Out with the trash!

[Monte26]

So, I'm not new to the hobby, but figured the newer people should read this. Tonight I've officially thrown out my swing arm hydrometer! I've been using my refractometer for about 6 months now, but have been in the hobby for 5+ years. I cannot believe I've been trusting my hydrometer for all these years. We put so much money, time, and effort into this! I urge everyone in the hobby to spend the $30 on a refractometer and please, for the love of God, use calibration fluid! Lol. End of my PSA :P

[kgeig001]

Was it off bad?

[GimpyFin]

One of the first things I replaced. I think I used a swing arm only a few times before chucking it. I bought a milwaukee digital refractometer and it's amazing. They only need ro/di or distilled water for calibration.

[Monte26]

It was off by .001, so not too bad, but I keep my reef at 1.026. My water was actually 1.027 which is too high for my liking

[roosterchef]

gimpyfin, how long have you had yours? Was looking to buy one but read a couple reviews complaining about not lasting well and breaking down. Thx.

[heathlindner25]

Congratulations on the Discovery

[Fish doctor]

Yes I agree with you. When I got one a few months ago. I had to smile at how much better it worked. As well as the confidence it gave me.

[BeachVacationer]

I just ordered one today. My lps and soft corals were not happy for the last 3 weeks. I bought stuff from refers recently and their water tested low with my swing arm. So I brought my water to a reef store and they measured it to be 1.028 where as the swing are showed 1.023. Way off right? My hydrometer is almost a year old. No wonder my corals are ****ed off. Hoping they come back ok. Anxiously awaiting arrival of my refractometer.

[Bent]

I disagree with using one point of testing.

[Ron Reefman]

Originally Posted by BeachVacationer

I just ordered one today. My lps and soft corals were not happy for the last 3 weeks. I bought stuff from refers recently and their water tested low with my swing arm. So I brought my water to a reef store and they measured it to be 1.028 where as the swing are showed 1.023. Way off right? My hydrometer is almost a year old. No wonder my corals are ****ed off. Hoping they come back ok. Anxiously awaiting arrival of my refractometer.

If you think 0.005 difference in salinity is the cause for your corals being that upset, I have a bridge in Brooklyn I'd like to sell you!

And I agree with Ben. Comparing your meter to one other just says one of you is wrong (unless the LFS calibrated their meter right there in front of you).

And to the OP and all the others that have trashed the hydrometer, I'll give you a different take on the situation.

I use a hydrometer all the time. But one of the first things I did was take my refractometer and calibrated it with proper calibration fluid. Then I tested my aquarium water with both the refractometer and the hydrometer. The refractometer said 1.025 and the hydrometer said 1.021. So I made a label that says "add .004" and put it on the side of the hydrometer.

Over the past 5 years I've used the hydrometer almost exclusively. But every 3 months at first, and less and less frequently as time went by, I would pull out the refractometer, calibrate it and compare it to the hydrometer. Every single time I do the comparison the hydrometer reads 0.004 too low.

So refractometers, if calibrated can read exactly right, but how often do you need to calibrate it? I found mine needed it every 6 to 12 months when I used it regularly. But I only 'calibrated' my hydrometer once 5 years ago and it has been absolutely the same ever since.

So I'll keep my cheap hydrometer and do the simple math of adding 0.004 to whatever the meter says. Oh, and how much less expensive is the hydrometer compared to a refractometer?

[Xxero]

Originally Posted by Ron Reefman

Oh, and how much less expensive is the hydrometer compared to a refractometer?

About $22.

[Bent]

Originally Posted by Ron Reefman

If you think 0.005 difference in salinity is the cause for your corals being that upset, I have a bridge in Brooklyn I'd like to sell you!

And I agree with Ben. Comparing your meter to one other just says one of you is wrong (unless the LFS calibrated their meter right there in front of you).

And to the OP and all the others that have trashed the hydrometer, I'll give you a different take on the situation.

I use a hydrometer all the time. But one of the first things I did was take my refractometer and calibrated it with proper calibration fluid. Then I tested my aquarium water with both the refractometer and the hydrometer. The refractometer said 1.025 and the hydrometer said 1.021. So I made a label that says "add .004" and put it on the side of the hydrometer.

Over the past 5 years I've used the hydrometer almost exclusively. But every 3 months at first, and less and less frequently as time went by, I would pull out the refractometer, calibrate it and compare it to the hydrometer. Every single time I do the comparison the hydrometer reads 0.004 too low.

So refractometers, if calibrated can read exactly right, but how often do you need to calibrate it? I found mine needed it every 6 to 12 months when I used it regularly. But I only 'calibrated' my hydrometer once 5 years ago and it has been absolutely the same ever since.

So I'll keep my cheap hydrometer and do the simple math of adding 0.004 to whatever the meter says. Oh, and how much less expensive is the hydrometer compared to a refractometer?

X2. I have 4 that are all 20 years old and they may be off, but they are consistently off. It's close enough that I can quickly check, do some addition or subtraction, and call it good. These animals go through significant swings in the ocean.

But again, I rarely just use one point of testing. I'll often test all 4 hydros, a float, and my refract all on Sunday. Just to make sure what I'm getting is true or close to true. I don't think any of use will ever actually know exactly what the SG of our mix actually is within .001, which equates to less than 1 part per trillion. I just have a hard time believing our equipment is that accurate. Plus I am not convinced it needs to be.

[tzylak]

Mine has always been off .002 I am ok with that.
It is very consistent.
Neither batteries nor calibration required!
Consider KISS

[davehead86]

Im in the KISS boat here too. I have a refractometer, havent even gotten the thing out and calibrated yet.

The only thing with a swing arm is that I need to clean it with non salt water because sometimes it sticks between uses. Give it a good rinse and shake and its all good to go.

[Jah2707]

I agree that using both isn't a bad idea. I had a refractometer when I first got into the hobby about 10 years ago and it was quit hard to read. I would have to take the shade off of the coffee table lamp to see the line very well. The new one i got a few months ago is way way better.

[BrokenSpoke]

Originally Posted by Bent

I don't think any of use will ever actually know exactly what the SG of our mix actually is within .001, which equates to less than 1 part per trillion.

I believe .001 is 1 part per thousand, not trillion although trillion does sound a heck of a lot better

[cloak]

My $7.99 floating glass hydrometer has never steered me wrong. I'm shooting for 1.025, 1.026, but as long as I can line it up somewhere in the green area everybody is happy.

[BrokenSpoke]

I used to use the floating hydrometers, plenty accurate, but I kept breaking them so I went to a refractometer.

[GimpyFin]

Originally Posted by roosterchef

gimpyfin, how long have you had yours? Was looking to buy one but read a couple reviews complaining about not lasting well and breaking down. Thx.

I've had my milwaukee for almost 3 years. No issues.

[d0ughb0y]

The only true way to measure specific gravity is using hydrometer. Archimedes principle has stood the test of time. Any other way of measuring specific gravity is just an approximation. Not saying other methods cannot be accurate as well, but perhaps more idiot proof. Any incorrect measurement based on Archimedes principle is likely due to user error.

[johnike]

I have a swingarm calibrated to a refractometer.

[jstack]

Originally Posted by Bent

I disagree with using one point of testing.

This so much I use refract and calibration solution BUT i still double check against my hydro is been calibrated with my lfs refrato

[Bent]

Originally Posted by BrokenSpoke

I believe .001 is 1 part per thousand, not trillion although trillion does sound a heck of a lot better

yes you are correct, ppt is parts per thousand not trillion. I must have been having a mini-stroke when I wrote that.

[Ron Reefman]

Glad to read that many reefers still use hydrometers. I've been making the argument for them being consistent (not accurate unless you calibrate it... once) for a long time and always seemed like I was the lone hydrometer user left in the hobby!