We just completed this project last December. It was a fun and unique project. The Aeralater unit (removes iron and manganese) began to leak from the steel base plate about 3 years ago at a rate less than 1 gpm. The tank leaked as much as 30 gpm or about 20% of daily need prior to this project. It was cost prohibitive to correct this from the inside or by replacing the bottom section - cost range from $200k to $350k. So we came up with this "concrete curb/ring wall with chemical grout water stops" solution at a cost of $35k. The intent is to contain this until we can secure funding to replace the whole unit in about 5 years or so.