I think thats the same media I use... little balls of what looks like the inside of a "crunchy" chocolate bar ? If so, heres what I do.
Firstly, I ONLY clean it when its needed... ie when the water flow from the outlet drops.
First I syphon all the gunk from the tank bottom - and throw away, then I syphon only water into a bucket and then remove the filter and take the whole lot outside (2234) My media is in baskets - not sure about yours.
I disgarde the top white filter pad - its usually the one thats choked with gunge... I do NOT buy Eheim replacements as they are very over priced, I goto a shop that sells material, and buy a metre of "wadding" its exactly the same stuff, only 100th the price ! Cut out the circles with scissors - get dozens of em !
Right, now I slosh the baskets about in the filter housing (still full of water) and tranfer to the bucket of water - again lots of agitation... disgard both the filter housing water and the bucket, you may have to repeat the bucket of water from the tank wash (easiest way is to use the inlet hose to remove more tank water)
You are not aiming to get crystal clear water, just relatively clean... once the majority of gunk is out of the media - only take a couple of minutes, I replace the baskets, pop on a new white pad and replace the lot into the filter body... a quick check that the power head is not caked in grime or blocked... needs sorting obviously if it is... I find a nail brush and/or toothbrush a handy tool (errr, get a new one JUST for the tank !) to have.
The rusultant soup smells foul - hence I do it outside, and if you dont have a strong stomach you might like to wear latex gloves too - especially if you bite your nails ! LOL
Re plumb it into the pipes, and prime the system - you MUST ensure that the filter and inlet pipe are FULL of water before turning on the power.
Whole thing takes less time that this took to write... you'll soon get the idea.
Take a little extra time checking the pipe couplings and taps - trust me its easy to overlook something.
You cannot really over rinse the media, just make sure its in OLD TANK water and NEVER tap !
Good luck...
