NFT algae problem

[Steddie]

Hi there,

I have an NFT system running in my greenhouse - first time growing
hydro.

I think i've been sloppy keeping the nutrients light-proof and seem to
have some algae growing on the root zone.

I uploaded <a href="http://www.e-ds.net/IMAGES/nft-alg.jpg"
target="_blank">a picture here</a> if it's any help.

Can anyone advise if this is actually an algae infestation, how
serious/dangerous this is and what sort of remedy I could use?
(algaecide?). I understand that algae itself isn't particularly harmful
but tends to attract fungus gnats etc..

The water in the reservoir is straight from the tap, which is pH 7.7
that i adjusted down to 5.8

Thanks in advance!

[Steven Anderson]

Adding an air pump attached to air stone will help. Before using one we had algae problem. It is no long a problem for use. A cheap Wal-Mart air pump from pet supply. Our pump and stone cost under $10.00.

[Steddie]

I have an airpump/airstone in my reservoir, quite a small one but
hopefully sufficient. I've blocked out as much light as possible by
sealing the top lid with duct tape so hopefully the algae won't get
much worse.

I'm thinking of getting some of this stuff
http://www.growell.co.uk/p/2477/BlockClean.html

Not sure whether it will be suitable for spraying directly on the roots
though!