How to lower salinity?

[FishmanJosh]

My 20g marine has had a few problems as of late, and I have just bought a refractometer to replace my swing arm hydrometer. In doing this I have discovered that the salinity levels in the tank are actually quite high - around 1.030.

So my question is: How do I go about lowering the levels? I could do a water change and replace with only RO water but I am worried this might give the fish a shock. I could also gradually replace my water by doing lower salinity saltwater changes over a few months. What would be the best course of action?

Thanks for your help

 

[Raimond]

Getting accurate equipment is great!
There are many opinions on how to accomplish this. My way is not the only way...
I mix water lower than my tank water by .01 and do several small changes a day apart.

As your tank is 20G, I would change 2G each day until you get to where you want to be. This way you are headed towards your goal slowly and completing your PWC's at the same time. Be sure to test your water for the same PH as well.

Hope this helps...

 

[melosu58]

I just lower the salinity of my PWC water and it lowers it little by little which is the way you want it.

 

[mellowyellow]

Fishman: I'm sure you already know so this is just a reminder. As your water evaporates and you add new water, simply add fresh water to your tank because the salt doesn't evaporate.

 

[FishmanJosh]

Yeah I know haha. Thanks anyway, but the reason (we think) its high is because of the fiarly inaccurate swing arm. Thanks for your replies everyone

 

[mellowyellow]

I'm still using the swing arm, but I must get a refractometer (spelling) soon. I've invested in everything else. Why not? I also just installed UV sterilizers in both my salt and fresh tanks. Works great. The water is crystal clear and that alone makes me happy. I've always had a problem with hazy water.

 

[Raimond]

You just can not get a reliable reading on a swing arm... I have 2 and they both read differently than my refractometer. One is close so I use it to get my new water close and then switch to the refractometer for the final adjustments.

 

[mr_X]

a word of advice:
periodically re-calibrate your refractometer, because they do get out of whack.

 

[ryshark]

Lowering the SG/Salinity is not as stressful on the fish as rasing it. You can do lower salinity partial water changes as people suggested. Or what I would do is is replace water from you tank with Temp and PH adjusted RODI water and lower the SG by .001 every day until you are where you want to be. So day one you would go from 1.030 to 1.029, day-2 you would go down to 1.028 etc etc. Read up on hyposalinity treatment for Crypt/Ich, it should give you an idea of what percentage of water you need to replace with rodi water to lower your size tank down by .001 per day.
Like mr_x said, you should recalibrate your refractometer often. I recalibrate mine before every partial water change using a refractometer calibration solution. The solution is more accurate than using rodi or distilled water because it is closer to the range our tank is, like 1.025 or 35ppt

 

[cabezon]

Or just take a big cup of salt water out of the tank and pour a big cup of RODI in.