Johns last blog post..Is It Confusion That Prevents People From Starting Or Something Else?

It is strange, isn’t it!

The easy cop-out explanation is that the nutrients in the refugium have been taken up by the introduced algae and there is nothing left for the hairy stuff .

So why is the display tank under the hairy attack? The bulb is new so there should be a correct spectrum and, in addition, I note that the bulb is 14K which, as you know, is more towards the ‘cold’ or blue, not lower down in the 6K or lower range where there could be more red, one colour that hair algae likes (as in sunlight). The circulation will be to its liking within reason.

I could suggest detritus, dirty sand bed (if any), overfeeding, overstocking and all the rest. I note though that you are experienced so those are unlikely – so don’t be offended.

One thought is I wonder if there is a very slow flow between the refugium and display tank. This would mean lesser exposure of all the system seawater to the algae.

If you have a sump in addition could that be seeded with Caulerpa or whatever? That might help.

Hair algae, even when starved of nutrients, sometimes is really obstinate and takes its time to depart. This may be because as it dies it again produces nutrients? The nitrate/phosphate may be gone or reducing.

I’ll have to let my brain cell trundle along with this one! Maybe I’ll sit up in bed at midnight and shout ‘Eureka’ and scare my wife!

I had set up a new tank with a refugium. The main tank was lit by 250watt 14k Iwasaki. The bulb was brand new. My refugium was lit by an one year old 65watt PC bulb. I had the typical algae blooms but not where one would expect. I started off my refugium with a very large ball of Chaetomorpha. During the cycle I had large quantities of diatoms and hair algae in the display but my refugium was clean. Both my micro and macroalgae were growing at a fast pace but in very separate areas. I cannot figure out why my refugium with such an old bulb was absolutely void of microalgae and growing my Chaeto at a fast rate. My main tank with very high flow and brand new 14 bulbs had massive amounts of hair algae. This leads me to believe that macroalgae can deter microalgae not just by out competing it of nutrients but also by something else. I’ve been around SW aquariums a long time and I can’t figure out what is going on.

Instead look for the cause of the problem.

ie Hair Algae: Elevated Phosphates and Nitrates
ie Red Slime Algae: Elevated Phosphates (not Nitrate dependent)