Throwing powdered chem into sump

[marietrg]

Working with Calcion-P and Alklakin8.3-P from brightwell. Why not just throw the powder into the sump? Why dissolve in H2O first? Any downsides to this?

[thegrun]

Yes it needs to be diluted with pure RO/DI water. Putting it straight in the saltwater creates a momentary over concentrated area of additive, where it will react with the saltwater and form calcium carbonate. There isn't anything wrong with making calcium carbonate (well, it may cloud your water a little), but doing so basically removes the alkalinity or calcium from the water column which defeats the purpose of putting it in your tank in the first place. Even with the solution mixed in water it is best to add it slowly, I drip it at about one drop per second.