After time intensive research I am able to say: I know what's a reverse under gravel filter. Seems not to be common in germany, i didn't found more than 1 shop (well-known shop) selling supplies.
Unfortunately I only found descriptions from how to put in the tank, what you need (waterpump or airstone) but I have no idea why this is working and where the heck does all the water go?
Anyone here with a link, please?
*looking with big brown eyes around, like a small puppy*
Unfortunately I only found descriptions from how to put in the tank, what you need (waterpump or airstone) but I have no idea why this is working and where the heck does all the water go?
Anyone here with a link, please?
*looking with big brown eyes around, like a small puppy*