Specific Gravity Question

[jpc763]

Hi,
I measured SG in my new tank tonight. On the right side where the heater and a small powerhead reside it was 1.020. In the middle it was 1.021. On the left side where the overflow box, refugium return and large power head reside it was 1.022.
Is that normal to get 3 different readings in 3 different places?
Thanks, J

 

[myreef05]

No, it's the measurement device. Are you using a swingarm hydrometer or refractometer? If you have circulation in the tank there should be no difference at all.

 

[florida joe]

Temperature influences specific gratify readings

 

[myreef05]

Originally Posted by florida joe
Temperature influences specific gratify readings
to some degree but that drastic in 3 spots?

 

[florida joe]

Depends on your tank set up do you have slow water movement around your heater try taking temp at the locations you are checking salinity

 

[zanclus]

I would check it with a refracometer They automaticlly adjust for temp.

 

[jpc763]

I am using a swingarm hydrometer. I have made sure that the bubbles are out of it. The right side front of the tank is where the SG is the lowest. At the right side back (13") away is the heater and the small powerhead. The powerhead is circulating water from that corner to the middle of the tank. The left side front is where the SG reads highest. At the back is where the overflow and return flow, along with a large powerhead is located. Also flowing water from the back corner to the middle of the tank.
The temp in the water is 79 degrees.

 

[earlybird]

Still not going to get accuracy with a hydrometer. Sorry going to have to get a refractometer for accurate sg readings. $40

 

[jpc763]

Originally Posted by earlybird
Still not going to get accuracy with a hydrometer. Sorry going to have to get a refractometer for accurate sg readings. $40
Ok, I will get one. Any model or brand that stands out?
Thanks, J

 

[lexluethar]

Just buy the one from this site. You will be amazed at the difference in readings from a hydrometer compared to the refractometer. I thought my SG was around 1.025 with a hydrometer, once i bought the refractometer from swf.com it was around 1.019.
Also once you buy a refractometer use the right side - which is salinity instead of specific gravity. With SG temperature needs to be taken into account.