High Alk

Discussion in 'Water Chemistry' started by Reefboi, Aug 8, 2008.

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  1. Reefboi

    Reefboi Astrea Snail

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    Hi... I have a very High ALK in my tank. How can I lower those levels to 2.5 into normal range? On the test kit it explains how to raise the Alkalinity but it doesn't mention anything about how to lower it if it is very high like in my case.
    -tx
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  3. Bogie

    Bogie Snowflake Eel

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    Water changes will dilute any levels too high in your tank.
  4. missionsix

    missionsix Super Moderator Staff Member

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    What is your mag. testing at?
  5. missionsix

    missionsix Super Moderator Staff Member

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    Referenced,
    This is a great link.
    Reef Aquarium Water Parameters by Randy Holmes-Farley - Reefkeeping.com
    Magnesium
    Magnesium's primary importance is its interaction with the calcium and alkalinity balance in reef aquaria. Seawater and reef aquarium water are always supersaturated with calcium carbonate. That is, the solution's calcium and carbonate levels exceed the amount that the water can hold at equilibrium. How can that be? Magnesium is a big part of the answer. Whenever calcium carbonate begins to precipitate, magnesium binds to the growing surface of the calcium carbonate crystals. The magnesium effectively clogs the crystals' surface so that they no longer look like calcium carbonate, making them unable to attract more calcium and carbonate, so the precipitation stops. Without the magnesium, the abiotic (nonbiological) precipitation of calcium carbonate would likely increase enough to prohibit the maintenance of calcium and alkalinity at natural levels.
    For this reason, I suggest targeting the natural seawater concentration of magnesium: ~1285 ppm. For practical purposes, 1250-1350 ppm is fine, and levels slightly outside that range (1200-1400 ppm) are also likely acceptable. I would not suggest raising magnesium by more than 100 ppm per day, in case the magnesium supplement contains impurities. If you need to raise it by several hundred ppm, spreading the addition over several days will allow you to more accurately reach the target concentration, and might possibly allow the aquarium to handle any impurities that the supplement contains.
    An aquarium's corals and coralline algae can deplete magnesium by incorporating it into their growing calcium carbonate skeletons. Many methods of supplementing calcium and alkalinity may not deliver enough magnesium to maintain it at a normal level. Settled limewater (kalkwasser), in particular, is quite deficient in magnesium. Consequently, magnesium should be measured occasionally, particularly if the aquarium's calcium and alkalinity levels seem difficult to maintain. Aquaria with excessive abiotic precipitation of calcium carbonate on objects such as heaters and pumps might suffer from low magnesium levels (along with high pH, calcium, and alkalinity).
  6. Reefboi

    Reefboi Astrea Snail

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    haha reads about 3.6
  7. missionsix

    missionsix Super Moderator Staff Member

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    Not quite sure what that translates to in ppm.
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  9. Tangster

    Tangster 3reef Sponsor

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    Where did you come up with the idea that 2.5 alk was high ? thats about as low as any form of saltwater can be and keep much alive I run mine 2.5 is about 6 or 7 dkh.. I never let mine fall below 11dkh or 4.25 m/l
  10. Bogie

    Bogie Snowflake Eel

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    And if you don't want to do water changes, FWIW, I think vinegar could be used to bring the Alk down, but like Tanster said, why would you want it lower than 6-7m/l?
  11. Tangster

    Tangster 3reef Sponsor

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    Anytime you feel you have to pull the carbonates down to lower P.H use club soda far more safe then vinegar
  12. missionsix

    missionsix Super Moderator Staff Member

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    How high is your alk/kh?