Salinity dropping.

HandofThanatos · Dec 30, 2019

I checked my salinity a week ago and it was 1.025, checked yesterday and it was 1.023. Had heard my ato go off in the middle of the night, hence the reason I had checked.

I checked again today and it was down to 1.021!

I had added 4 snails, and a protein skimmer that hasn't even gotten to the point where it is actually skimming anything yet.

I am using a refractomiter to check it, and I recalibrated it to make sure.

From what I had read keeping up on salt creep and water changes should keep it consistent and I have been on top of those because I have some expensive stuff in the tank.

Anyone have a suggestion on what might be going on, and do I just need to increase the salinity of the water I am getting from the shop to raise it by adding some salt to it so I dont shock anything?

biophilia · Dec 30, 2019

Unless your ATO failed and dumped a bunch of water into the tank (which you should be able to verify by checking your topoff reservoir), it sounds like your refractometer is acting up or you're misreading it somehow.

Also, any idea what the salinity is of the water you're getting from the LFS?

With refractometers it's really important to use them in a consistent way every time and make sure that A) there are no air bubbles trapped below the plate B) the hinged daylight plate is pressed all the way down onto the prism (sometimes a rusted pin prevents this) C) you're pointing towards a relatively consistent light source each time D) the focus on the refractometer is tuned so that the line in the eyepiece is not blurry and E) you're giving the refractometer enough time to equalize the lens and water temperature (30-45 seconds or so) before taking the reading. Hope that helps and good luck!

lapin · Dec 30, 2019

HandofThanatos said:
I checked my salinity a week ago and it was 1.025
Checked yesterday and it was 1.023.
I checked again today and it was down to 1.021!

Anyone have a suggestion on what might be going on, and do I just need to increase the salinity of the water I am getting from the shop to raise it by adding some salt to it so I dont shock anything?

To correct low salinity add water with a higher salinity when doing water changes.
I have no idea how you can lose salt, because it does not evaporate. Any spill or leak will turn white with salt creep as it drys.

WVNed · Dec 30, 2019

The most obvious cause for this is if your system has more water in it now than it did when you filled it with saltwater. Is the water level higher in any sections of your system now compared to when you filled it?

Brandonphem · Dec 30, 2019

HandofThanatos said:
I checked my salinity a week ago and it was 1.025, checked yesterday and it was 1.023. Had heard my ato go off in the middle of the night, hence the reason I had checked.

I checked again today and it was down to 1.021!

I had added 4 snails, and a protein skimmer that hasn't even gotten to the point where it is actually skimming anything yet.

I am using a refractomiter to check it, and I recalibrated it to make sure.

From what I had read keeping up on salt creep and water changes should keep it consistent and I have been on top of those because I have some expensive stuff in the tank.

Anyone have a suggestion on what might be going on, and do I just need to increase the salinity of the water I am getting from the shop to raise it by adding some salt to it so I dont shock anything?

It could possibly be the salt is drying out somewhere like my qt bio wheel tank makes water go everywhere making me lose salt out the tank this could be the only explanation I can think of other then a ato failure

Lithoman · Dec 30, 2019

Unless he has a leak and ato is refilling with water.. any possible leaks?

WVNed · Dec 30, 2019

You can tinker with your overflow and get this much of a change. The water level rises in the DT and the ATO makes it up. You can adjust your ATO sensor and cause it to.

Saltyreef · Dec 30, 2019

Agreed with above. I think the desired water level needs to be pinpointed and marked, and then ensuring the ATO is only refilling to this point and no more.
Also check the water from your LFS for consistant salinity. Whatever it is, your tank should be. I would assume theyre just using bulk filtered NSW so all should be good with salinity levels.

huckjai · Dec 31, 2019

How big is your tank? When I added my protein skimmer, it lowered the level of my sump when it pumped the water into it, which caused my ato to go off and add more water. Didn't affect my salinity as I have a 95 gallon tank with a 40 gallon sump. But I'd imagine a tank small enough may get affected.

Also make sure you are testing water from the same place. I noticed that I'd get different readings if I took water from the top surface, vs somewhere a bit deeper.