Originally Posted by
rastafish
http:///forum/post/2672818
What's the relation of calcium to the DkH reading? the lower the calcium the higher the alkalinity? and finally how can u balance if thats the case?
Typically yes, if you have an very high dKH your calcium level will be low, in major cases you can even have 'calcium fallout' in which the calcium crystallizes into calcium scarbonate, a white powder, and settles along the sandbed, rocks and anything else in the aquarium. Lighter instances occur more frequently and is usually noticed by a 'cloudy' water appearance and usually looks slightly white in color. When this happens calcium combines with carbonate and therefore the calcium cannot be used and absorbed by corals etc.. This occurs when the dKH is high, the higher the dKH the more calcium carbonate is present, therefore lower available calcium is present in the tank water.
Generally you can lower your dKH by doing 1 of 2 things. You can do a series of partial water changes, maybe 15% once or twice a week until your tanks dKH is in good range. The water you add must be RO/DI with a dKH level LESS than what is currently in the tank. Second, you can add CO2 into the water, this can be done by adding water that already has CO2 in it, such as selzer or mineral water which both contain carbon dioxide. Carbon dioxide forms carbonic acid when it is added to water. The acid reduces the buffer. When the buffer falls the dKH is lower. Add small amounts only in the beginning and test your dKh about 15 or so minutes after adding it. In the beginning the difference may not be large but, as you continue to add it, the dKH will drop. Checking is important because as the dKH drops, the effect of the mineral or selzer water will become greater (meaning the pH and the dKH will drop more for the same quantity of such water added). Make sure when using this method that you check your pH and your dKH regularly, at least each time you add the water and more often if you can. This will prevent the dKH from falling too low (and the pH too).
To raise your dKH you can add a 'buffer' such as "Super Buffer" . Maintaining a constant dKH will help stabilize the pH and Ca in the tank.
To raise your calcium you can directly add 'liquid calcium' or 'kalkwasser' (limewater) into the tank. However remember your dKH needs to be within range first to prevent the newly added calcium from becoming calcium carbonate.
...confused yet?
Once you balance out your buffer (dKH) everything else should fall into line on its own (i.e. pH and Calcium). I'm guessing your pH is probably very high too right??
I don't know how I started on this dKH/Ca++ because it has nothing to do with Nitrates!! Anyway how are those looking now? Please update your recent parameters.