Need some help with my salinity

[ebeez]

Hi,
I have a 120 gal FOWLR and a 30 gal sump. Water temp is 78-79 .. all monitored my my Apex controller. I found my salinity was measuring 26 in the past week which I knew was incorrect. Used a hydrometer and got 30 ppt and got the same reading from my refractometer. I thought the probe had given out on me as it is a few years old so I got a new probe, calibrated it and i'm still getting the same reading? I tested the probe in 53000 solution and it measured 34.9 ppt. I've done the obvious like lightly tapping to release air bubbles.. still reading 26.

Any thoughts/ideas would be appreciated

 

[TheEngineer]

Do you have an ATO? If so, does it get fed from a reservoir or direct from a RODI unit? Have you noticed more water going in than usual? And finally, any chance you have a leak?

 

[potatocouch]

Do you see anything unwell with your system @ebeez ? fish dying perhaps?

 

[ebeez]

Do you have an ATO? If so, does it get fed from a reservoir or direct from a RODI unit? Have you noticed more water going in than usual? And finally, any chance you have a leak?

Hi, yes I have an ATO fed from a bucket with RODI water. no leaks and ATO has not been going on more than normal. If thst was the case I would think that all 3 tools would measure the same

 

[ebeez]

Do you see anything unwell with your system @ebeez ? fish dying perhaps?

no all are good and healthy

 

[TheEngineer]

Hi, yes I have an ATO fed from a bucket with RODI water. no leaks and ATO has not been going on more than normal. If thst was the case I would think that all 3 tools would measure the same

I don't trust anything a hydrometer says. When did you last calibrate your refractometer? And how?

 

[ebeez]

brand new refractometer. calibrated it today with RO water and zero'ed it out... twice

 

[TheEngineer]

brand new refractometer. calibrated it today with RO water and zero'ed it out... twice

I'd try it with some 35ppt calibration fluid. You can buy it from a LFS (have them test your water too while you are there) or you can make your own.

 

[ebeez]

I'd try it with some 35ppt calibration fluid. You can buy it from a LFS (have them test your water too while you are there) or you can make your own.

I will try that next.. thanks for the suggestion!

 

[Randy Holmes-Farley Verified Community Expert]

What units are you using when you say the salinity is 26? ppt?

And other methods say 30 ppt?

Both of those are low and would suggest raising it is appropriate.

The conductivity probe is temperature compensated. When measuring and calibrating, the APEX temp probe needs to be in the same solution (or at least the same temp) as the fluid being measured or used for calibration.

 

[ebeez]

What units are you using when you say the salinity is 26? ppt?

And other methods say 30 ppt?

Both of those are low and would suggest raising it is appropriate.

The conductivity probe is temperature compensated. When measuring and calibrating, the APEX temp probe needs to be in the same solution (or at least the same temp) as the fluid being measured or used for calibration.

Wow I feel like a doofus. I guess my salinity level is 26ppt. I re-calibrated the refractometer with RODI water again and tested twice to get the same as the probe. I'm struggling to see how the ATO put that much fresh water in over a week? Well lesson learned.. now to raise it back up slowly.
Thanks to everyone in the forum for their assistance!

Eric

 

[TheEngineer]

To go from 35ppt to 26ppt in a 120 gal tank would require replacing around 31 gallons of water with straight RODI. I'm skeptical of your test.

Did you go through 30 gallons?

 

[ebeez]

To go from 35ppt to 26ppt in a 120 gal tank would require replacing around 31 gallons of water with straight RODI. I'm skeptical of your test.

Did you go through 30 gallons?

sorry.. not in a week.. I meant to say in 1 month. I mistyped it in my original post as well.

 

[TheEngineer]

You think you lost and replaced 30 gallons of water in a month? Salt doesn't evaporate so this water has to come out of the tank. Either you had to remove that much water or you have a pretty sizable leak.

Have you been doing water changes?

 

[ebeez]

You think you lost and replaced 30 gallons of water in a month? Salt doesn't evaporate so this water has to come out of the tank. Either you had to remove that much water or you have a pretty sizable leak.

Have you been doing water changes?

yes I do regular water changes (10-15 gal) a week. The only thing I can think of is I miscalculated the salt that I mixed into the buckets. I also switched salt mix on my last purchase (Red Sea Corla Pro Salt to Instant Ocean).. I need to look at the new bucket. I'm just glad I didn't have any loss of fish.

 

[TheEngineer]

yes I do regular water changes (10-15 gal) a week. The only thing I can think of is I miscalculated the salt that I mixed into the buckets. I also switched salt mix on my last purchase (Red Sea Corla Pro Salt to Instant Ocean).. I need to look at the new bucket. I'm just glad I didn't have any loss of fish.

Do you test the salinity or just measure and go?

 

[ebeez]

Do you test the salinity or just measure and go?

measure and go.. that's where I fell down.. been in the hobby for almost 9 years.. never screwed up like this before.. hence feeling like a doofus!

 

[TheEngineer]

measure and go.. that's where I fell down.. been in the hobby for almost 9 years.. never screwed up like this before.. hence feeling like a doofus!

Well we all cut corners at some point just raise the salinity slowly. You can drop faster than you can raise it. Also, is still get someone else to test your water. Just to be sure.

 

[ebeez]

Well we all cut corners at some point just raise the salinity slowly. You can drop faster than you can raise it. Also, is still get someone else to test your water. Just to be sure.

Never too old learn learn a new lesson! Going to the LFS tomorrow. Thanks again for all the assistance.

 

[TheEngineer]

Good luck! Keep us updated on your progress.