I agree definately get a refractometer money well spent. And Temperature affects the reading even with the ATC
. My RO
unit is connected behind my washing machine and the line runs threw a hole I drilled into the wall to my 32gallon trash can where I store RO
water with a heater. Than I have a 20gallon trash can I use to mix saltwater. I take water from the 32G to the 20G with a Pitcher. I fill the 20g close to the top. And then I add exactly 19 scoops of Reef Crystals. I comes out perfect everytime. After 24 hours of sitting with a powerhead and heater its ready to go. I usually refill both cans after I do the PWC
so the water actually sits for about a week.