out what you can; and take a turkey baster to gently blow the cyano (and detritus) off of the rocks.  If you siphon out any sand, you can simply rinse it out and return it to your tank.

 

I don't know if it's a real problem, but several people have reported issues with black sand.  Some say there is a higher iron content in it which can lead to algae (not sure about cyano).  I still feel it's mostly the organic wastes.