Rising Salinity

[MJ99]

Hello, and thank you in advance for your help

I am very new to the hobby, and have just completed a 125 gallon reef tank. I am very concerned, as my salinity keeps climbing and I don't know why!

My system looks like this:

125 gallon drilled display with 2 drains & 1 return.

4 inch live sand bed filled with Florida Reef Saver live rock
30 gallon aqueon 4 sump refugium also with live sand and rock
Apex Fussion with pH, salinity, temp, orp probes
Apex Dos dosing pump
Octo Reef Skimmer
Zeovit reactor
Tunze Osmolator Ato that I fill with Ro/di (store bought) and Kalk (low dose)

I have the ato set to fill as high in the sump as I can without risking an overflow. My temp, dKH, & pH are stable, my calcium and orp are low. I have started running 2 part on the doser to raise the calcium. Thanks to the Zeo, I have untraceable nutrients.

I have a blue spotted jawfish, a hawkfish, a few snails, a shrimp, and just added 25 frags. Everyday the salinity creeps up, and is now at 37, so I will do a water change, and it will start creeping up again within the hour.

Any ideas what is causing this? I know it isn't evaporation because I have marked the sump water levels to make sure they are consistent, and the ato is going through 2-4 gallons a day. What am I missing???

 

[gone fishin]

Have you tried measuring the salinty with something other than the salinity probe?? If not that would be my first step.

 

[CarrieB]

Rising Salinity

Forgive me if this is a stupid suggestion, but you are using RO/DI in the ATO tank and not saltwater, right?

Sorry- I see you said that already.


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[nereefpat]

Good suggestions above.

I have a feeling the salinity probe is drifting on you. Take a sample in to the fish store for them to double check.

 

[Dkuhlmann]

Have you tried measuring the salinty with something other than the salinity probe?? If not that would be my first step.

Forgive me if this is a stupid suggestion, but you are using RO/DI in the ATO tank and not saltwater, right?

Sorry- I see you said that already.


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These are both my thoughts. First if you're using salt mix instead of RODI water in your ATO that is why it's creeping up. Adding water for top off should only ever be RODI water. When water evaporates from our tanks the salt is left behind this is why you top off with RODI only.

I would also have a refractometer for checking your salinity against your probe.

 

[MJ99]

Thanks for the replies. Yes, I am using Ro/di in the ato. I have a refractometer that is saying the same as the probe. This is why I am at a total loss. I moved the sensor on the ato up as high as I can, right to the very edge, and I added more fresh water today over and above what my system can hold. It isn't creeping as fast as it was, but it is creeping. If the power goes out tonight I will have a mess to clean up

 

[Capsle]

Is your salt fully dissolved when your doing your WC? Salinity shouldn't change so quickly. Over a long period of time it will very slowly creep up but definitely not in an hour.

What salt are you using?


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[gone fishin]

Odd indeed. How about large temperature swings??

 

[jpruitt]

How much 2 parts are you using and what brand. Most 2 parts are dissolved salts and can increase salinity. BRS just did a video on it a few months back about big doses of 2 part.

 

[thegrun]

+1, if you are dosing a lot of 2 part you need to skim very wet to compensate for the added salts added during dosing.

 

[MJ99]

Thank you all for your help. I just replaced my sump with a bigger model that will hold more water, thus allowing me more from the ato. I decreased the dosage of 2 part, and increased the amount of kalk in my ato. Finally, the salt has leveled out. I think you hit it right on with the 2 part being the culprit.

 

[CStrickland]

Just wanted to add that I don't see a magnesium reading in your posts. If you aren't testing it you can wind up chasing your own tail adding 2-part and kalk because when the waters low in mg, the alk and ca won't stay in suspension.

 

[alazo1]

I had a similar problem lately. I had not measured salinity in a while and when I did it was higher then I normally kept it at.
Turns out the water level in the tank was creeping up slowly. I cleaned out the overflow and tubing coming from the sump and all seems well. There must have been a small clog somewhere.