I suck at salinity

Discussion in 'Reef Chemistry' started by kinetic, Sep 18, 2017.

  1. kinetic

    kinetic Webmaster

    I have two separate calibration solutions, and they're both reading exactly the same (Pinpoint and BRS) which is a good sign.

    But I can't seem to get my salinity right in my (now cycling) tank. I followed AquaForest Reef Salt directions and somehow ended up with 50 ppt salinity (right after a calibration).

    Over the next day, I siphoned out probably 20 gallons of water and replaced it with RO/DI and got it down to, what I thought was 35 ppt.

    A day later, I noticed the salinity was back up to 40 ppt. I checked the 35ppt over an hour after I replaced the RO/DI water into the tank, so I thought that was enough time, but I guess not. So I removed more and waited 24 hours and I was back to 35 ppt.

    Today, 4 days later, I tested it again since I setup my ATK, and got a reading of 30 ppt. UGH. I checked my refractometer and it was calibrated still.

    I just added 4 cups of salt in (43 total water volume) to see if that'll get it up to 35 ppt.

    How long should I wait until the salinity stabilizes? I really suck at this...
  2. kinetic

    kinetic Webmaster

    Also, after I added 4 cups of salt, my overflow got backed up a bit and started draining into the emergency drain. I opened up my drain valve a bit more, and now my sump's return pump chamber probably gained 3 inches of water. What the what? Is this possible from just adding 4 cups of salt?
  3. RandyC

    RandyC Supporting Member

    Does your refractometer have auto temperature correction (will likely have a sticker with ATC on the unit if it is). If it's not auto correcting, could be why you're getting wacky results. Also, make sure there are zero bubbles under the cover when measuring.

    To be honest, while hand held refractometers do work, I got real lazy about calibration and screwed myself once too and Iused to think the Milwaukee digital refractometers was a little overkill because of the price ($115), but it's made life much easier not having to find the right light or have to calibrate all the time. I'd never go back to non-digital refractometers.

    Gablami likes this.
  4. Gablami

    Gablami Supporting Member

    I also love the Milwaukee. Do yourself a favor and get yourself one of these. You will never go back.

    Sent from my iPhone using Tapatalk
  5. yellojello

    yellojello Supporting Member

    Did you add salt directly to the tank/sump, or premix separately in a saltwater mixing container?
  6. yellojello

    yellojello Supporting Member

    You should never put salt directly into tank. I know you don't have anything in it yet, but it's a big no no. Salt wouldn't fully circulate and dissolve right away, thus getting delayed increase of salinity. Need to full dissolve and premix in separate container to get an accurate reading, adjust, then add to tank.
  7. coral4me

    coral4me Supporting Member

    A good rule of thumb to get the salinity close when mixing salt is to use 1/2 cup salt per 1 gallon of water.
  8. Vincerama2

    Vincerama2 Evil Overlord

    I use a refractometer and when it's *around* 1.026, I call it good. I never worry about such small variances.

    Maybe this is why my tank sucks.
    ashburn2k likes this.
  9. kinetic

    kinetic Webmaster

    No ATC on mine. My refractometer I bought back in 2005... I'm not sure ATC existed back then. Maybe it did. I'll look into the Milwaukee.

    I don't disagree. I was just hoping it would dissolve eventually. Though I believe even 1 hour isn't enough. I wouldn't do this except on a new tank, though it is a bit difficult and I'll probably try a different method next time.

    AquaForest Reef Salt has weird instructions. I'm also unsure if I did the math correctly the first time. Actually they're not weird at all, I'm just certain I probably screwed up on my metric conversions.

    lol that is the spirit!

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