Salinity keeps dropping

[Yamil Montanez]

Can anyone shine some light? I keep getting Neptune alarms about my tank salinity. I have approximately 300 gallons of water volume in a mix reef tank. My ATO is a 5 gal. Container. I usually run my tank at 1.026 for salinity but for the past days it has being dropping and it's currently reading 1.023. I checked my ato and its working properly. Does anyone knows what would affect my salinity other that temp?

 

[HB AL]

I would bet that the measuring device/probe your using is giving you erroneous #s, since you say the ato is working properly. In a large system like yours you would need to be dumping in quite a bit of freshwater to see such a large drop in a few days or so. There really isn’t any other way to drop salinity that quick without a bunch of freshwater entering the system. Before you attempt to bring it up possibly causing adverse effects I would measure your salinity with whatever else you have, refractometer, take a sample to your lfs etc....

 

[Yamil Montanez]

I did texted with a Milwaukee digital text and it did confirmed my Neptune reading.

 

[Yamil Montanez]

I have noticed that my ORP went up to 407

 

[HB AL]

If your absolutely sure freshwater in a large enough volume to effect salinity quickly didn’t enter the tank I would use some other options and test the water again with other devices. Exactly how sudden was the drop, hours, days, weeks? Other than a lot of freshwater quickly entering your large system I don’t know how your salinity could drop like that in a matter of hours or days. Hopefully someone will chime in with another possible way they’ve experienced a sudden drop in salinity without the addition of freshwater. Weird thing is salinity is the easiest thing to keep stable. Following along for a resolution.

 

[Yamil Montanez]

It has being dropping gradually for the past few days

 

[HB AL]

I’m out of answers if your readings are correct and extra freshwater didn’t enter the system.

 

[PaulPerger]

Your ATO container for a 300+ Gal system is a five gallon container?! Seems very small...

 

[acabgd]

Are you sure you don't have a leak somewhere? That would be the only logical explanation.

 

[lapin]

It has being dropping gradually for the past few days

When water evaporates it leaves behind the salt. So we know salt water is leaving the system
300 gallons of salt water at 1.026. and it dropped to 1.023 in 3 days. How many times have you filled the 5 gallon ATO in those 3 days?
This will tell you how many gallons of saltwater you have lost.
Does your skimmer dump out into a drain?

 

[Yamil Montanez]

I did found water, about half gallon in a bucket under my frag tank which tells me that I do have a small leak. Thanks for all the help!

 

[Yamil Montanez]

Here is the graph of my salinity

 

[lapin]

Replacing 1/2 gallon in a 300 gallon system would not drop it that much. You might look for other leaks.

 

[HB AL]

Here is the graph of my salinity

Sure looks like you lost quite a bit of saltwater and was quickly replaced with freshwater, I thing you have your smoking gun. Did ya ever figure out what went wrong?

 

[vetteguy53081]

I would calibrate probe and more important take a water sample to trusted LFS for reading and comparison with your gage

 

[ScottR]

I’ll weigh in with another possibility, if you’re mixing your salt water and taking a reading before adding new water to the tank, you’ll probably have a higher reading. For example, I’ll make a 5 gallon batch and measure everything out correctly. If I take a reading right away, I’ll have 1.030. An hour or two later, it’ll get down to 1.026 or so before eventually settling down to my target of 1.025. Also, if you have a leak, I would think the same ratio of salt to water would be leaving. So I don’t think a leak would cause this. If you do a water change and take out that same amount of water and take a reading, you shouldn’t have a drop in salinity. You could also take a reading of your leaked water. Does it have a higher salinity to that of your aquarium?

 

[Stanzo13]

When water evaporates it leaves behind the salt. So we know salt water is leaving the system
300 gallons of salt water at 1.026. and it dropped to 1.023 in 3 days. How many times have you filled the 5 gallon ATO in those 3 days?
This will tell you how many gallons of saltwater you have lost.
Does your skimmer dump out into a drain?

Water would be leaving the system, salt doesn't evaporate.

 

[ScottR]

Here is the graph of my salinity

Just curious, are you also taking manual readings? Technology can go awry sometimes.

 

[Saveafish]

At 300 gallons. To drop it. 1.026 down to 1.023 you're looking at adding 23 gallons. I mean take out 23 gallons of salt and add 23 gallons of fresh. Top off wont do it.
Did you do a water change and use fresh and not salt.
Don't use the meters. Use a refractor to double ck.

 

[ScottR]

At 300 gallons. To drop it. 1.026 down to 1.023 you're looking at adding 23 gallons. I mean take out 23 gallons of salt and add 23 gallons of fresh. Top off wont do it.
Did you do a water change and use fresh and not salt.
Don't use the meters. Use a refractor to double ck.

I agree. Salinity tends to be quite stable. To have a large drop like this would take a manual change. Especially in a large tank like that.