Hydrometer- 2 brands/ 2 readings

[fastjunkie]

I've been using a SeaTest specific gravity meter for YEARS now with very good accuracy. Today, I happened to buy a Deep Six hydrometer from coralife,basically because it was on sale at my LFS. Anyhow when I got home, I decided to compare the 2 and WOW was I shocked!!! My SeaTest shows I have 1.024 and the DeepSix gives me a 1.032. Which one do I trust? They are both the "swing arm" type meters. I guess I'll be off to my LFS to see which one wins. I'm sure this thread has been posted several times in the past, but it is always something to consider when switching from brand to brand on any test equipment.

[LIONFISH5740]

Those hydrometers are only used by me to replace any water with the same SG. I don't trust their accuracy and they get worse with age. Especially if you don't rinse them out with fresh water afterward.

[DylanC]

I would get me a nice refractometer from ye olde famous auction site. They have them fairly cheap (i got mine for 24 bucks).

Hydrometers are fairly unreliable i have three that give me three different readings, none of them are correct.
The bonus of a refractometer is that no matter how much you use it it will always give you a correct result (provided it was calibrated correctly in the first place)

anyways lets hope that your 1.024 reading was the correct one!!

[Boomer]

That Deep Seas is the worst there is. However, you have had that SeaTest for years and has it eve been cleaned. I'll bet the Deep Sea is more on now than that SeaTest if it has not been cleaned. Salt deposits collect on the needle from evaporation and weigh the needle down so it reads low. Get some pH 4 buffer solution and soak it in that or Vinegar over night and rinse well in warm water, let it dry and test again.

[cody6766]

don't trust either one. Calibrate them against a good refractometer or get a refractometer. I did the former and my deep 6 is off by about .05.

[bertoni]

I had a Deep Six briefly. Very briefly. I agree that a refractometer or a conductivity meter is a good idea, but a well-maintained hydrometer should be okay. There are test solutions that you could use to check yours. The PinPoint 53 mS solution is useful for this, or there's a DIY recipe:

http://reefkeeping.com/issues/2004-06/rhf/index.htm