Quetion #2 about refractor

[ANNIESREEF]

I purchase one of those refractors from Drsfosterandsmith for $42.99. The instructions say to use drops of distilled water before applying water from the tank to check salinity. Wouldn't RO water be just as good since I do not keep distilled around?
Dumb question but I need to know...:rolleyes:

[Hop]

Yup. RO or RO/DI will work fine to calibrate it.

[HippieSmell]

Even tap is good enough.

[ANNIESREEF]

Thanks ya'll...