Changing media in Eheim classic

no socks or bags, please

The instructions say quite specifically to not use any sort of bags in the Eheim filters.

I found that if I put one of those hard blue Eheim sponges in between the noodles (on bottom) and the white rocks (on top) that it was pretty easy to clean.

I'd take out the top white pad, throw it away -- replace with cut to fit white padding to save money, then pour out the efisubstrat (white rocks) into a large bowl or bucket. You can hold back the blue pad with one hand as the top layer is poured off. Then take out the blue pad and just run tank water into the canister and swish around the noodles to clean them. And clean the blue pad, then the substrat too.

In fact, if you open the valve on the line that returns water to the tank, and use that to drain a bit of water to clean the tank you will be backflushing the tubing and it will stay clean longer. Eventually you need to do a major cleaning of the tubing, but backflushing it helps quite a lot.

If you use Ehfisubstrat as biofilter medium, the topmost ultra-fine pad is the one item in the filter which should never be substituted with lesser material. Without the very fine porosity and suprerb entrapment of microfine glass shards, you are endangering the impeller housing through abrasion. Wear there can require replacement of the entire head of the unit, a major cost and long delay. If you do not use Ehfisubstrat, the ultrafine white pad is not an issue.