Planted Tank Guru
Join Date: Jul 2010
Location: British Columbia, Canada
Not sure I quite understand exactly what you did. From what I read, it seems like your tank was "dirty" in the first place. Is that correct ? When you say you let the filter stay in the dirty tank water, do you mean in the tank itself, not in the water you took out to rinse the intake tube pre-filter sponge ?
And all you did was rinse the small pre-filter sponge - correct ? Not the other media in the filter itself ?
If all you did was rinse the hell out of the pre-filter sponge, then no real harm done. That certainly wouldn't have destroyed all your BB - just perhaps what was in that small sponge - no doubt there remained a lot of BB everywhere else in your tank.
And why, if I may ask, did you put the black water that you rinsed the prefilter sponge in (that you had taken out of the tank) back into the tank ? That certainly wouldn't have helped your water quality.
Anyway, you did your WC and your parameters are fine. Check it a few more times over the next few days, but I'm fairly certain you'll be ok.
But I think you might need to adopt a more frequent, and more effective cleansing routine for your tank, if you'll pardon my saying so.
Iuse pre-filters sponges on my filter intakes, and rinse them well every 3rd or 4th day, and the water still comes out quite dirty brown each time I do that.