Chasing ALK

Discussion in 'Reef Chemistry by Randy Holmes-Farley' started by shaywood, Apr 14, 2018.

  1. shaywood

    shaywood Active Member

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    I have a Red Sea Reefer with approximately 92 gallons stocked with healthy SPS. CA is 420, pH is 8.03, MAG is 1260. I use a Geo612 reactor which i steady drip keeping chamber at pH of 6.4. I daily dose ALK using 30ml of Randy's recipe 1 part 2 high pH formula.

    While my ALK had been staying steady over 8 its dropping to 6.8 - 7. Does it make sense to increase the dosing to 60 ml's?
     
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  2. Randy Holmes-Farley

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

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    Corals will do fine at 6.8-7 dKH, but raising it a bit is also fine. As corals grow the demand will rise. I'd also add the calcium part or calcium will start to decline.
     
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  3. J. Austin

    J. Austin Member

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    When you notice a change in chemistry, you should be testing more frequently, especially when you increase or decrease dosing. I like to test alk every two days after a dosing pump increase. You might want to run the CaRx a little harder to get more Alk and Cal output. Like Randy said, test Cal to make sure it's not falling too low.
     
  4. O'l Salty

    O'l Salty Active Member

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    I was dosing 4ml per day of alkalinity about 5 months ago in a 40 breeder. It's steadily been going up and now I'm dosing 15ml/day and alkalinity is barley holding steady. The tank is about 16 months old.
     
  5. rsumner

    rsumner Member R2R Supporter

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    I find myself chasing Alk and pH constantly to the point where I would call it an obsession. I'm using Seachem's Reef Carbonate (http://www.seachem.com/reef-carbonate.php) and Seachem's Reef Complete (http://www.seachem.com/reef-carbonate.php) in my Red Sea Reefer 525 (~140gal total system volume and 108gal display). I've got 5 small Acro frags, 5 SPS frags, a Bubble Softie, and two LPS torch's. My goal is to stay at 8.2 to 8.3 PH and an Alk of 8.5, but I'm concerned I'm dosing too much. NOTE: I do have a recent development of Pineapple Sponges that have started to multiply in my display also.

    I can dump 100ml of Carbonate in the tank at 3:45 in the afternoon (raising PH from 8 to 8.3 and Alk from 6.8 to 8.5) and by 7:45 in the evening, PH will be at 8.1 and Alk at 7.8. Are these small SPS frags and pair of LPS corals chewing up this much Alk (or possibly the Sponges) or do I have some sort of imbalance?

    I'm desperately trying to find a dosing schedule for my Neptune DOS that will keep things stable and Net less huge swings.
     
  6. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Tank 365 Partner Member 2018 Article Contributor Build Thread Contributor North Alabama Reef Club

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    If you want to increase stability you can consider many smaller doses throughout the day. If 100mL per day is keeping your Alk where you want it day to day, try dosing 2mL at a time, 50 times a day.
     
  7. rsumner

    rsumner Member R2R Supporter

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    Thanks, @Brew12. I'm cool with dosing more frequently throughout the day, but is around 150mL a day of Alk normal consumption? I've OD'ed on Calcium before with my DOS and I'm a little gun shy to set auto-dosing that high.
     
  8. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Tank 365 Partner Member 2018 Article Contributor Build Thread Contributor North Alabama Reef Club

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    That does sound like way more than you should need to dose. Do you have any signs of precipitation? How far apart are you dosing the alk and calc?

    I would also advise to not worry about pH. And I definitely wouldn't use an alk supplement to try and maintain it. For a constant alkalinity the only thing that impacts pH is the CO2 content of the water. Getting more fresh air into your tank room or using a CO2 scrubber on your skimmer are both better methods.

    Another option is to do something similar to what I do. I dose saturated Kalkwasser to replenish Alk and Calc. This also has the effect of raising pH because of its interaction with CO2 in the water. I dose 20mL of fully saturated Kalkwasser 75 times a day. I then use the Alk and Calc 2 part to make up for the rest of my demand.
     
  9. rsumner

    rsumner Member R2R Supporter

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    Prior to the start of this thread, I was dosing Alk at night and Calcium during the day, however most of my tests were done during the day, so that could definitely have something to do with it. I've adjusted my DOS this morning to dose 5mL of Calcium 4 times a day and then Alk all day in between with a 30-45min buffer before and after. I **have** made the mistake in the past of letting the Neptune DOS do the spacing on it's own and that led to massive precipitation. Right now, I don't have a lot of signs of precipitation except a little calcification on the sump walls of my return section where my dosing lines run and in my biopellet reactor (that is ran off my return pump).

    As far as CO2, I'm running a BRS CO2 scrubber to help with CO2 levels and that definitely helps keep PH over 8 otherwise I would be running around 7.8 consistently. I may take your advise and try some Kalkwasser, but I'll have to hide another DOS and DDR purchase from the wife somehow :-D
     
  10. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Tank 365 Partner Member 2018 Article Contributor Build Thread Contributor North Alabama Reef Club

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    Have you taken a day or 2 with no dosing to see how much your Alk drops?
     
  11. rsumner

    rsumner Member R2R Supporter

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    Unfortunately, I haven't done a great job at doing this with consistent testing, however with my new dosing schedule, I'm testing Alk morning and late evening (before and after work). Man, I can't wait for the Apex Trident to get released!
     
  12. Randy Holmes-Farley

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

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    That's about 1.1 dKH per day. Not especially high, but all at once dosing that boosts the pH a lot will tend to have more abiotic precipitation. Spreading out the dosing, and maybe switching to a lower pH form (bicarbonate) will reduce the demand.
     
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  13. luca1998

    luca1998 Member R2R Supporter

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    I am under the impression that if you use a CARX, you should only have to dose Alk, Ca and Mg until you have the reactor tuned in to your tanks needs? Once you have your levels were you want them, using supplements to achieve this, your reactor is supposed to maintain those levels. Is my impression regarding how a CARX works wrong?
     
  14. Randy Holmes-Farley

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

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    If it is appropriately sized and has an appropriate media in it, that's true.
     
  15. rkpetersen

    rkpetersen walked the sand with the crustaceans R2R Supporter R2R Excellence Award Partner Member 2018

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    That doesn't have to be the case. Letting the Neptune DOS divide up the doses automatically is actually an excellent way to dose alkalinity and calcium extremely evenly throughout the day and night, resulting in no acute pH or alkalinity swings, even with heavy dosing. However, getting it to work perfectly isn't entirely intuitive, and the Neptune documentation and usage recommendations are severely lacking.

    If you set the DOS to dispense a certain amount over 24 hours, it will automatically set the dosing up as many tiny doses spaced evenly. For example, for 44 ml over 24 hours, the DOS will dispense 110 evenly spaced doses of 0.4 ml each. Which is awesome. But, if you're dispensing the same amount of calc and alk, the default setting will have these tiny doses dispensed at exactly the same times. If your two dispenser tubes empty close to each other, this can certainly lead to precipitation. The trick to avoid this happening is to simply offset the Start time (after midnight) of the dispensing schedule for one component or the other. This is done by clicking the Gear and then Modify Interval on the DOS setup page in Fusion. Set the Start time to 00:05. Now that component will always dispense 5 minutes after the other one. No precipitation.

    If you are dosing different amount of calc and alk with the DOS, the intervals between doses will also likely differ as well, so the risk of precipitation should be low right off. However I still use a Start time offset for one of the components in this situation as well.
     
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  16. rkpetersen

    rkpetersen walked the sand with the crustaceans R2R Supporter R2R Excellence Award Partner Member 2018

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    I've found that the trifecta of two-part, kalkwasser, and CO2 scrubbing is finally keeping my crowded tank in the sweet spot as far as both alk and pH.

    There are different ways to do kalk. I run mine with the ATO but I don't put kalk directly in the ATO reservoir; it goes in a small kalk reactor with stirrer. The reactor is both neater and more effective. With the addition of kalk to the ATO system, I also placed a solenoid valve in line to act as a failsafe against any kind of accidental excess kalk discharge.

    With CO2 scrubbing, I found that I only need do it at night. This keeps my pH from going too high during the day, keeps CO2 available for photosynthesis during the day, and reduces how fast I go through soda lime. Changeover in the morning and evening is automated with a motorized valve on the skimmer's incoming air line.
     
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