How to Fix a Dosing Mistake: High Cal with Low Alk

Discussion in 'Reef Chemistry by Randy Holmes-Farley' started by divetoday, Nov 11, 2017.

  1. divetoday

    divetoday Member R2R Supporter Build Thread Contributor

    May 9, 2017
    Likes Received:
    Fort Lauderdale
    Hi folks: long story short but after Hurricane Irma I have been dosing calcium but not alkalinity. I checked my 2-part dosing with Apex immediately after the storm, and all seemed fine on the Fusion console. Unfortunately, I forgot to prime the DOS after that major loss of power, so the pump head kept spinning but nothing was drawing from the container. (This is my first 6 months with both the Apex and 2-part dosing.)

    I have done two 30% water changes since the storm, but my calcium is higher than my salifert test can read, and my alk has fallen to 6.8. In attempting to read up about how to deal with this situation, I have found an article that says to dose both elements in the same amount even if you want to raise only one. That doesn't make a lot of sense to me, but I would like to get some feedback before following through on that. My target dose with alkalinity would be 8.8. Thanks for any input.

  2. Randy Holmes-Farley

    Randy Holmes-Farley Reef Chemist Staff Member Team R2R R2R Supporter R2R Excellence Award Article Contributor Expert Contributor

    Sep 5, 2014
    Likes Received:
    Arlington, Massachusetts, United States
    It is fine to dose just the alk part of a two part if calcium is already too high. So keep dosing alk as needed.

    Second step is to determine the actual calcium level by using another syringe or two to get to the actual endpoint, and add the values together.
  3. saltyfilmfolks

    saltyfilmfolks Lights! Camera! Reef! R2R Supporter R2R Excellence Award Photo of the Month Award Reef Squad Leader Build Thread Contributor

    Feb 25, 2014
    Likes Received:
    Dose evenly. Continue water changes for a month on a regular schedule. Onnce or twice a month or whatever you do.

    After a month or two, you'll see if there is an imbalance in the cal and alk. Then increase the dosing for the one that is low. This will be different with every salt mix.
    Some that are balanced salts will likely not need uneven dosing.

    Keep in mind out tests are not that great. So test error is common. So just get close.

    The reason to dose evenly is the use is always even.
    By dosing evenly you can see the next step you need to take. Or tanks one at all.

    I preferred to do a series of one a week wc for a few week to the the tank closer to my salt parameters before starting my guesses on the initial dose.
    divetoday likes this.
Draft saved Draft deleted

Share This Page