How to use hydrometer

[jmeunier]

Ok, this probably seems like a really basic question, but, how do I use my Instant Ocean hydrometer?

I'm brand new to keeping a SW aquarium, and I'm measuring the salinity for the first time. I'm finding the usage instructions that came with the device not very clear, so I'm unsure if I'm using it correctly.

I'm assuming that I need to fill it to the top, but does the little channel that's on the side of the unit need to be completely filled? Not sure if that's even possibly, since there's a cutout on the side that would appear to let the water drain out of the channel so that it's approximately 1/2 full (channel only).

Any advice? Really basic, I know, but I want to be sure that I get things right from a salinity and cycling standpoint before I add any livestock to the tank.

Thanks
Jay

[Fluff]

You need to submerse the hydrometer down past the cut out. The hydrometer will fill when the tank water runs in through the cut out. When full, set it on a flat level surface to read it. Hope this makes sense.

Open you garbage can lid, toss it in, and order a refractometer. You'll need one to be sure your SG is 1.009 (hyposalanity) when you QT any new fish so might as well bite the bullet now and get one. Can pick one up at Dr. Fosters ... for about $40. Good luck!

KG

[localhost]

Don't do like I did and submerge the entire thing into the tank. You will get too many bubbles on the needle/float to get a proper reading. Submerge it slowly until water starts flowing into the main chamber from the channel that fills from the bottom. Should work fine then.

[Scottm]

hydrometers are extremely accurate instruments when used right. make sure to get a sample from the middle of the tank, place it on a flat level surface and read the numbers then run warm water through it. Thats all. Mine is accurate to the nearest .0001 Which is more accurate then you need. Irecomend alchohol hydrometers but yours will work fine. Yes a refractometer is easier to read and usually more accurate but ultimately unecesary for the level of accuracy required.

No offense, but that's not true unless you're talking about the handmade lab grade German ones that cost as much if not more than a refractometer. The swing arm are OK at best for FO due to their high error rate be it mechanical or operator, but any good arsenal would include a refractometer. Just my O2.

KG

[No_Floaters]

Follow this link for a $35 refractomter from Foster & Smith. I usually don't do this..but you can't beat the price!

http://www.drsfostersmith.com/produc...f=2020&subref=AC

[malkore]

I used a bulb hydrometer, a swing arm, and finally tried a refractometer....and promptly thru out the two hydrometers.

[lasek2k1]

if u stick with a hydrometer, make sure u make note of this point.

not only do u need a flat surface, but u need a LEVEL suface.

if the surface slants to the right, you'll get a lower reading
if the surface slants to the left, you'll a higher reading

HTH

[Scottm]

that was my point most surfaces in houses aren't level. I use the edge of the aquarium as its the most level I can find. Testing against the refractometers in the lab its very accurate.

[dianeww]

Won't it hang perfectly evenly if you hold it up by the loop thing at the top? I assumed that's the intended purpose of that gizmo, it's not just decoration.

[BillyZ]

thats why I don't like the hydrometers. They are certianly accurate. But there are too many variables involved in my reading it accurately. That's why I prefer the refractometer's hands down. Don't have to worry about temperature of the water, don't have to worry about bubbles on the arm, dont have to worry about the box being perfectly level... just dip the pipet in teh water, put a drop on the lens and read.

hand's down, I would go with the refractometer.

But if the extra cash isn't available for you, take the advice given by many above, make sure it's level, make sure there's no bubbles on the arm and rinse it after every test.