soap in my tank?!

[clutterydrawer]

i got home today and my (fishless) tank had a cloudy film on the water surface which when broken up made bubbles and left a slimy residue on the tank walls...it looks quite like soap has somehow got in there, i have no idea how. what would be the best way to eliminate whatever it is? There are no fish in there so I can do anything however drastic! I just want to make sure it's totally safe for when I do get them.

 

[SirMinion]

Rotting vegatable matter and alkaline water can make a kind of natural soap that causes a scum on the suface of the water.
This is often seen on lakes and streams in the summer.
The easiest way to remove it is to float a lint-free absorbant cloth on the suface then lift it of. Rinse and repeat.

 

[clutterydrawer]

Hmm how intriguing...thankyou SirMinion

This tank has caused me more hassle before I've even got any fish in it that my other tank has caused me in three years!

 

[rdd1952]

I struggle with the same thing on my tanks. If I run a bucket of water and let it stand for 2 or 3 days, it forms the film too. An airstone keeps it broken up pretty well. I know you have already set up your new tank but if you do another, look into the fluval cannister filters. You can get a surface skimmer attachment for them and it keeps the film pull off. I am running 2 Fluval 304s with surface skimmers on my 75 gallon tank. it works great. I've had it running for aver 2 months and no sign of a surface film.

 

[clutterydrawer]

k I just dipped a bubble hoop into it, pulled it out, and successfully blew bubbles with it. That can't be just from a few days' worth of rotting plants or whatever can it?!