Ok not to sure if this should have gone into the plant section but, does anyone know what bright green algae is a sign of?

Its not like the normal green algae, its greeny-blue(bit hard to explain).

It has started to grow over my gravel, i can clean the bottom but it comes back after a couple of days.

It started to appear after i put some slate rock that was on my deck into my aquarium. Any ideas? the water tests ok for ammonia and nitrite, and the nitrates are acceptable, its got me baffled. :-?

I have had this algea also, never seen it prior and even at 0.5 ppm phosphates it was still present

My fish seem ok.

so far.

Does it form a slimey sheet over things? If so, it is cyanobacteria and not an algae.

I don't think it was blue enough to be cyno

I don't know about forming a slimey sheet but I found it grew on the gravel and then started smothering my ambulia

a customer of mine had the same thing

No, but i reackon if i dont do a gravel clean for a while it prob would.

So if it is cyanobacteria, what does this mean?

It means you need to buy some black market E off your friendly local dealer...

(E=Erythromycin Works great)

Use with care (E, I mean)

As Wok says you need to be very careful using Erythromycin, it is an antibacterial and will kill your filter, plus you can't buy it so unless you can find a friendly vet or someone with some you would be out of luck. Also because you can't buyy it as a treatment it's a bit hard to know what the correct dosing would be. IMO it will work but doesn't treat the course. Now you know what it is a suggest you do some research and identify the problem and work on fixing that.

Take a look in the Plant section under Furran 2. A similar topic has just been discussed.