"Texas, 1740 ppm is prolly better than distilled. MAYBE better than RO, depends on what's left in it after processing. That is some crunchy H2O, though. Thought mine was severe (it's about 740). Lemme ask Weezard to check in on this. I don't wanna lead anybody astray. I'm jes' sayin' what I do with my $25 Milwaukee POS pen. I'd hate to have you mess up a precision instrument following my questionable lab techniques! "

Crunchy is a good word. :thumbsup:

Ah dunno!
I'd guess that you'd risk lime deposits at that level.
Again ah dunno.
But, twere me, I'd use distilled water with plain ol' table salt, NaCl, sprinkled in to about 600 ppm.

And, on getting them wet?
(and feeding them after midnight)

If you drop in, or splash with, nutes, open it up right away and rinse the circuit board with distilled water.
D.W. is non-conductive, and will fix a hosed-up meter if you don't wait too long.
Blot it with a paper towel and let it air dry before replacing battery and you should be good to go.

Sounds like you guys are in good hands here.:thumbsup:
Carry on.

Exits, stage left.
Veezard-------