Those figures are with rainwater, CO2 and a large quantity of blackwater extract.
I suspect either my gravel is leaching minerals or, more likely, I used to fill up with tap water (Bedfordshire=liquid rock) so I suspect there is a generous coping of carbonates deposited on everything which is being gradually broken down.
I suspect either my gravel is leaching minerals or, more likely, I used to fill up with tap water (Bedfordshire=liquid rock) so I suspect there is a generous coping of carbonates deposited on everything which is being gradually broken down.
