Cleaning Filter

I wouldn't use tap water, if you have chlorine it will kill off your bacteria. Just swish the media around in tank water from a water change. that should remove most of the debris.
As for your green water, that sounds like an algae issue. I assume you're testing your water since you're doing a fishless cycle. What are your numbers? Maybe your nitrates are high. Do you have alot of sunlight hitting the tank?

As said wash the media in tank water. You will not dislodge the bacteria in any amount that matters. Just don't kill it off with chlorine.

Algae does not/ cannot use nitrates. Algea does and can use ammonia very well. A common problem with fishless cycling is that people don't know to leave the lights turned off and they get a green water bloom due to the high ammonia levles and light.

To kill green water do a 100% blackout for 3 days. 99% blackouts do not work. cover the tank with something opaque, and make sure every available light source is blocked. when you incover it you will have nice clear clean water to look at. Plants will go through a 3 day blackout without issue, fish will as well if you have already added them. Your bacteria do not care if there is light or not. and Blackouts are free.
Dave

FishyTT said:

Also, the Eheim manual indicates that I just can use tap water to run through the media until it's clean. Is it safe to do this way?

Click to expand...

This is probably referring to when you first set the filter up, usually to rinse out any dust, etc. After you're running you will only want to use tank water, like everyone said

This is probably referring to when you first set the filter up, usually to rinse out any dust, etc. After you're running you will only want to use tank water, like everyone said

Click to expand...

This is also one of those "sometimes it's fine but I hate to reccomend it" things. tap water has varying levels of disinfectant, temperature, length of rinse, type of media etc. all come into play. additionally, in a traditional layered cannister with bio-media, it isn't as necessary to worry about whether or not you kill off the bacteria in your mechanical media. And tap water will usually get your sponges cleaner than tank water. So if your mechanical media is a significant part of your total bio-filtration then don't rinse it in chlorinated water, if it isn't do what you wish.

My sponges go into the maytag every week with bleach, oxyclean, and chlorinated water. BUT I have huge auxillary bio-filters in my tanks, and do not need or rely on my mechanical filters to maintain active bacteria.
Dave