I buffer mine up with hard water but I maintain a 6.8 - 7.0pH on average. Got a good harvest of tomatoes last season 15 per plant.
I am shooting to set up a 1000 liter fish tank and a 4X16 foot float beds in ferros-cement. I will setup a three part filtering system using three 30 gallon drums, cyclone filter, particle filter and bead filter for bacterial conversion of the Ammonia and Nitrites. I will also put over it a hoop house with plastic on top and netting front and back and sides. fish tank will be mostly in the ground and light will be restricted as much as possible to the water so the UV does not kill the bacteria. The bacteria seems to be light sensitive.
My camera was finally repaired and returned so I plan on having pictures and videos of the construction and setup. I will jump start the system with the water and gravel from my current system.