Where's all the salt going?

[Julbra]

Did anyone else notice their salinity decreasing very slowly over time? For example dropping 0.1-0.2ppt per week?

It got me thinking. Why is that? I thought of several suspects.
1. Skimmer cup filling up?
2. Salt creep around the pipes and edges of the aquarium?
3. General precipitate (e.g. calcium carbonate) for example on warm pumps and wave makers?
4. Corals and snails growing?
5. Something else?

My best guess is that the skimmer alone can be responsible for the vast majority of the lost salt.
I am assuming that skimmate is basically saltwater with added organics. If you empty about 1L per week out of a 400L at 35ppt that equates to around 0.09ppt salinity decrease!

Help me elucidate the mystery of the missing salt.
Note: this is not testing error, this has been happening consistently every week for over a year and checked with a well calibrated salinity meter.

 

[exnisstech]

Need an option to choose mine doesn't drop

 

[Spare time]

If your skimmer is taking out that much water you might want to adjust it to run dryer. If anything, most people should eventually see salinity going up if they are dosing regularly.

 

[((FORDTECH))]

Did anyone else notice their salinity decreasing very slowly over time? For example dropping 0.1-0.2ppt per week?

It got me thinking. Why is that? I thought of several suspects.
1. Skimmer cup filling up?
2. Salt creep around the pipes and edges of the aquarium?
3. General precipitate (e.g. calcium carbonate) for example on warm pumps and wave makers?
4. Corals and snails growing?
5. Something else?

My best guess is that the skimmer alone can be responsible for the vast majority of the lost salt.
I am assuming that skimmate is basically saltwater with added organics. If you empty about 1L per week out of a 400L at 35ppt that equates to around 0.09ppt salinity decrease!

Help me elucidate the mystery of the missing salt.
Note: this is not testing error, this has been happening consistently every week for over a year and checked with a well calibrated salinity meter.

My salinity goes up each week

 

[Randy Holmes-Farley Verified Community Expert]

Skimming reduces salinity slowly. The other choices are not significant in most cases.

 

[Julbra]

My salinity goes up each week

Do you use an auto top off? Curious to know how salt can increase.

 

[Julbra]

If your skimmer is taking out that much water you might want to adjust it to run dryer. If anything, most people should eventually see salinity going up if they are dosing regularly.

The numbers I gave were just as an example. I have not actually measured the capacity of my cup. The point being that if you use a skimmer you will take some salt out over time that needs to be replaced.

Also, in my experience, dosing Alkalinity and Calcium does not change the conductivity of the solution compared to the Salt!

 

[Mark Goode]

Apex salinity probe 'drift'.

 

[slythy]

Apex salinity probe 'drift'.

when mine drifts its all but gradual. It looks like someone dropped 10 cups of salt in my tank lol

 

[Randy Holmes-Farley Verified Community Expert]

Salinity rise is typical for anyone using independent alk and calcium additives. They bring in lots of other ions.

 

[((FORDTECH))]

Do you use an auto top off? Curious to know how salt can increase.

I have no idea but it always drifts up to 1.027 and I have to correct it. I use brs 2 part with tm balling method with the part c. I believe this is something to do with it and I think it’s actually in the instructions as well

 

[((FORDTECH))]

Do you use an auto top off? Curious to know how salt can increase.

As randy said above my post

 

[Stanley Wong]

Evaporation only remove water (not counting the ATO) only, right ?

 

[Randy Holmes-Farley Verified Community Expert]

I have no idea but it always drifts up to 1.027 and I have to correct it. I use brs 2 part with tm balling method with the part c. I believe this is something to do with it and I think it’s actually in the instructions as well

Yes, a substantial salinity rise is expected for all two part systems.