So I finally got my Eheim 2217 setup!!! What a beauty, I love it already....however, I am just curuious as to how long should I run my 3 HOB filters in regards to allowing for the bio filter in the eheim to get some good bacteria....any thoughts?
Try taking some of the media from the HOBs - cut a piece of the sponge for example - and put it into one of the lower trays. This will help seed your biological media. If you do this and run the HOB's for at least two weeks you should be fine - but I would keep at least one of your HOB's going for about 4-6 weeks.