New tank hair algae. reasons?

[aliaird]

I've got a new tank, approx 3 months old and have an outbreak of hair algae, which websites say is sometimes normal in new tanks.

However I'm not sure why really. I use RO water, instant ocean salt, have a skimmer, MH lighting, and have only two clowns in there (only just gone in).
I also have a phosphate remover in the sump doing its thing. Nitrate, PO4, etc are all zero, but obviously something is producing them for the algae to take off like that.
I set the tank up with cured live rock and added a 2-3 inch sand bed before leaving it for 2 weeks whilst I went on hols. When I returned I put the lights on again (they were off for the hols) and the algae started appearing.
The other thing I've noticed is that the problem seems to be worst at the back of my tank where the water flow is least (and also is the most difficult to remove detritus from?? - possible connection? But what is producing detritus?)
I have 18 snails and 6 (maybe 5 now) red legged hermits to munch waste/algae but they don't seem to fancy the long stuff, so it's hand in tank time. I want to get an urchin to tackle it and am confident that I wll get on top of it so I'm not worried as such yet... but I'm curious to know why new tanks with RO water, skimming, good lighting etc have this problem. Is it just that the biological filtration isn't at full pace yet? But with so little in the way of waste producers at the moment where is the nitrate coming from? I don't have any mechanical filtration or a wet/dry.
Any suggestions?

 

[Anonymous]

hi aliaird,

yeah, it is pretty normal for a tank that age to have a hair algea (HA) outbreak. HA uses nutrients from the water - typically phosphate and nitrate. it likes to grow in areas of gentle current. and, as you have found, it is tough to find animals that really like to eat it.
now, you may be wondering if your levels test zero, where is the HA getting the nutrients? i have found HA acts like a nutrient sink (or storage place). if you test your levels they come up zero. but if you scrape the algae, then test you might find the breakdown of the HA released some of the stored nutrients back into the water. your might find some readable PO4.
i had this problem for 18 months. to get rid of it, i had to harvest the HA to death. i went in with a toothbrush and scraped the HA off rocks, glass, whatever. as i did this i sucked the loose stuff out via siphon.
then i did a water change w/ RO water and kept the skimmer clean and efficient.
after a few weeks the HA had no more fuel. i found snails could keep up with the very short growth HA, but not long stringy stuff. so as i harvested, the snails would help keep areas clean.
it is a tough, tedious battle - but one that you can win. took me forever to get the RO unit, so i think you're way ahead of me.
good luck.