Salinity issue - readings all over the place!

[SirRoadwolf]

Hey all!

Over the past week or so, I have been scratching my head over a salinity issue in my tank. The issue started when - I believe - some snails blocked my return feed and caused some tank water to overflow out of the top of the display tank shorting out one of the power supplies for a wavemaker, which almost caused a fire.
Long story short, I wasn't home at the time, but my SO was, and I guided her through some steps to shut the system down until I got home.

Now, even before this happened, I was getting different readings from all of my salinity measuring devices, but the ones I trusted the most were the electronic probe that monitors it constantly, and my hydrometer. The refractometer seemed off to me, and the float meter never worked well for me.

To make up for the freshwater that was fed into the sump when there was no return water coming in, I added some salt to try to balance it out - using the hydrometer and electronic probe as a reference.

But after several days the corals are still not coming back. So I took a water sample to the LFS, and he measured the salinity at 1.038! Of note, my hydrometer was measuring 1.020! The electronic probe was measuring 35 ppt.

So, with that 1.038 reading that he got from a scientific salinity measuring device, I calibrated my refractometer and the electronic probe to match at about 48 ppt?

I drained some water and added fresh RO/DI water slowly (about 25 gallons of fresh water added, in a 110ish gallon system), until both refractometer and the electronic probe read within normal readings (1.026 refract/35.6ppt electronic probe). But a brand new float meter I bought yesterday from the LFS is still off the charts (above 1.032), and my hydrometer float is reading 1.014!

I plan on letting it sit for a while, but I fear at this point the corals are probably dead. (fish seem fine)

I guess I am looking for advice on what the issue could be, and which measurement devices would you trust more?

 

[Randy Holmes-Farley]

I'd never rely on an LFS to measure saliniity if it was far off of my own devices.

My suggestion is to make or buy a new 35 ppt calibration solution appropriate to each of your device types and calibrate/check them for accuracy.

 

[SirRoadwolf]

In the LFS's defense, it is a salt water reefing speciality store. And the owner has been in the reefing hobby for 30+ years.

 

[proxy001]

in an emergency scenario , I personally would check my refractometer against RODI. That gives you a calibration point. Not perfect but close enough that you should be in the safe zone.

 

[Randy Holmes-Farley]

In the LFS's defense, it is a salt water reefing speciality store. And the owner has been in the reefing hobby for 30+ years.

They might be correct. And they might not. Maybe the battery was running low in their device that day, etc. Maybe an air bubble was stuck on the probe. Maybe someone misread the device.

Be careful to not trust your tank unnecessarily,. Even big name hobby specialty companies make serious chemistry errors in their claims and product designs.

You can be sure if you make or buy a suitable calibration solution. If you have a scale and table salt, here are some good recipes:

Reef Aquarium Salinity: Homemade Calibration Standards by Randy Holmes-Farley - Reefkeeping.com

 

[SirRoadwolf]

Good advice indeed. I shall do that tonight when I get home from work. But I still wonder, has anyone found hydrometers accurate? I figured they should be, but I am guessing not?

 

[proxy001]

Good advice indeed. I shall do that tonight when I get home from work. But I still wonder, has anyone found hydrometers accurate? I figured they should be, but I am guessing not?

They can be, but full of user error.
You water should be free of debris, no air bubble, filled at exactly the right level, lay on a flat surface.
It is good to have as an emergency back up but I would not use that to correct salinity. I got a cheap refractometer from amazon. Worth the $20 . Salinity is a key component and one of the easiest to read accurately with cheap equipment.

 

[ChrisNH]

Hydrometer was usually pretty accurate for me when I used them for brewing but I don’t know what is in use for the reef hobby. I use a refractometer.

a word of caution about using rodI as a calibration point, if the device is not designed for measuring seawater it may not work well. I ran into problems using my brewing refractometer for my tank when trying to measure a salinity lower then my reference. I don’t know if that applies to hydrometers.

the best bet is what others suggested here, get a seawater reference and match that with whatever tool you are using for measuring.

 

[vetteguy53081]

Calibrate and then take a water sample to a reputable/trusted LFS and have them test for comparison.

 

[X-37B]

I am going to make a solution tonight and check.
My refrac, swing arm, and floating hydrometer all read very close to the same, 1.0265 ish.
I bought some new refrac test solution as mine was 1 year old and it read 1.028.
Got another bottle from a different lfs and it was correct.
Went back and got another bottle of the higher reading.
Same lot number and it was off also.
It was from brs for what its worth.
I trust my floating and swingarm more than my refrac.
Having more than one way to check is always good.

 

[ShepherdReefer]

Just my two cents worth. I have used a refractor meter for years in fish-only tanks. This year, when setting up a new tank for the purpose of fish and corals, I decided to install the Apex system. The salinity probe was calibrated but read differently than the refractometer. I calibrated both again and still the same issues. I purchased the Milwaukee MA887, after the calibrated...it read the same (super close) as the Apex probe and now I use just these two.

 

[SirRoadwolf]

I just bought a Milwaukee MA887 myself. We shall see what it says. Of note: my LFS used their MA887 to test my water and that is what gave the 1.038 reading.

Just my two cents worth. I have used a refractor meter for years in fish-only tanks. This year, when setting up a new tank for the purpose of fish and corals, I decided to install the Apex system. The salinity probe was calibrated but read differently than the refractometer. I calibrated both again and still the same issues. I purchased the Milwaukee MA887, after the calibrated...it read the same (super close) as the Apex probe and now I use just these two.

 

[Randy Holmes-Farley]

Good advice indeed. I shall do that tonight when I get home from work. But I still wonder, has anyone found hydrometers accurate? I figured they should be, but I am guessing not?

Many hydrometers are accurate.

 

[ShepherdReefer]

Many hydrometers are accurate.

They are...but just like just about anything, some are not. Mine is about 15 years old.

 

[Cell]

Just my two cents worth. I have used a refractor meter for years in fish-only tanks. This year, when setting up a new tank for the purpose of fish and corals, I decided to install the Apex system. The salinity probe was calibrated but read differently than the refractometer. I calibrated both again and still the same issues. I purchased the Milwaukee MA887, after the calibrated...it read the same (super close) as the Apex probe and now I use just these two.

I'm pretty sure the Milwaukee is known to read a bit high and the Apex salinity probe is not good.

 

[Randy Holmes-Farley]

They are...but just like just about anything, some are not. Mine is about 15 years old.

That's a good reason to check it with a calibration fluid.

 

[SirRoadwolf]

After checking with the calibration fluid as described in the above link, the calibrations I made based on the readings my LFS gave me, were fairly close to accurate. The swing arm float is also now showing fairly close to the same readings. However my hydrometer is still reading super low, even in the calibration fluid it is showing 1.014. Current readings about 33.5 ppt, and 1.025 SG

So, I guess I have my answer. Sadly it looks like some of my larger colonies of Coral have begun to bleach. Tho there is still a thriving colony of Zoa's which has survived those high numbers and all of that swinging!

 

[Randy Holmes-Farley]

The swing arm float is also now showing fairly close to the same readings. However my hydrometer is still reading super low, even in the calibration fluid it is showing 1.014. Current readings about 33.5 ppt, and 1.025 SG

Glad you tracked down the issue.

What type of hydrometer?

 

[SirRoadwolf]

Glad you tracked down the issue.

What type of hydrometer?

This is the Hydrometer I bought and am referring to.

Glass Saltwater Hydrometer Thermometer - Aquarium reef Soft Coral Fish Tank Test 4719857441237 | eBay

Find many great new & used options and get the best deals for Glass Saltwater Hydrometer Thermometer - Aquarium reef Soft Coral Fish Tank Test at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Randy Holmes-Farley]

This is the Hydrometer I bought and am referring to.

Glass Saltwater Hydrometer Thermometer - Aquarium reef Soft Coral Fish Tank Test 4719857441237 | eBay

Find many great new & used options and get the best deals for Glass Saltwater Hydrometer Thermometer - Aquarium reef Soft Coral Fish Tank Test at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Do you know its reference temperature? Did you use it at that specified temperature? Floating glass hydrometers are quite sensitive to temperature changes in the water.