jack wrote:For calcium i use purple up few drops of it thats it...
Purple up is Calcium/Aragonite in situ. Here is one of Randy's past posts.
"I do not recommend it for most people.
It is not a useful calcium and alkalinity supplement. The main ingredient, the fine aragonite, cannot dissolve in seawater and is wasted, as I showed here:
Calcium Carbonate as a Supplementhttp://www.advancedaquarist.com/issu...y2002/chem.htm
Other ingredients may or may not be useful.
It disappoints me that so many companies continue to push products with the main or only ingredient being fine aragonite (sand). Either they are ignorant of seawater chemistry, or they don't care that the product doesn't work as described.
I would back off such assertions if any company selling any of these sorts of products could show a single thriving and growing SPS type of tank that could be maintained long term using any dose of Purple Up as the only source of calcium and alkalinity.
The particles of calcium carbonate in Purple up and other products may be so small that they can stay suspended in solution. If they do, they will dissolve during the very low pH part of an alkalinity test, and give a falsely high alkalinity. Calcium kits might also be fooled.
In any case, they will not dissolve in seawater. Some portion of them may dissolve as they get into low pH areas, like deep in a sand bed, just as calcium carbonate sand itself will.
But the water column of a reef aquarium is supersaturated with calcium carbonate, precluding dissolution.
FWIW, I have debated these issues with company reps (like Kent) online here, without ever having them provide any evidence that their product (in that case, Liquid Reactor) is any different than adding fine sand. "