Alk cal increasing and phos and nit decreasing

Discussion in 'Water Chemistry' started by Jon.Peak, Mar 12, 2015.

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  1. Jon.Peak

    Jon.Peak Fire Worm

    Feb 28, 2011
    Southern Illinois
    Need some help.
    I have a few questions about basic or advanced reef chemistry.
    I have begun keeping some acros and for the first 2 weeks they looked great.
    They were coloring up and polyps were extended.

    Two weeks ago water chemistry 2/27
    Cal 465
    Alk 10.5
    Mag 1460
    Phos .5
    Nit 5.0-7

    Water chemistry was slowly improving so I decided to try the acros.

    After noticing my acros tips turning white and polyps not extending I did some more tests....

    Cal 450
    Alk 9.2
    Mag 1280
    Phos 0-.25
    Nit 0-2.5

    That's when I decided to stop the dosing of part A and B because I thought the numbers where too high for only 2 acros and that possibly as my phos and nit we're decreasing maybe I needed to decrease my Cal and Alk.

    Can anyone help me understand the relationship between Alk, Cal, Phos and Nit.

    Is my understanding correct..... That as the Phos and Nit decrease to almost undetectable so should my Alk and Cal.

    And if so what is the best way to decrease them.
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  3. mdbostwick

    mdbostwick Vlamingii Tang

    Feb 21, 2013
    Canton OH
    Your alk and cal will decrease as your corailline algae grows and as the stony corals start to grow. Those levels are actually good where they are and you want them to stay as stable as you get them, be it alk 8-12 or cal 350-500. You want your cal to be about 1:3 ratio Cal to Mag.

    The alk will more than likely be the first one to fluctuate. If the tips are burning you may want to monitor the alk throughout the day.

    Are you using a dosing pump for your 2 part? How many stony corals do you have and how big are they? You may be able to keep your alk and Cal stable using only WCs if you have a small amount consuming them.

    How often are you doing a WC? What percentage? What type of salt are you using?

    Burnt tips could also be due to lighting. How old are the T5s and what kind? Are the LEDs just spectrum or for coral growth? Linking the bulb will probably help.

    Are you able to post a picture of the corals?

    How stable is your temperature? You want to try to rule out any STN or RTN as well.

    Lots of factors could be playing a role so a little more info should be able to help.
  4. Corailline

    Corailline Super Moderator Staff Member

    Sep 8, 2010
    It is a dry heat, yeah right !

    The 1st link does address some of your questions. You may have decreased the values too quickly.

    The lower your N/P values then yes your Alk should be around the 7-8 mark with an ULNS or you will see stressed corals with burnt tips.

    Your Ca number should pretty much stay around 350-450 without much intervention on your part.

    I definitely agree with stopping the two parts for now, you simply do not need Ca/Alk values that high. I run around 7.5 alk with a lot of sps. Shoot for values more consistent with NSW for now. Stick to water changes and you should be fine for months to come.