salinity monitoring

padi200 · 07/16/2008, 10:19 AM

I wonder if someone can tell me about the pros and cons of using a salinity monitor such as PINPOINT Salinity Monitor from American Marine, vs a hydrometer and spot checking, or using a refractometer and also spot checking.

Thanks!

IslandCrow · 07/16/2008, 10:31 AM

Truthfully, I don't think it's really worth the expense, unless you're using it along with a controller to actually regulate your salinity. As long as you're topping off regularly with fresh water, your salinity should not change significantly in the near to mid term. I check my salinity with a refractometer once a week, and it's very rare that it's anything other than 35ppt. Speaking of which, I'd recommend a refractometer over a hydrometer. The bulb style hydrometers are pretty decent, but those swing arm hydrometers are fairly unreliable. No matter what you use, just make sure you calibrate it.

padi200 · 07/16/2008, 10:34 AM

Thanks, sadly I have the corallife deep six with the swing arm now.

That is why i want to find a better way!

Randy Holmes-Farley · 07/16/2008, 10:35 AM

FWIW, the salinity monitor is a fine way to go, but it is best suited for spot checking too. I would not leave it in the tank water 24/7, since deposits or air bubbles will decrease the measured value.

I'd suggest either a glass floating hydrometer (like the Tropic Marin), a good refractometer calibrated with a seawater standard, or a conductivity meter, also calibrated (or at least checked for accuracy). I've used all of them, and the refractometer and the meter are the easiest. I'd avoid swing arm hydrometers.

I discuss these here:

The â€œHow Toâ€ Guide to Reef Aquarium Chemistry for Beginners, Part 1: The Salt Water Itself
http://reefkeeping.com/issues/2007-03/rhf/index.php

Refractometers and Salinity Measurement
http://reefkeeping.com/issues/2006-12/rhf/index.php

Temperature Corrections for Hydrometers
http://reefkeeping.com/issues/2004-07/rhf/index.htm

Reef Aquarium Salinity: Homemade Calibration Standards
http://reefkeeping.com/issues/2004-06/rhf/index.htm

Specific Gravity Measurement
http://www.advancedaquarist.com/2002/1/chemistry

Using Conductivity to Measure Salinity
http://www.aquariumfish.com/aquarium....aspx?aid=1804

chelbuznoz · 07/16/2008, 10:38 AM

I have never had a problem with only checking salinity once a week. Some people don't even do it that often. I use a refractometer from day one. I think as long as you know that whatever you are using is calibrated correctly, once a week is fine.

Randy Holmes-Farley · 07/16/2008, 10:44 AM

The one thing that a salinity/conductivity meter is especially useful for is equilibration, where you can get continuous readings on salinity (and sometimes also temperature) as you bring tank water into a shipping bag.

It can also be used to measure limewater potency, which a refractometer may not be especially suited for.

padi200 · 07/16/2008, 10:57 AM

the American Marine salinity monitor is about $130 and the Milwaukee Refractometer is about $90. My top off system adds about a gallon a day. So if I am going to spot check, say every few days, which of those two woud you pick?

Randy Holmes-Farley · 07/16/2008, 11:05 AM

Either will be perfectly adequate.

I use a conductivity meter (expensive and not currently sold new)that is similar to, but somewhat faster to respond to temperature changes than is the Pinpoint.

Randy Holmes-Farley · 07/16/2008, 11:08 AM

Oh, and noting your profession, don't try using a clinical refractometer. Despite its possibly having markings in ppt or specific gravity, it is not suitable for seawater salinity as opposed to its intended use of proteins in urine and serum and such.

padi200 · 07/16/2008, 11:16 AM

Thanks for all the informatin. I was thinking about using
Clinical Refractometer. I have and old one that I used to use for unine testing. I WILL NOT USE IT, but I thought about it and thanks for the proactive advice.

I think I will go with the monitor. It seems easy to use and I will use it for spot checks not continuous monitoring.

Now on to my next problem, my high alkalinity with my Ca reactor.
I will post that on a new thread.

THANKS AGAIN!

Randy Holmes-Farley · 07/16/2008, 12:31 PM

Happy Reefing.

padi200 · 07/16/2008, 09:59 PM

ps just curious, what did you discover at Genzyme?

Randy Holmes-Farley · 07/17/2008, 04:48 AM

Renagel and Renvela sold as oral phosphate binders for renal disease patients,

www.renagel.com
www.renvela.com

and WelChol (Cholestagel in Europe) sold as an LDL cholesterol lowering agent and now also marketed by Sankyo for diabetes.

http://www.welchol.com/
www.cholestagel.com

Others are still in clinical or preclinical testing.

07/16/2008, 10:19 AM	#1
padi200 Registered Member Join Date: Feb 2006 Location: LA, CA Posts: 529	salinity monitoring I wonder if someone can tell me about the pros and cons of using a salinity monitor such as PINPOINT Salinity Monitor from American Marine, vs a hydrometer and spot checking, or using a refractometer and also spot checking. Thanks!

07/16/2008, 10:31 AM	#2
IslandCrow Reef Monkey Join Date: Sep 2005 Location: Rockledge, Fl Posts: 5,759	Truthfully, I don't think it's really worth the expense, unless you're using it along with a controller to actually regulate your salinity. As long as you're topping off regularly with fresh water, your salinity should not change significantly in the near to mid term. I check my salinity with a refractometer once a week, and it's very rare that it's anything other than 35ppt. Speaking of which, I'd recommend a refractometer over a hydrometer. The bulb style hydrometers are pretty decent, but those swing arm hydrometers are fairly unreliable. No matter what you use, just make sure you calibrate it. __________________ All opinions in the above message should be taken with 35 ppt salt. -Mike C. Current Tank Info: I have a reef screen saver on my phone, does that count?

07/16/2008, 10:34 AM	#3
padi200 Registered Member Join Date: Feb 2006 Location: LA, CA Posts: 529	thanks! Thanks, sadly I have the corallife deep six with the swing arm now. That is why i want to find a better way!

07/16/2008, 10:35 AM	#4
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	FWIW, the salinity monitor is a fine way to go, but it is best suited for spot checking too. I would not leave it in the tank water 24/7, since deposits or air bubbles will decrease the measured value. I'd suggest either a glass floating hydrometer (like the Tropic Marin), a good refractometer calibrated with a seawater standard, or a conductivity meter, also calibrated (or at least checked for accuracy). I've used all of them, and the refractometer and the meter are the easiest. I'd avoid swing arm hydrometers. I discuss these here: The â€œHow Toâ€ Guide to Reef Aquarium Chemistry for Beginners, Part 1: The Salt Water Itself http://reefkeeping.com/issues/2007-03/rhf/index.php Refractometers and Salinity Measurement http://reefkeeping.com/issues/2006-12/rhf/index.php Temperature Corrections for Hydrometers http://reefkeeping.com/issues/2004-07/rhf/index.htm Reef Aquarium Salinity: Homemade Calibration Standards http://reefkeeping.com/issues/2004-06/rhf/index.htm Specific Gravity Measurement http://www.advancedaquarist.com/2002/1/chemistry Using Conductivity to Measure Salinity http://www.aquariumfish.com/aquarium....aspx?aid=1804 __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

07/16/2008, 10:44 AM	#6
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	The one thing that a salinity/conductivity meter is especially useful for is equilibration, where you can get continuous readings on salinity (and sometimes also temperature) as you bring tank water into a shipping bag. It can also be used to measure limewater potency, which a refractometer may not be especially suited for. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

07/16/2008, 10:38 AM	#5
chelbuznoz Registered Member Join Date: Mar 2008 Location: Chelsea, MI Posts: 5	I have never had a problem with only checking salinity once a week. Some people don't even do it that often. I use a refractometer from day one. I think as long as you know that whatever you are using is calibrated correctly, once a week is fine.

07/16/2008, 10:57 AM	#7
padi200 Registered Member Join Date: Feb 2006 Location: LA, CA Posts: 529	the American Marine salinity monitor is about $130 and the Milwaukee Refractometer is about $90. My top off system adds about a gallon a day. So if I am going to spot check, say every few days, which of those two woud you pick?

07/16/2008, 11:05 AM	#8
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Either will be perfectly adequate. I use a conductivity meter (expensive and not currently sold new)that is similar to, but somewhat faster to respond to temperature changes than is the Pinpoint. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

07/16/2008, 11:08 AM	#9
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Oh, and noting your profession, don't try using a clinical refractometer. Despite its possibly having markings in ppt or specific gravity, it is not suitable for seawater salinity as opposed to its intended use of proteins in urine and serum and such. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

07/16/2008, 11:16 AM	#10
padi200 Registered Member Join Date: Feb 2006 Location: LA, CA Posts: 529	Thanks! Thanks for all the informatin. I was thinking about using Clinical Refractometer. I have and old one that I used to use for unine testing. I WILL NOT USE IT, but I thought about it and thanks for the proactive advice. I think I will go with the monitor. It seems easy to use and I will use it for spot checks not continuous monitoring. Now on to my next problem, my high alkalinity with my Ca reactor. I will post that on a new thread. THANKS AGAIN!

07/16/2008, 12:31 PM	#11
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Happy Reefing. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

07/16/2008, 09:59 PM	#12
padi200 Registered Member Join Date: Feb 2006 Location: LA, CA Posts: 529	ps just curious ps just curious, what did you discover at Genzyme?

07/17/2008, 04:48 AM	#13
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Renagel and Renvela sold as oral phosphate binders for renal disease patients, www.renagel.com www.renvela.com and WelChol (Cholestagel in Europe) sold as an LDL cholesterol lowering agent and now also marketed by Sankyo for diabetes. http://www.welchol.com/ www.cholestagel.com Others are still in clinical or preclinical testing. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef