I got the following email reply from Yi Hu Fish Farm with regards to the same question that I asked them sometime back :
************************************************************
Dear David,
Greetings. You enquiry in regards to your Eheim 2026 in referred to me. I would say that the only piece of material you need to change in your filter would be the mechanical filter medium (white filter pad). Do not partially wash it, change the whole pad after every 2-3 months.
Leave the blue filter pad alone as it is a coarse filet pad (biological filter medium) and the beneficial bacteria will dwell on it. If your water quality is alright, you may not need to change this pad at all. If not, change this pad every 6-9mths. Always remember not to rinse you filter mediums under tap water. Rinse them with old tank water.
Hope this helps.
************************************************************
As for the substrat, I would removed 1/3 of each and top up with new ones every year.
Bookmarks