I just got a new Refractometer!

[Diving The World]

Can you believe I've been in the hobby since the 80's and never had a Refractometer? Never heard of such a thing till this forum. Oh well, NOW I have one. But a question...

I calibrated the Refractometer with distilled water according to the instructions, dried it all off, and did a reading. It scored 1.023. Kinda on the high side...

My old Seatest Specific Gravity Meters (I have two so I know I'm getting a correct reading...or not...) show 1.018.

That's a HUGE difference. Is that possible? I assume the refractometer is correct and the crappy plastic hydrometers are wrong, right?

[Diving The World]

One more question...

What's the best over all specific gravity to maintain for a reef tank? I plan to eventually keep LPS, SPS, Zoas, Clams, Fish, etc. Thanks!

[Fly Guy]

Its not uncommon for that much of a difference in reading between the two

FWIW 1.023 is LOW though. .025-.026 is where you want to be. If you decide to raise it......(and you should), do it simply by adding asw instead of freshwater to top off until your there

[Diving The World]

That's interesting. Over the years I've always maintained 1.020 - 1.022 which on my crappy hydrometers was probably around 1.025 - 1.027...

So 1.025 - 1.026 is a good over all reef tank specific gravity? Thanks!

Now, I just need to slowly start raising it...

[Sprayin70]

Congrats!!! I couldn't live without mine!

[jenajet]

yep, my hydrometer read 1.025 but when the lfs check for me with the refracto 1.030! And I wondered why nothing was opening up! Running on the low side actually worked for you so when you checked you were pretty close to normal.