Using baking soda for my Alk

Discussion in 'Reef Chemistry by Randy Holmes-Farley' started by BOWHUNTER4250, Mar 8, 2018.

  1. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    well that's what im trying to get at i guess ?? im mixing each batch EXACTLY the same way EVERY TIME so theoretically they should be the same ?? i don't know how much swing im going to get until i measure the Alk the next day and see where its at ? i shouldn't have to keep adjusting dosing amounts with each new batch ?? i would think it should be pretty close so minor adjustments ok but to go from 8.2 up to over 13 doesn't make sense to me ?
     

  2. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    correct , it is slightly weaker so therfore it should not rise as much ? i do have a large amount of coraline growth and a fair amount of hard coral but not much
     
  3. dimo

    dimo Member Build Thread Contributor

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    Based on your display size I'd say 800ml a day is extremely excessive. I'd say start by taking an alk reading, then stop dosing and wait 8 hours and retest to see how much it drops in 8 hours. Then multiply by 3 to get a rough estimate on daily alk usage. Then use an online alkalinity calculator to determine how much you should dose.

    You're probably mixing the gallon jug correctly. Adding RODI to your dosing container to dilute is what is messing you up. Don't dilute it at all. If alkalinity rises too much, dose less.
     
  4. Jerett83

    Jerett83 Member

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    This right here is what is what you need to do. Your not mixing them the exact same because you said your adding RO to your dosing container to dilute it down to maintain your target DKH at your current dosing rate.
     
  5. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    regardless of the amount im adding i can adjust the dosing amount to get where i want to be ideally on a daily basis , i get that but my overall question is WHY is this happening ? something is happening with each new batch that is making my solution stronger in a sense that it is making my Alk rise ? it would take a few days to re adjust the swing and then im up and down again until it stabilizes ? all of these solutions are after the fact ? what is happening from batch to batch that is giving me such a swing ??? everything else afterwards is reaction to the swing , adding R/O water , adjusting the dosing amount etc...... my point is that i shouldn't have to make that big of adjustments to dosing when im mixing the same solution every time ?
     
  6. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    i am mixing them the same way every time , again .......... 1 box of baking soda to 1 gallon of R/O water , mix , let sit then add to my dosing container ............. check my Alk before i add new solution wait 24 hours and check again , if i am higher than yes i have diluted it down .......... nothing different of the way im mixing or adding ?? its only AFTER that the Alk rises
     
  7. dimo

    dimo Member Build Thread Contributor

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    I don't think you're making the solution stronger. I think you're dosing too much.

    If you've play around with the dosing container by adding RO to dilute it because your alk went too high that is the wrong approach. Then at the When you're adding fresh solution to a container that has been altered to get you stable and it still has some remaining solution in the bottom, then you are effectively mixing 2 solutions that are different strengths. 1 being new, and the other that has been diluted.
     
  8. Dennis Cartier

    Dennis Cartier Active Member

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    Hmm, is your dosing container air tight or close to it? If you are baking the soda, and then leaving it exposed to the air, could the CO2 concentration in the solution be rising and weakening the alk solution over time? You mentioned that you are making a new batch every 4 days and the first day the solution seems very strong, and then weaker towards the end of the batch.

    Dennis
     
  9. 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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    CO2 entering won't alter the alkalinity. It will reduce the pH. :)
     
  10. 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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    I think you are making a solution that is quite hard to keep soluble, and perhaps some is precipitating. Check closely

    In my original recipes, there a two methods. You cannot mix them up, and it seems you sort of did.

    http://reefkeeping.com/issues/2006-02/rhf/index.php

    One uses unbaked baking soda. It is much less soluble than baked baking soda, and so it uses only 297 grams of baking soda per gallon. Not a full pound. Maybe you can get a full pound to dissolve, but it is close tot he limit.

    The second recipe uses baked baking soda, starting with 594 grams of baking soda (weighed before baking). It is twice as strong as the one above.

    You used 454 grams of baking soda in a gallon of RO/DI, which is pushing the limit.
     
  11. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    correct , your on the right track , so what can i do to get the 2 solutions to the same concentricity ?
     
  12. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    i am using the baked method , i bake 1 box at 375 deg. for an hour , now im doing 3 at a time in my oven and i try to disolve this as much as possible , after mixing and sitting for a few hours it is clear , i mix it again to make sure everything is mixed as best as i can , then add to my container and yes the conatainer is pretty air tight
     
  13. dimo

    dimo Member Build Thread Contributor

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    My advice is to not try. It's more work than it's worth since both solutions have too much dkh than can be measured confidently. You'll probably never get them to match.

    I would start from scratch if I were you. I would dump out all the solution in the dosing container and clean it out. Fill it with fresh alkalinity solution you made. After that do not alter it in any way. Resist temptation. That way the next time you fill it, you're pouring in solution that's the same. If you're alkalinity rises too much, stop dosing and wait for it to fall naturally to where you want. Then restart dosing at a lower rate daily. Continue this process until the tank stabilizes. Eventually you'll get to a point where dkh won't move and you can simply keep filling dosing container without having to make major adjustments.
     
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  14. slapshot

    slapshot Active Member

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    Go get a cheap digital food scale. It’s acurate and allows exact measurements time to time. Weigh it after you bake it. I don’t trust the box, it can have more moisture one time to the next. When you bake it you’ll have different concentrations
     
  15. rosshamsandwich

    rosshamsandwich Well-Known Member

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    ARe we talking about Arm and Hammer Baking Soda?
     
  16. rosshamsandwich

    rosshamsandwich Well-Known Member

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    [​IMG]
     
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  17. 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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    Yes, that's the thing to use.

    I think weighing after baking is also likely to cause potency differences unless you are very sure you have fully converted it into sodium carbonate.
     
  18. Mike Reef Addict

    Mike Reef Addict Active Member

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    Yes that is how I do it down to the exact gram I useba container and tare it out and weigh 250g I think it is for recipe 2. I look atvreef chemisty a lot like baking it isn't a pinch of this and a pinch of that...
     
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  19. BOWHUNTER4250

    BOWHUNTER4250 Active Member

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    so is it better to use UN baked baking soda to hold a better potency ?
     
  20. 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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    I just mean when to weigh it, which is when potency is determined. I'd weigh from a freshly opened box.
     
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