Where to dose in a continuous wc system

[morphriz]

Hi all,

I'm setting up continuous waterchanges in my SPS nano using dosing pumps. I've had some thoughts about how to do my dosing of Ca and Alk. The system will change about 5-10% daily which is good enough for exports but not to sustain the Ca and Alk drain. Currently I'm dosing Randy's two-part.

My plan is to calculate my Ca and alk drain and dose up the inflow fresh saltwater to the level required to sustain the tank. This and using kalkwasser for top-off should keep the tank going.

My questions are:

1/ What should I dose into the inflow fresh saltwater
My alternatives so far is two-part or dripping calc overnight before I add a new batch

2/ Has anyone tried a dosing regiment like this? Results?

I also plan to do all other inorganic dosing into the inflow water. Mg, I, Si and so on when needed. Foodstuffs being the only thing that goes into the tank water system.

cheers,
Mattias

[Randy Holmes-Farley]

I do not think that putting them into the new salt water is a good idea. Calcium and alkalinity will get too high and risk precipitation of calcium carbonate.

For example, if you change 1% daily, and want to boost tank alkalinity by 0.5 meq/L (1.4 dKH), the alkalinity in the new salt water would have to be boosted by 50 meq/L (140 dKH). That's never going to fly.

If you change 1% daily, and want to boost tank calcium by 10 ppm, the alkalinity in the new salt water would have to be boosted by 1000 ppm. That's not a good idea either.