Hydrometers -- Which do you trust?

RobG · 11-10-2001, 06:54 PM

I've always had a coralife deep six hydrometer. I keep my tank at 1.025-1.026 at 77-80 degrees. Well, the hydrometer got a little dirty, so I picked up a new one: A SeaTest hydrometer. Unfortunately for me, that hydrometer say my SG is 1.030!!!

That's way too high!

Which should I believe? (I know, I know, I should go buy a refractometer)

do I need to get a third opinion?

**Ninong** · 11-10-2001, 07:04 PM

You need a third opinion. See if your LFS has a refractometer that they could use to check your water for you.

Ninong

Ironreef · 11-10-2001, 07:06 PM

trust none only refractor IME

**golfish** · 11-10-2001, 10:17 PM

Yeah, using the plastic swing are hydrometer is a real pain and you could be asking for trouble. I have seen 6 of them filled at a LFS and they all had very different readings. I have use one of those very LARGE floating hydrometers (I think its a Tropic Marine) They are very good but hard to use because there so big. The refractometer is probably the easies and best way to go.

Mark

cod · 11-11-2001, 05:50 PM

I use the floating type. They are much easier to work with in a graduated cylinder or some similar container.

fishpoo · 11-11-2001, 07:27 PM

i use an old seatest and really trust it. i make sure my tank water and water ready for change have the same reading. that's accurate enough for me. i've done it that way for years without any problems in salinity.

Iron Crab · 11-11-2001, 07:43 PM

I have an old Seatest that hasn't fail me yet. I do what Ninong suggests- every once in a while I take it to one of my LFS's and have it check out. So far it has been true.

Ironreef · 11-11-2001, 08:09 PM

I have 2 hydrometer one is .02 off the other is .o4 off. I would calibrate it with a refractor so you have an idea of where its at. I thought i was keeping my salinity at 1.023-4 But I noticed my tang was getting a sore. Could fiqure what it was then I get the salinity with my refractor. Something i haven't done for awhile. It was 1.030. I slowely reduced it to a 1.022 and the sore went away in a few days. The fish may have reacted to the salinity?? Whatever I would just get my hydrometer calibrated to you have a true range.

MarkS · 11-11-2001, 08:27 PM

I have only used the floating type. They are supposed to be the most accurate just behind a refractometer. I bought a really big one and have had trouble getting readings since I only have nano tanks. What I did was to get a 12" long, 1 1/4" ID acrylic tube and glued it to a 1/4" acrylic base. I just put the hydrometer in the tube and fill it with water. Works great!

Mark

mastaJ · 11-11-2001, 10:40 PM

I soak my "plastic swing-arm" hydroms in SW for about a week before I use them. They seem to be more acurate that way. HTH...

Ironreef · 11-12-2001, 12:20 AM

I would think you would keep them clean not soak them in SW? This just shows how not to trust them. They are good you just need to calibrate them so you accually know what it is

RobG · 11-12-2001, 02:04 PM

Just ordered a refractometer from NorthCoast Marines. That will solve my problem.

I've spent way too much money on critters, corals and fish to mess around with a $12.00 hydrometer anymore. So, I'll know which one should have been trusted soon enough...

Thanks for the replies!

Rob

**golfish** · 11-12-2001, 05:50 PM

Very good choice Rob....

mastaJ · 11-12-2001, 11:28 PM

Quote:

Originally posted by Ironreef
I would think you would keep them clean not soak them in SW? This just shows how not to trust them. They are good you just need to calibrate them so you accually know what it is

Clarification: I soak BRAND-NEW hydrometers in SW for about a week. For me when I open a new hydro I'll measure SW about ten times and get about ten different answers with a new hydrometer. However, on a different hydrometer I soaked it in SW for roughly a week and it gave the same result consistently. Refractometer sounds like it would be the best choice, needless to say, I will be getting one soon

11-10-2001, 06:54 PM	#1
RobG Council Join Date: Apr 2001 Location: Cleveland, Ohio Posts: 288	Hydrometers -- Which do you trust? I've always had a coralife deep six hydrometer. I keep my tank at 1.025-1.026 at 77-80 degrees. Well, the hydrometer got a little dirty, so I picked up a new one: A SeaTest hydrometer. Unfortunately for me, that hydrometer say my SG is 1.030!!! That's way too high! Which should I believe? (I know, I know, I should go buy a refractometer) do I need to get a third opinion?

11-11-2001, 05:50 PM	#5
cod Tenant Join Date: May 2001 Location: china grove,n.c. usa Posts: 75	I use the floating type. They are much easier to work with in a graduated cylinder or some similar container. __________________ It's more a science project than a fish tank

11-11-2001, 07:27 PM	#6
fishpoo Citizen Join Date: Jul 2000 Location: north bergen, nj, usa Posts: 174	i use an old seatest and really trust it. i make sure my tank water and water ready for change have the same reading. that's accurate enough for me. i've done it that way for years without any problems in salinity. __________________ great post! bring this one up to the top.

11-11-2001, 08:27 PM	#9
MarkS Governor Join Date: Jun 2000 Location: San Antonio, Tx Posts: 1,799	I have only used the floating type. They are supposed to be the most accurate just behind a refractometer. I bought a really big one and have had trouble getting readings since I only have nano tanks. What I did was to get a 12" long, 1 1/4" ID acrylic tube and glued it to a 1/4" acrylic base. I just put the hydrometer in the tube and fill it with water. Works great! Mark __________________ 2 + 2 != 4 Two is only loosely associated with two by a plus sign and therefore doesn't enter the equation at all since it is only there by mere complicity. We shouldn't count it and leave well enough alone.

11-11-2001, 10:40 PM	#10
mastaJ Council Join Date: May 2001 Location: Lakeville, MN Posts: 294	I soak my "plastic swing-arm" hydroms in SW for about a week before I use them. They seem to be more acurate that way. HTH... __________________ -mastaJ

11-10-2001, 07:04 PM	#2
Ninong Moderator Join Date: Jun 2000 Location: Louisiana Posts: 20,330	You need a third opinion. See if your LFS has a refractometer that they could use to check your water for you. Ninong

11-10-2001, 07:06 PM	#3
Ironreef Governor Join Date: Aug 2000 Location: Pacific WA Posts: 1,220	trust none only refractor IME

11-10-2001, 10:17 PM	#4
golfish Moderator Join Date: Jun 2000 Location: Alta Loma,Ca Posts: 2,943	Yeah, using the plastic swing are hydrometer is a real pain and you could be asking for trouble. I have seen 6 of them filled at a LFS and they all had very different readings. I have use one of those very LARGE floating hydrometers (I think its a Tropic Marine) They are very good but hard to use because there so big. The refractometer is probably the easies and best way to go. Mark

11-11-2001, 07:43 PM	#7
Iron Crab Council Join Date: Mar 2000 Location: N.W. Pennsylvania, USA Posts: 434	I have an old Seatest that hasn't fail me yet. I do what Ninong suggests- every once in a while I take it to one of my LFS's and have it check out. So far it has been true.

11-11-2001, 08:09 PM	#8
Ironreef Governor Join Date: Aug 2000 Location: Pacific WA Posts: 1,220	I have 2 hydrometer one is .02 off the other is .o4 off. I would calibrate it with a refractor so you have an idea of where its at. I thought i was keeping my salinity at 1.023-4 But I noticed my tang was getting a sore. Could fiqure what it was then I get the salinity with my refractor. Something i haven't done for awhile. It was 1.030. I slowely reduced it to a 1.022 and the sore went away in a few days. The fish may have reacted to the salinity?? Whatever I would just get my hydrometer calibrated to you have a true range.

11-12-2001, 12:20 AM	#11
Ironreef Governor Join Date: Aug 2000 Location: Pacific WA Posts: 1,220	I would think you would keep them clean not soak them in SW? This just shows how not to trust them. They are good you just need to calibrate them so you accually know what it is

11-12-2001, 02:04 PM	#12
RobG Council Join Date: Apr 2001 Location: Cleveland, Ohio Posts: 288	Just ordered a refractometer from NorthCoast Marines. That will solve my problem. I've spent way too much money on critters, corals and fish to mess around with a $12.00 hydrometer anymore. So, I'll know which one should have been trusted soon enough... Thanks for the replies! Rob

11-12-2001, 05:50 PM	#13
golfish Moderator Join Date: Jun 2000 Location: Alta Loma,Ca Posts: 2,943	Very good choice Rob....

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