Dear Editor,I read with interest Roger Machmeier’s response (October 2010 Septic System Answer Man). I don’t take exception with anything he said but in fact agree with all he said. However, in explaining the problems caused by porous concrete I would have expected a more in-depth explanation of why concrete is porous and/or steps that could be taken to help solidify the concrete. The factors influencing the porosity of concrete are numerous. Maybe he can address these factors in a future issue.The use of excessive amounts of water can create increased porosity. Since septic tank wall forms are normally narrow (2 1/2 to 3
