In my book, dosing pumps and Ca Reactors are not necessities, but can become a convenience with a constantly growing bioload. Maybe we need to know more about the tank. The need for Alk may be greater than we realize:
- Besides SPS coral, what other carbonate building organisms are there, such as
Coralline Algae, other coral(stony and soft), Snails, Tridacna Clams, Vermitid Snails, benthic clams, Feather Duster Worms, Coco Worms, Hermits, Halimeda Algae and other crabs and shrimp?
- What sand, how deep and how old?
- Is there any Carbonate precipitation/crystallization on pumps and/or surfaces?
- Is this tank running carbon dosing? What method?
Some points to note:
- A swing of <1 dKH/day will usually be no problem over the long run. You said it drops 1.5 dKH in less than 24 hours! This is definitely unusual, not only in the degree of change but the value of the morning starting point of 7.5 dKH is a bit low for most tanks.
- An increased volume of Alk and Ca buffering components, like aragonite sand, rock, and just plain saltwater will reduce the dependency on frequent dosing. Think of it as a bank account of Alk and Ca. A larger amount in the bank requires less frequent deposits to keep it above the minimum. I believe this is what is meant by the term "buffering".
- The drop in Carbonate usage with that change in lighting may be only
temporary, but my opinion is that the MH's were causing faster growth.
- I don't know if this helps, but in coral farming, I have manually dosed every other day a weekly total of almost 2 liters of Alk and 2 liters of Ca.
- Commercial Alk products and homemade Alk (made using Soda and soda ash), are balanced additives. These will not affect pH. (It is Kalkwasser that has a high pH which makes it best added at night when tank pH is at it's lowest.)
Aloha
Edited by Mark Peterson - May 27 2014 at 3:52pm