How slow should I pace salinity increase?

[mbarber87]

Newer to the hobby and am quickly learning how unreliable the Apex salinity probe is. Even after careful calibration, it was still underreporting around 3-4ppt. I have been slowly trying to lower the salinity over the past few days, but with evaporation on a 150gal tank, it's taking a lot longer. Right now, I am just removing 2-3 gallons of tank water and replacing with RODI water. I am at about 1.0275 and am trying to get it to 1.025. I like 1.025 because where I get the majority of my coral from at the LFS, they keep theirs at 1.025.

How big would a .002sg swing be on a 150gal tank?

 

[andrewey]

I would first check this out so you don't overshoot anything:

Target Salinity Calculator

Aquarium calculator; Create a water-change schedule that can be used to reach a target salinity.

www.hamzasreef.com

After that, I would plan on lowering it over the course of a week.

 

[WVNed]

~ 2 hours
Reasonable salinity changes should take no longer than it would take to acclimate a new specimen to your tank. You are simply acclimating everything in the tank at once.
The trick with a whole system is to make sure you give the water time to completely mix before you do each test so you dont get a false reading and overshoot your target.

 

[mbarber87]

Thanks all!

 

[mbarber87]

I would first check this out so you don't overshoot anything:

Target Salinity Calculator

Aquarium calculator; Create a water-change schedule that can be used to reach a target salinity.

www.hamzasreef.com

After that, I would plan on lowering it over the course of a week.

Hey where in VA are you located? I am in SW-VA region!

 

[AcroNem]

I agree with Ned, I have made those changes over the course of a day or a couple hours many times. I'd like to say though, a SG of 1.027 is totally fine. Salinity on many reefs can be higher than where a lot of us keep our systems at.

 

[andrewey]

@mbarber87, I'm in Salem!

 

[mbarber87]

I agree with Ned, I have made those changes over the course of a day or a couple hours many times. I'd like to say though, a SG of 1.027 is totally fine. Salinity on many reefs can be higher than where a lot of us keep our systems at.

100% agree. It obviously could be a number of other factors as well, but my Zoanthids in particular seem to do SO much better (in terms of size) with 1.025 compared to 1.027

 

[mbarber87]

@mbarber87, I'm in Salem!

Oh no way! I am in Christiansburg! Is there an active local reef club around?

 

[mike550]

@mbarber87 the site that @andrewey points you to has a lot of great calculators including one that shows the change in concentration using water changes so you can figure out roughly how much RODI you need to use to dilute. The overall salinity change is about 3ppt which isn’t huge, and I think replacing a few gallons with RODI every couple of hours will get you there pretty easily.

 

[AcroNem]

100% agree. It obviously could be a number of other factors as well, but my Zoanthids in particular seem to do SO much better (in terms of size) with 1.025 compared to 1.027

That's fine then. Every system is different. You're right it could be many things, including if it swung up fast or other parameters are too high in your system at that salinity. But still, if it's better at 1.025 that's what matters.

 

[Randy Holmes-Farley Verified Community Expert]

Newer to the hobby and am quickly learning how unreliable the Apex salinity probe is. Even after careful calibration, it was still underreporting around 3-4ppt. I have been slowly trying to lower the salinity over the past few days, but with evaporation on a 150gal tank, it's taking a lot longer. Right now, I am just removing 2-3 gallons of tank water and replacing with RODI water. I am at about 1.0275 and am trying to get it to 1.025. I like 1.025 because where I get the majority of my coral from at the LFS, they keep theirs at 1.025.

How big would a .002sg swing be on a 150gal tank?

sg = 1.0275 is not very high at all and there is no need to rush it down.

My target would be 1.0264, which is equivalent to 35 ppt seawater, but I can see the benefit to matching an LFS even if their salinity is a bit low.

 

[Randy Holmes-Farley Verified Community Expert]

100% agree. It obviously could be a number of other factors as well, but my Zoanthids in particular seem to do SO much better (in terms of size) with 1.025 compared to 1.027

Maybe you should rescue them from the ocean! lol

 

[2Sunny]

Newer to the hobby and am quickly learning how unreliable the Apex salinity probe is. Even after careful calibration, it was still underreporting around 3-4ppt. I have been slowly trying to lower the salinity over the past few days, but with evaporation on a 150gal tank, it's taking a lot longer. Right now, I am just removing 2-3 gallons of tank water and replacing with RODI water. I am at about 1.0275 and am trying to get it to 1.025. I like 1.025 because where I get the majority of my coral from at the LFS, they keep theirs at 1.025.

How big would a .002sg swing be on a 150gal tank?

I will second the notion that moving 3 ppt is no big deal and can be done in 2 hours, and 35 ppt is the target used by most long time reefers.

How did you get your reading which you believe is more accurate?

Also awesome article on the whole topic here:

Refractometers and Salinity Measurement