Is this a good deal on ppm meter?

Any thoughts or experience with this ppm meter?

TDS Meter Inline Tester- Dual Mode Reading - Easily Installs Inline - Very Simple To Use

I would shit through it and have one analyze my shit up my ass and one as it falls to earth.

sounds like a good deal to me, i seem to recall inline meters being 100+. Would be a pain in the ass if you have to test more then one system, and you wouldn't want to hook it up to a line that goes to the plants, maybe just on it's own pump and a tube that goes back into the res. Any other way seems like it would be hard at res changes.