Adjusting salt mixing for temperature variations

[larrysaltisfun]

I am in the process of installing an RODI system with mixing station.

One room I have available is literally an outdoor shower, which is an ideal location based on the location of my tanks, which are directly above

One issue that I thought about was …..since this room is not heated and cooled (although I have potential to add heat at additional cost ) it could make salt mixing a mathematical challenge since specific gravity is a function of temperature. I’m envisioning that in the winter time temperature swings could be anywhere from 40° to 60°.(ambient temperature ) and In the summertime as high as upper 80s when making salt water

I know conversion calculators are available and I will need to shoot for lower specific gravity in cold weather and a higher specific gravity in warm weather in order to shoot for 1.025 to 1.026 in my display tank.

I do have a room available in the house for potential mixing station which is at a more consistent temperature, , but the routing to the tank is much more circuitous.

So in trying to adhere to the KISS principal, will there be a significant difference in the amount of salt needed to hit an appropriate specific gravity designed for 1.025 to 1.026 at 78° when I am mixing the salt at anywhere between 40 and 80° ….And does anyone have a rough idea per 5 gallons or 20 gallons or any other measure how much additional salt would be needed in colder temperatures versus warmer temperatures?

I was assuming that I would use a tropic Marin hydrometer , Would using an electronic tool that measures salinity make this easier?
Thank you

 

[Kooma]

This is an interesting topic and one I’d love to know more of. I always mark my tanks and fill to that line, add my salt, heat it and check the levels. For me, I have a mark that if I add 15 cups of salt I get 1.026 every time. I expect that your volume to salt needed won’t change based on the temp, as you’ll need to heat it before use anyways in most cases.

 

[KStatefan]

Temperature does not change salinity so it will take the same amount of salt. My mixing is in a heated garage but if I just made water in the winter it can still be fairly cold low sixties when I mix

 

[Randy Holmes-Farley]

As noted, salinity does not ever change at all with temperature, and specific gravity hardly changes at all. What can change substantially are the readings one gets from uncorrected devices used for measurement, especially floating glass hydrometers.

Most refractometers and all normal conductivity meters will temperature correct unless you turn off that feature.

 

[Sisterlimonpot]

Most refractometers and all normal conductivity meters will temperature correct unless you turn off that feature.

This is what i came here to say as well.

Using the KISS method is using a hobby grade refractometer and keep it calibrated. The ATC (automatic temp compensation) that you see on most refractometers does the heavy lifting for you.

 

[slingfox]

I mix my latter in 50 gallon barrels in the garage. Temperature various from 30 degrees to 95 degrees. I use high quality refractometer with ATC. I haven’t had any major issues with salinity since I got a new refractometer.

 

[Randy Holmes-Farley]

I make new salt water, test my tank water, and store my salinity standard in my basement where it can be very cool. When I move my conductivity meter from the cold standard to the warm tank water, I can watch the reading drop as the device sensor comes up in temperature over a few minutes and applies more and more correction to give an accurate reading.

 

[larrysaltisfun]

I make new salt water, test my tank water, and store my salinity standard in my basement where it can be very cool. When I move my conductivity meter from the cold standard to the warm tank water, I can watch the reading drop as the device sensor comes up in temperature over a few minutes and applies more and more correction to give an accurate reading.

Ok so the comments that the Tropic Marine hydrometer are the most accurate measuring tool only holds for 77-78 degrees ?

 

[larrysaltisfun]

I mix my latter in 50 gallon barrels in the garage. Temperature various from 30 degrees to 95 degrees. I use high quality refractometer with ATC. I haven’t had any major issues with salinity since I got a new refractometer.

What refractometer do you use?

 

[slingfox]

What refractometer do you use?

The VeeGee Stx-3. It is not cheap but very reliable. I purchased it 25 months ago and have not had to adjust the calibration (I check every six months or so).

The salinity lines up nearly perfectly with my last ICP from ATI:

 

[larrysaltisfun]

What refractometer do you use?

The VeeGee Stx-3. It is not cheap but very reliable. I purchased it 25 months ago and have not had to adjust the calibration (I check every six months or so).

The salinity lines up nearly perfectly with my last ICP from ATI:

Thank you!

 

[Sisterlimonpot]

Ok so the comments that the Tropic Marine hydrometer are the most accurate measuring tool only holds for 77-78 degrees ?

It's always wise to be skeptical of claims provided by a company that wants to sell you something.

I read that the tropic marin hydrometer is the gold standard, and how it's touted to be the hobbyist #1 go to for accuracy. I find that to be marketing. I've been in this hobby a very long time and have an active community of local hobbyist and I can't think of one person who uses one of those. The trusted refractometer seems to be the most common.

I personally use the hanna salinity tester. It does require calibration, but most of the time I only use it to see what my tank salinity is and I mix salt to that. Regardless of how accurate the reading is, I know that my new salt is mixing to the tank. Then, every few months I will calibrate and check tank salinity.

 

[slingfox]

It's always wise to be skeptical of claims provided by a company that wants to sell you something.

I read that the tropic marin hydrometer is the gold standard, and how it's touted to be the hobbyist #1 go to for accuracy. I find that to be marketing. I've been in this hobby a very long time and have an active community of local hobbyist and I can't think of one person who uses one of those. The trusted refractometer seems to be the most common.

I personally use the hanna salinity tester. It does require calibration, but most of the time I only use it to see what my tank salinity is and I mix salt to that. Regardless of how accurate the reading is, I know that my new salt is mixing to the tank. Then, every few months I will calibrate and check tank salinity.

Unfortunately the Hanna Salinity meter is not reliable. I have been through 3 of them and testing them against other instruments, ICP and the Randy-Holmes Farley DIY calibration solution and could not get consistent readings. I even tested pairs of Hanna salinity meters (I did this test with two different sets) and they could not agree with each other even when calibrated immediately before! I went through half a dozen or so of the Hanna calibration packets. I still have one of the Hanna salinity meters sitting around but never use it due to its unreliability.

 

[larrysaltisfun]

Ok so the comments that the Tropic Marine hydrometer are the most accurate measuring tool only holds for 77-78 degrees ?

It's always wise to be skeptical of claims provided by a company that wants to sell you something.

I read that the tropic marin hydrometer is the gold standard, and how it's touted to be the hobbyist #1 go to for accuracy. I find that to be marketing. I've been in this hobby a very long time and have an active community of local hobbyist and I can't think of one person who uses one of those. The trusted refractometer seems to be the most common.

I personally use the hanna salinity tester. It does require calibration, but most of the time I only use it to see what my tank salinity is and I mix salt to that. Regardless of how accurate the reading is, I know that my new salt is mixing to the tank. Then, every few months I will calibrate and check tank salinity.

Thank you for your time.

I have an old refractometer from Marine depot about 12 years old. That consistently reads 1.024 while my tropic marin hydrometer reads 1.026( which also is what my LFS gets) . I just couldn’t see carrying this hydrometer out side every time I needed to make salt no matter how good it is . It is so fragile I’m sure I would break it in about two or three days. Plus, as you can see from my first post I knew that the hydrometer reading would definitely be altered by abnormally cold temperatures. I just didn’t know that no adjustment would be necessary in the salt mix

Going to take sling foxes advice, and get the Vee Gee stx 3

 

[larrysaltisfun]

As noted, salinity does not ever change at all with temperature, and specific gravity hardly changes at all. What can change substantially are the readings one gets from uncorrected devices used for measurement, especially floating glass hydrometers.

Most refractometers and all normal conductivity meters will temperature correct unless you turn off that feature.

Thank you, Randy for a very concise explanation pinpointing where my logic was illogical , and it was more than just a few “ significant figures “ lol

 

[BeanAnimal]

I can't think of one person who uses one of those. The trusted refractometer seems to be the most common.

I even built a temperature compensation calculator

Tropic Marin Precision Hydrometer Correction Calculator | BeanAnimal's Reef

Use this simple calculator to temperature correct your Tropic Marin Precision Floating Hydrometer readings and never guess about your aquarium salinity again!

beananimal.com

 

[BeanAnimal]

I use it as my standard to calibrate my GHL conductivity probe and 2 cheap refractometers.

When they don’t match each other, I reset them to the TM.

 

[Randy Holmes-Farley]

Ok so the comments that the Tropic Marine hydrometer are the most accurate measuring tool only holds for 77-78 degrees ?

It NEVER hold as written (high quality conductivity meters are clearly better, but expensive), but its a perfectly fine tool at any temperature if you correct it with an appropriate table.

 

[KStatefan]

Ok so the comments that the Tropic Marine hydrometer are the most accurate measuring tool only holds for 77-78 degrees ?

It is not hard to convert with calculator or chart.

 

[Ef4life]

A great way to kill stuff in your tank is to pump in 40* water during a waterchange

Just add a heater to the water bin, use a smart plug to schedule the heater to operate a few hrs before waterchanges.