pH and KH

  1. Archie1208 Member Member

    To keep it short, my pH drops over the course of the week from 7.6 to 6.8-7. Aging the water does not effect it. I have a heavy bio load. My KH is 2 and GH is 11 or 12 (API test kits).

    If this is the norm should I add some crushed coral to filter media to raise the KH - this keeping the pH more stable?

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  2. Archie1208 Member Member

    To add - I am heavily planted and air stones only run at night. Dose with Seachem Flourish and Excel. Lights are T5 HO 6700k (2)and 9000k (2)

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  3. matsungit Well Known Member Member

    Insufficient KH is almost always the cause of pH crashes or fluctuations. This is very dangerous to fish and is a killer. You need a KH of 3 dKH or higher to stabilize pH. Any carbonate compound added to the tank will raise KH. Crushed coral, shells, or cuttlebone have one thing in common. They are bones and bone is made up of mostly calcium carbonate. Your preference will depend on how slow you want the carbonates to dissolve and affect KH. I use sodium bicarbonate which is very fast. Care must be taken when using very soluble carbonates to raise KH as it might cause a rapid upswing in osmotic pressure and harm the fish.

    If you will use baking soda, half a teaspoon till raise 22 gallons 1 dKH.
  4. hampalong Fishlore VIP Member

    Agree with above. Low KH + heavy stocking = pH crash.

    More water changes would also help to replenish it and prevent the pH dropping so much, but stabilising it with a little more carbonate is a better and safer fix. You won't need much, as said already. If you have space, put coral gravel in your filter (not coral sand, this will impede flow). Otherwise I would add a little bicarb when water changing.

  5. Archie1208 Member Member

    Would the cc in the media be a safer way to go? I would think it would be - how much in bag to start? A couple is tablespoons per week to see?

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  6. Thai Aquarium owner Well Known Member Member

    You could also use some small Limestone rocks as tank decor to raise your Kh which is critically low.
    I would not use the baking soda, because just a little can raise the KH and Ph very quickly, so it needs to be added really slowly to the tank if used at all
  7. Archie1208 Member Member

    Is Texas holy rock limestone?

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