thanks Ian, yeh the flow in the tank seems to have dropped now the filter's been running for a while, it's a 2213 in a 10g so I figured there was enough turnover with that. I've been dosing liquid carbon, but prob not been consistent enough with the dosing, I need to drop past a chemist and get a new 3cc syringe. With the external filter can you completely clean out the foam filter pads to get the flow back to the original level without losing too much bacteria? I presume most of it is in the substrat pro which is the only other media i have in the filter, other than the three standard sponges.
Andy