need more fitration on the big aro tank so have modified an old 200l plastic drum i used to store water in
trimmed down an old plastic milk tray for a base to the filter
cut some offcuts of shower lining to fit inside as a central divider
lightly sanded the plastic to help the silicon to adhere to sides
pushed the drum out of shape a bit to get a tight fit
filling with pumice pieces in layers for media
no more nails, screws and some dowels work wonders on the compressed cardboard
also 25mm quare pine helps to hold and predrilling the screw holes helps a bit also
as smidey said doing a good job the first time will help it last