Refractometer vs hydrometers (1 Viewer)

[mushroom fishes]

So here is my dilemma I just got my refractometer and calibrated it with the included solution. This is where my problem begins. I have 3 hydrometers one that stays in the tank and 2 marineland dip style ones. one newer and one older one. All three are reasonably the same at 1.024 I try to keep my water at 1.023 so pretty good I think but just checked my water three times with the refractometer and it says my water is 1.020. so question is what do I believe? Can't imagine three hydrometers that read roughly the same can be wrong. But allot of people say refractometers are much more accurate.what should I believe and if I should trust the refractometer i'll need to up the salinity what's the best way to do that without hurting the fish?

 

[ikserk]

To increase gently, either do a water change with elevated salinity, or add a little salt to the top off water for a bit

I would trust the single properly calibrated refractometer I've three hydrometers that agree with each other

My gut tells me that if you were to fill the hydrometer with the refractometer calibration fluid, it would read high.

 

[RSnodgrass]

Yup recalibrate. Then I put an etch mark on the hydrometer for where I want it to be.

Definitely rinse your refractometer with RO water after using or before using if you can.

 

[infinityends]

What type of system are you running? Fish only, Fish only with inverts, or a Reef system If you are just keeping fish, nothing to worry about even if the SG is 1.020, I keep my FO system around 1.020-1.022 because it saves a little money on salt. Lower salinity also allows for more oxygen in the water, so if you don't need the higher salinity for corals it can be beneficial to run a system with lower salinity.

Admittedly, not sure what salinity is required for inverts since my FO system doesn't have any inverts.

Hydrometers can be skewed by micro bubbles, calcium buildup, etc. Refractometers are generally more accurate, but do need to cleaned with RO and calibrated and a fairly small bump can throw them off. The Hanna Salinity tool ($70) has a lot of good reviews, I haven't used it personally though.

 

[mushroom fishes]

What type of system are you running? Fish only, Fish only with inverts, or a Reef system If you are just keeping fish, nothing to worry about even if the SG is 1.020, I keep my FO system around 1.020-1.022 because it saves a little money on salt. Lower salinity also allows for more oxygen in the water, so if you don't need the higher salinity for corals it can be beneficial to run a system with lower salinity.

Admittedly, not sure what salinity is required for inverts since my FO system doesn't have any inverts.

Hydrometers can be skewed by micro bubbles, calcium buildup, etc. Refractometers are generally more accurate, but do need to cleaned with RO and calibrated and a fairly small bump can throw them off. The Hanna Salinity tool ($70) has a lot of good reviews, I haven't used it personally though.

Currently mostly damsel fish three clowns and one sand sifting goby. For corals mostly leathers and mushrooms and one anemone that's what I've got so dar

 

[Rendgrish]

I agree with the others- if you checked your refractometer with calibration fluid, the hydrometers are off. With the anemone, you will want to be in the 1.025 to 1.026 range. Just top off with saltwater for a couple days and it will come up gently without stressing the tank.