We have cables tying the top of the cistern walls together, to prevent them from splaying out, but we wanted to do something at the base, to withstand the pressure exerted by the water and prevent any potential blow-outs.
On the north, east and west walls, where space is not an issue, we stacked rocks about a foot and a half deep and tall against the sheet metal walls. We will cover these with earth.[flickr_set id=”72157627618065336″]
It is now safe to add more water, as it is strong enough to withstand the full 7000 gallons that it can hold. This will serve as the water soure for the Food Web model
We made this tank square due to the liner we had, but circular is better, for so many reasons. The potable liner we have for the house system is round and we will begin on it in another couple of weeks, with full instructions of course. The main thing with round is that it is so much stronger, and with a couple of hat-bands on the outside, there is no need for added support.