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Old 04-10-2007, 05:13 PM   #13
atom
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Originally Posted by bennkhoo View Post
Had follow your intruction before. Shut down the input for 2 days and check the nitrate it was zero.When I let the water drip 1 drop per second the nitrate went up.Shut down ok ,drip went up and regarding about feeding I do put 1ml.volka per day for 3 days. and stop test ok the next 2 days up again. Do you think I should add in deniball with the bioball.
IMO, this is what has happened. Your dymax denitrator is a carbon base type. It requires organic carbon source for the denitrifying bacteria for respiration and growth. An example of such organic carbon is from the dissolved orgainc compound/carbon from the water column but the amount might be too small (very common) to play a crucial role. Another important factor is the presence of dissolved oxygen in the waters and its inhibiting effects. To effect denitrification, the oxygen concentration must be reduced to a level low enough to avoid inhibition or repression of nitrate reductase. Unless dissolved oxygen is removed by chemical addition, the amount of electron donor (organic carbon) added must be equal to that needed to remove the oxygen as well as the nitrate.

To cut the story short, the feeding must be constant n frequent. You can try injecting 0.5 ml of volka every 4 to 6 hourly basis. This can be done with a auto-setup using a timer and a dosing pump. This will be costly too. The easiest method is to use deniball. It is a slow dissolving organic plastic or shall I say ....time release organic carbon ball!

Last edited by atom; 04-10-2007 at 05:21 PM.
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