Got a refractometer and WOW, way out...gotta fix

[wickedfrags]

Sounds like a reasonable plan. I would think 2-3 litres a day will do the job until you get it down to where you want it. Some people (inluding myself) maintain their salinity at 1.026 so you do not have to drop it down that much if you don't want to.

Originally Posted by Slick Fork

Hi there,

Just got a new refractometer in the mail today and wow was my hydrometer ever out. My Hydrometer was telling me I was at 1.024 and the new refractometer says 1.030. 6 POINTS OUT!!! I expected to see a difference but that's huge.

So anyways, I wanted to bring my salinity back down to 1.024 and my plan is really simple. I don't want to do it all at once of course but I figure if I pull a couple of litres of SW out every day and top back up with fresh RO water that should be slow enough do you think? The system is a 100gal display with ~40 gallons in the sump.

Is my plan to aggresive, or to conservative? Should I maybe just do my adjusting during water changes? Let me know what you think.

Cheers

[Reefer Rob]

Double check your refractometer with Pinpoint 53.0 uS calibrating fluid. Many of the refractometers that find their way into the aquarium trade are for testing brine not sea water, and will give you an inaccurate salinity reading

[Slick Fork]

I ordered it from J&L so I would hope that it's one meant for the aquarium trade! I did calibrate it with the "ultra pure" water that came with it. Is that alright or should I locate some of this pinpoint 53 stuff?

[Okguy]

I would confirm the refractometer readings first before making changes. Take a water sample to you're local store (if there is one around) and have them confirm the readings. If the livestock doesn't appear to be stressed with your current water parameters, you might as well take your time and make sure the changes are required.

I once made slight changes because a new thermometer I bought was faulty and the consequences were pretty severe. Just better to be safe than sorry.

[Slick Fork]

Unfortunately there's no LFS around that deal in SW stuff. Closest would be Calgary and that's a 2hr drive for me. Are there any other ways I could confirm the reading? Livestock isn't visibly stressed at all so I'm not in a panic, it'll just bug me now that I know about it!

[Reefer Rob]

Stability is more important than the actual level. A reading of 1.030 on the refractometers they sell at J & L is probably about right, as they read high. They also sell the 53 uS calibration fluid.

For more info read this thread

[ron101]

If the readings are accurate and you want to drop from 1.030 to 1.024 you will need to swap out about 25 gallons total (assuming total volume of 125gal) - more if you are doing it incrementally.

If you use RO water you will probably have to supplement more calcium and carbonate additives to keep overall levels up.