Refractometer or hydrometer

[edm005]

I am fairly new to saltwater. I purchased a cheap Odysea hydrometer and it seemed to work fine. In reading different opinions I decided to get a refractometer because of higher accuracy. Well, I bought the cheap $24 one off the internet and not sure that was the way to go. I have calibrated it with DI/RO water and when I test my tank water it reads 1.024. The problem is that the hydrometer reads 1.020. Which one would you think to be correct?

 

[turningtim]

I would easily trust the refracto over the hydro. But I also would use distilled water for calibration.
Just boil some water and hold a clean plastic cup over the steam. Once you get a collection of droplets in the cup let it sit a cool for a bit and use that to calibrate your refractometer.
But your are not going to get a better reading from a hydro. This is not the first time that a hydro has been off by that much!
HTH
Tim

 

[gmann1139]

Ditto on the refract.
Swing arm or floating btw?
Here's an easy test of which one's accurate. Assuming your water has a constant salinity/sg, sample it 3 or 4 times each with both the refractometer and the hydrometer.
You'll see a range of results for the hydrometer, but the refractometer should be pretty dead-on each time.

 

[perfectdark]

I agree... trust the refractometer readings over the hydrometer. You can also purchase calibration fluid. My refratc came with some so if there is ever a question thats my go to stuff.
For the best results you can get look into a lab grade hydrometer. They are not cheap but there is no better instrument for measuring S.G.

 

[edm005]

The hydro is a swing arm and ussually testes the same each time. The refracto doesn't vary at all. When I first started using it, I thought it was because I forgot to rinse out my dropper in between test (which I do now). The reason I ask is that my 2 week old clown died this morning and I am trying to find out why. I did notice a 1.5 degree temp drop. What do you think?

 

[turningtim]

It could be unrelated to the SG. What are the rest of your parmeters? How fast did the temp drop and what is it now? But I wouldn't think that 1.5 degrees would cause that much harm. Anything else in the tank acting strange? Is there another critter being aggressive? Could have been the fish.......

 

[perfectdark]

Originally Posted by edm005
http:///forum/post/2570802
The hydro is a swing arm and ussually testes the same each time. The refracto doesn't vary at all. When I first started using it, I thought it was because I forgot to rinse out my dropper in between test (which I do now). The reason I ask is that my 2 week old clown died this morning and I am trying to find out why. I did notice a 1.5 degree temp drop. What do you think?
I doubt salinity had anything to do with it. If it was alive for 2 weeks and suddenly died your salinity would of had to change drastically in the last 24 hours to stress and possibly kill your fish. Other wise common hyposalinity treatment for ich is a drop from 1.025 to 1.009 in 48 hours and most fish live through that with no problems. I would look else where for your issue. How is your water testing. Amonia, trites, trates, pH, alk and tank temp. Also how new is your tank and what else is in it? These things may help you find out why your fish died or may not. Good Luck.
To help with your answer, what is needed is specific readings from good liquid test kits not strips or your LFS telling you everything is fine. A lot of times what they consider to be fine isnt and can be linked to what is happening to your fish.

 

[edm005]

Started 55 gal. tank 2/1/08. Let water settle and added 80 lbs live rock to empty tank to cure on 2/15/08. Added sand on 2/21/08 and did a water change. All this time, removing rock and cleaning it. On 2/26/08 did water hange and then added 27.5 ml Colonize additive. All this time parameters looked good using API liquid test kit. Added first fish (clown) on 4/8/08 and 2 hermits.
It should have had plenty of time to cycle, right? I added colonize 3 times to tank like recommended and have been doing water changes.
Clown lasted 10 days.
Current parameters:
SG 1.024
PH 8.4
Temp 75.2
Alk 300 KH
Ammonia, nitrite, nitrate 0

 

[edm005]

Also the clown never wanted to eat. I tried flake and seaweed on a clip. He acted OK (i.e. swimming around in his home area) but just didn't want to eat. Sometimes he would try to eat but just spit it back out. He looked OK. I am confused.

 

[turningtim]

Temp is low, try a bring it up to 78-80 gradually. Also would try and feed some frozen Mysis shrimp. You can also add some garlic to get fish to eat.
How did you acclimate the fish? Sounds to me like he/she was off on a bad start to begin with. Do you know if it was eating at the LFS and how long it had been there before you got it?

 

[alexmir]

Did you get the clown shipped to you? or get it from a LFS. even if you got it from the store, i have had two clowns shipped to me in the past and both of them died. I have read that they are not very good shippers. Also, neither one of them would eat very well. I decided to try a clown one more time and made the guy at the LFS feed it so i could see him eat, and then quarantined him for 2 1/2 weeks. Hes doing wonderful now!

 

[edm005]

I did a drip method acclimation-just like is recommened over about an hour and a half. I never did see him eat at the LFS.
Would there ever be a time when you buy a clown out of a tank that has 6 or more in it that maybe he was paired up with another and does that make a difference if you seperate them?

 

[perfectdark]

No it doesnt, but what does matter is how long it was at your LFS for. Was this a new shipment, days or hours old? FWIW, When fish are captured in the wild they shut down all non-essential processes such as digestion and the immune system for immediate use of energy for the purpose of escape. And no fish, no matter how well cared for from time of capture to arrival at your doorstep are as good as they were in the wild. They are stressed, usually starved, and have been held captive in many different and questionable water conditions of which none come near the pristine quality of their natural surroundings.
If your tank was healthy, water quality was good, I too believe this was most likley a very unhealthy fish from the get go.