Filter Mediums And Changes

Hi Eeyore. The general rule of thumb is not to change your filter medium unless you really need to (as Sue would say, only when they're falling apart).

There are a couple of exceptions with carbon being one of them - carbon is best run in your filter only when you need it, e.g. after a course of meds or to tackle a particular water quality issue such as discolouration, rather than running it permanently. The other would be filter 'floss' which can come in various guises but is generally a cotton-wool like pad that is there just to 'scrub' the water before it leaves the filter - these should be changed regularly, but unlike the other mediums are pretty cheap.

Otherwise, your filter medium just needs a clean every now and again - perhaps every couple of months (depends on how gunked up it is). In this case you clean at the same time as a water change by gently squeezing the sponges in the water you've taken out (don't clean them under the tap!). The resulting water will look horrible  but will be great for watering any house or garden plants you have 

Cheers! 

I don't think I can take the credit though as I'm sure I got the tip off here originally.

Yep! I've got far better apples this year from our little patio fruit tree.