Re: Retrofit Standing Column-what systems did you replace? I'm a geologist and have the water level meter (well its from my company). But you can rent them at an environmental and/or survey equipment rental place. Try searching the internet for one in your area. I think the place I rent certain equipment from charges $20/day for one. Part one of the test is complete and I'm analyzing the numbers. I want to do a second test at a different flow rate for correlation and comparison. Stay tuned.