Peter John Keating wrote: > once the sodium hydroxide solution has cooled, add 5 gallons of > concentrated "acide chlohydrique" to 45 gallons of caustic. This brings the > ph of 14 to ph 9. > Once neutralised the solution can be poured onto the soil at an acceptable > site. Acide chlohydrique is probably HCl or Hydochloric Acid and is generally used with Sodium Hydoxide as an example of a strong Acid- strong Base reaction. The products are water and NaCl or table salt. But the starting ingredients are nasty. And in those concentrations I would pour very slowly and wear protective clothing and face protection. To me, it is just not worth it both from a safety and economic viewpoint. Bill Truesdell Bath, Me