NTPEP APPROVED - GTX-2013-01-042. GEO 230 is a woven monofilament filtration geotextile made of 100% high-tenacity polypropylene yarns. GEO 230 resists ultraviolet and biological deterioration, rotting, naturally encountered basics and acids. Polypropylene is stable within a pH range of 2 to 13. GEO 230 will satisfy the requirements as outlined in AASHTO M-288-06 for Permanent Erosion Control & Subsurface Drainage (<15% fines) and meets the following M.A.R.V. values except where noted. Click here for Product Data Sheet.