? refractometer vs hydrometer readings?

[murphreef]

ok well ive only ever used a swing arm hydrometer since starting

i have a mixed reef tank with sps, clams, softies, and LPS

using the hydrometer the readings always came back 1.025

i got my new refractometer in the other day and tested it the reading came back at 1.029.... is there that much of a difference between the two and can it be possible for the big difference and which one should i believe???

can this also explain some of the recession in my sps and some of the ones ive lost??

thanks!

 

[minimalist]

The refractometer is correct. SLOWLY bring it down a bit.

 

[murphreef]

how can the hydro be off so much??

could this be y my sps are suffering?

ive lost a few pieces lately and had recession in others

all my other paramters seemed fine

Am,Na,Ni all 0
PO4 was undetectable
Ca was 450
Alk8.3dkh
temp 80
mg1450
i have 25-30x's turnover in the tank too

could a salinity of 1.029 damage sps but be ok for softies and otehr corals??

y would anyone use a hydrometer if they are off that much?

 

[minimalist]

They're cheaply constructed. You get what you pay for. That could very well be the cause of poor coral health.

 

[murphreef]

well that sucks then!

im guna slowly lower it and see what happens then

hopefully the sps i still have will recoupe

 

[Weatherman]

Even with refractometers, it's a good idea to verify they are calibrated correctly.

Test some RO/DO water or tap water. It should come out to 1.000

 

[murphreef]

yeah thats exactly what i did with it when i got it put some DI water on it and made sure it was at 1.000

then tested my water and it came back at 1.029