There is no need to ever change ceramic media. Most of us end up using the ceramic media because sponges and similar media do wear out and the ceramic doesn't.
Have bought biomax, can only fit a total of 3 in each doctored Elite cartridge, do you think this is enough? Have bought API Master Test Kit too, and ammonia, so will get my head around the 'fishless cycle' thread on here and have a go. Thanks for help everyone