Need advice for lowering salinity

[RocksNStuff]

Hi all,
I was using a hygrometer until about 3 weeks ago when I bought a refractometer and calibration solution.

When I was using the hygrometer, I was reading a constant 1.024 SG.

When I calibrated the refractometer and measured, the tank was at 1.030.

My plan for lowering the SG is to make small water changes and just replace water with RODI.

Is this a good plan and over how long should I do this?

For example, if I want to get down to 1.026, should I do this over a few weeks? Few days? What's the safest approach?

 

[schuby]

Safest would be over 2 weeks, IMO.

 

[blaxsun]

Or you can just mix a batch of saltwater that has a much lower salinity. I’d maybe do it once a week until you get the salinity where you want it to be.

 

[RocksNStuff]

Or you can just mix a batch of saltwater that has a much lower salinity. I’d maybe do it once a week until you get the salinity where you want it to be.

Good idea. But I do have something competing against the high salinity. Low Nitrates. Like 0 Nitrates. I'm trying to get them up by feeding but can't seem to. This is all to say that I'd like to do as little water change as possible. Does that make sense?

 

[blaxsun]

Good idea. But I do have something competing against the high salinity. Low Nitrates. Like 0 Nitrates. I'm trying to get them up by feeding but can't seem to. This is all to say that I'd like to do as little water change as possible. Does that make sense?

It does, but remember that slow and steady wins the race here. Your salinity is probably +0.04 to +0.05 higher than it should be, and its’s taken your reef inhabitants a while to grow accustomed to it. You don’t want to shock their system with a drastic change. A 10% water change every week over a few weeks isn’t going to torpedo your nitrate efforts.

 

[JCM]

Lowering the salinity isn't hard on the tank inhabitants like raising it is. Just suck out a few gallons and replace with RODI. spending weeks dropping salinity from 1.03 to 1.026 is completely unnecessary.

 

[revenant]

Parts of the Red Sea are probably 1.03…

 

[JCM]

Parts of the Red Sea are probably 1.03…

It absolutely is. And it has some the best reefs around.

 

[revenant]

It absolutely is. And it has some the best reefs around.

Yessir. My point exactly.

 

[RocksNStuff]

Yessir. My point exactly.

Fair point. Is 1.03 too high? General question...

 

[RocksNStuff]

Lowering the salinity isn't hard on the tank inhabitants like raising it is. Just suck out a few gallons and replace with RODI. spending weeks dropping salinity from 1.03 to 1.026 is completely unnecessary.

Is that based on personal experience or...?

 

[revenant]

Fair point. Is 1.03 too high? General question...

I’d say maybe not ideal from what we’re used to but reefs clearly thrive in that salinity..

 

[RocksNStuff]

I’d say maybe not ideal from what we’re used to but reefs clearly thrive in that salinity..

Yeah. I'm trying not to be a number chaser but I also don't want to ignore it...kinda tricky.

 

[JCM]

Is that based on personal experience or...?

Almost 20 years worth, yes.

 

[Dkmoo]

my tank fluctuates by 0.001SG every 3 days b/c i manually top off RODI. so figure if you with the same rate you should be safe. This equates to 3 weeks to lower your 1.030 to 1.024

 

[RocksNStuff]

Almost 20 years worth, yes.

I guess I should ask if you were in my shoes, how would you do it? Or would you even lower the tank's SG?

 

[schuby]

Are you running GFO, ATS, or macro-algae?

 

[RocksNStuff]

Are you running GFO, ATS, or macro-algae?

None of the above. Nitrates were steady at 10 to 15ppm then I added about 10lbs of live rock and they dropped to zero )

 

[Suohhen]

I love these discussions about what range of salinity is safe. Sure 1.03 might be okay but there are other issues. It puts you closer to the edge of safety. It is far away from what the stock you are acquiring is kept at. Sure you could slowly acclimate them during qt, if you qt everything that goes into your tank, but that is extra work and the salinity is already usually more around 1.023-21 from the LFS. It isn't balanced with the ratio of elements found in your salt. So every time you do a water change your increasing certain elements more than the average which may not be an issue with say alkalinity which can deplete so fast regardless, but who likes to have disruptions to their dosing? So please stop with the Red Sea argument. If you want to keep a higher salinity feel free, but it is not good advice.

 

[JCM]

I guess I should ask if you were in my shoes, how would you do it? Or would you even lower the tank's SG?

Yes, I would personally. I would drop it to ~1.028 one day, then drop it to ~1.026 in the next day or two. That's where I keep mine.