Dosing Alk with Apex

Discussion in 'Coral' started by Schmitty, Nov 10, 2017.

  1. Schmitty

    Schmitty Supporting Member

    Ok, so I got one for you guys. Ive been dosing alkalinity daily with my apex controller. Im currently doing about 11.5 ml daily to keep the alk at 9. Here's my question though, do you recommend dosing the 11.5 ml over 24 hrs (which is what Im currently doing) or dosing a larger amount at the lowest ph peak to keep the ph more stable thru the off light hours(which is what Im thinking of doing)?

    Also, Im thinking that maybe dosing more less often could be better for the dosing pump? Thoughts???
     
  2. JVU

    JVU Supporting Member

    I’m also interested to hear what people think about this.

    I was dosing at night to partially offset the drop in pH at night, with the understanding of the limitation that 2-part dosing doesn’t dramatically affect pH so there is probably only a small effect. Also so I wouldn’t hear the pump in my family room during the day.

    I recently moved my pumps out the garage with a pass-through so the noise part went out of the picture.

    Also, I recently started thinking that maybe it is better to dose throughout the 24-hours because there is a little more alk consumption during daylight hours than at night, and if we are trying to avoid swings in alk, then dosing throughout the 24-hours is probably better.


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  3. rygh

    rygh Supporting Member

    Most dosing pumps cannot handle 100% duty cycle for extended periods.
    Other than that, I don't really think it matters much. Alk does not swing that fast.
    For Kalk dosing, which has a pretty strong effect on PH, dosing spread out over the 12 hour night period might be optimal.
     
  4. Bruce Spiegelman

    Bruce Spiegelman Supporting Member

    Normally Alk is dosed at night as an off-cycle to calc. This helps keep PH from swinging too much. So most folks ( I think) usually set up a 1--12 hour cycle at night for Alk and a 10-12 hour cycle during he day for calc.
     
  5. MolaMola

    MolaMola Supporting Member

    Piggy back question - so if I were to set up my dosers I might want to try dosing Alk during the day? I need the reverse of normal, since my pH drops all day from students breathing and rises markedly when they go home and continues rising during the night. As for the Ca, I did not think to dose that at opposite times, just thought you stagger it by minutes between Alk dosing.
     
  6. Bruce Spiegelman

    Bruce Spiegelman Supporting Member

    Makes sense -- worth trying it that way. Staggering works as well, but its just easier to set up a long dosing period on most dosers over a 10-12 hour period than to set up one at 1 Pm, 1 at 2Pm, then the next at @:30 as nauseum.
     
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  7. JVU

    JVU Supporting Member

    Apex makes it easy to have staggered dosing over whatever time period you want. Just set the 2 timeframes to start a minute offset.

    I’m not convinced there is a good scientific reason to dose over certain intervals vs others, 2 parts staggered vs separated by half a day, day vs night vs 24 hours. 2-part dosing doesn’t have much of an effect on pH and the effect it has is very transient. I think the only really important thing is consistent daily dosing, and probably the more spread out the better.

    Maureen you should tell admin that smaller class sizes would be better for the pH of the reef tanks. :)


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  8. MolaMola

    MolaMola Supporting Member

    Now that is a brilliant idea.
     
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  9. Schmitty

    Schmitty Supporting Member

    When I add 7.5 ml of alk it definitely raises my Ph...
     
  10. JVU

    JVU Supporting Member

    For sure, but by how much and for how long? Divide both of those numbers by 24 or 12 to see approximately how much the pH would rise and for how long if the dose was a split up to once an hour for 24 hours, or for once an hour at night. Actually, Apex will likely dose more often than once an hour, making the impact even smaller, depending on the total volume. It always goes back pretty quickly to the baseline pH curve set mostly by CO2. If we are mimicking the ocean, presumably spikes in pH once or twice a day aren’t good and smooth curves are better.


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