so i recieved my newest toy a vertex refractometer. calibrated it with bought di water and was amazed what i found. when id check the salinity with my hydrometer it would read 35ppt or 1.025. now when i check with refractometer it measured a lil over 40ppt now correct me if im wrong thats a big difference. so a big thank you to mojoreef for telling me hydrometers suck and i need a refractometer. so far best purchase yet. ive slowly been lowering the salinity in my tanks and guess what. my leathers are dooing much better all polyps are fully open tank couldant be happier. so for all of u useing a hydrometer throw it against the wall and get a refractometer.
refractometer vs hydrometer proven results
- Thread starter senji
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BigAl07
Well-known member
Outstanding! Thanks for posting the results!!
Now keep in mind we need to differentiate between your "Swing Arm" hydrometer and a "Floating Tube" hydrometer. The later being extremely accurate and often times considered about as accurate as you can get without going true "lab grade" equipment.
I have to agree that getting a good quality refractometer is probably some of the best money you can spend on your tank. It's super accurate and super EASY! That's a WIN-WIN any day of the week.
Now keep in mind we need to differentiate between your "Swing Arm" hydrometer and a "Floating Tube" hydrometer. The later being extremely accurate and often times considered about as accurate as you can get without going true "lab grade" equipment.
I have to agree that getting a good quality refractometer is probably some of the best money you can spend on your tank. It's super accurate and super EASY! That's a WIN-WIN any day of the week.
Raamiah
Well-known member
Yeah I tested the difference between my hydrometer and refractometer the other day to see if I could keep one at home and the other at work but I don't think I can trust it to be constant either so I'm going to buy one so I have one at home and the office so I always know the SG. My refractometer read 1.023 and my hydrometer said 1.020. It's really not good to have those so far off.
Definitely!
A good, 12" floating hydrometer is about the best the home hobiest can get, but they are enough of a pain to use (plus, if you are like me, you end up doing something dumb and breaking one every few years) that a refractometer ends up being a win-win compromise.
Just be aware that things like organice can affect refractomer readings a bit.
1guydude
Well-known member
i dont even wait.... i read it when its on my vertex. Beware though that u need to check the calib. on the vertex every now and again. I believe its best to keep it at the same temp as ur tank room temp imoe.
NC2WA
Well-known member
another good purchase is a RO DI unit to make your own water, along with a TDS meter (if you dont already have one)
rayjay
Well-known member
If you have a standard salinity refractometer then calibration with water will give you erroneous readings at normal salinity of reef tanks.
Even if you have one of the few sea water refractometers, it's still wise to use calibration fluid instead of water.
http://reefkeeping.com/issues/2006-12/rhf/index.php
MGDMIRAGE
Shoulda been a fish!
Never calibrate refractometer with DI water, your hydrometer may be more accurate. Get the proper calibration solution and calibrate it!
ok just to proove a point i ran a few tests on the di water used to cal . density 0.972, viscosity 3.55 x 10 -4th, kimatic 3.65 x 10 -7th, surface tension 6.26 x 10 -2nd, bulk modulus 2.20, thermal expansion coeficient 6.41 x 10 -4. im a hydroponics teacer at a local colledge and have acces to the best equipment and boy do i know water.will get ur calibration soulution and post tests of it. i hypothisise it will be the same.its just sealed di in a packet to ensure no contamination.
rayjay
Well-known member
Do the instructions also tell you that doing calibration that way, it will only be accurate if you are testing NaCl in water? (unless it specifically states that it is a seawater refractometer but there aren't too many of those in the hands of hobbyists yet)
Did you read that article by Randy Holmes-Farley? Everything is explained there.
Unfortunately being an expert on water doesn't make anyone an expert on refractometers, so Randy has written the article to help clear things up to those of us who don't have full comprehension of the workings of a refractometer.
IMO, Randy has helped the hobby tremendously with the articles he has authored and for the answers he provides on RC Reef Chemistry Forum. (he is a chemistry scientist who happens to be a reefer)
His page of links can be found here. http://archive.reefcentral.com/forums/showthread.php?s=&threadid=102605
rayjay
Well-known member
I forgot to mention, that even doing everything with calibration fluids, you are open to error because the standards also lack credibility somewhat.
Randy did testing of many brands of calibration fluids and found variation. Now the amount of variation isn't real critical to us as hobbyists, but nevertheless it still exists.
If I want a true, exact reading, I use my Fisher Scientific certified calibrated hydrometer in the proper cylinder and it doesn't lie.
Randy did testing of many brands of calibration fluids and found variation. Now the amount of variation isn't real critical to us as hobbyists, but nevertheless it still exists.
If I want a true, exact reading, I use my Fisher Scientific certified calibrated hydrometer in the proper cylinder and it doesn't lie.
Krish
RF STAFF
I like the taste test best. Finger in the tank then in your mouth and guess salinity. Spot on every time! eace:
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eace:Sent from my iPhone using Tapatalk
Yes, but your life down there in paradise has calibrated you.I like the taste test best. Finger in the tank then in your mouth and guess salinity. Spot on every time!
Krish
RF STAFF
Lol! True! It's either salty, too salty or needs salt.
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but if you dare say that it needs spice, I'll tell your wife on you!Lol! True! It's either salty, too salty or needs salt.
