I cleaned out an aquarium completely, put in all new rocks, plants, decorations, etc. I cleaned out the cannister filter and put fresh carbon and media inside. I also used new air hoses and air stones for the under gravel filter. I filled the tank with water and it ran for 5 days.

Then last night I decided to get rid of the under gravel filters and use the air hoses to connect to other things for aeration. I would have thought that after 5 days, with NO fish, the water would be super clean compared to the condition it went in.

But as I was taking the air hoses out of the under gravel filters the hoses were slimy. It really surprised me since there wasn't anything swimming in the tank. Is this algae already, after only 5 days?

Yep or at least cyano bacteria

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

probably.. it grows fast!

I would have thought the water would have been good to drink after being filtered through carbon for 5 days and no fish in the tank. I'm glad I didn't try it.

I have the same stuff. Tank's been cycling (into 3rd week on Sunday) with no fish. Noticed the decor and glass was covered in an opaque slime. As long as it's good for the tank and will provide food for my many algae eaters, I'm happy.

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20g Heavily Planted http://www.aquariumforum.com/gallery...00&ppuser=8981
36g Bow Front Heavily Planted http://www.aquariumforum.com/gallery...00&ppuser=8981

I just ran in to the same issue too. Lol. Thought my driftwood was rotting cause it was covered with it, but if its harmless the plecos can have it when the tanks done cycling