grabbed an HM digital TDS-4 off amazon - paid around $17? and another $10 on the calibration solution...probably overpaid for it all for the purpose being used but eh! seemed pretty close to accurate after getting it adjusted - close enough for the intended purpose at least!
took this as a chance to do a science experiment with the kiddo (her plants technically!) and she put together a lil science report for her teacher about it. we took guesses as to what the best to worst would be, tested it and I helped structure the report for teacher and let her come up with what to put down! without further ado:
rain water collected off carport dripline: 3PPM
pur water filtered water in fridge: 80PPM
kitchen / bathroom sink well water: 98PPM
pond water from small 1/2 acre pond outside: 128PPM