Two part dosing alk and calcium question

[deepseadan]

Been thinking about this for a while and can't seem to grasp exactly what happens. As I understand it, before you start a dosing, you bring your alk and calcium to the correct levels. After that, you dose calcium and alk ( sodium bicarbonate) at a specific rate to maintain the levels. But here's where I get confused. I thought the reason for dosing cal and alk together was to keep from getting alk / ph swings since calcium chloride will drop alk. But what happens if you slightly over dose to much alk and cal. Will your alk and calcium both rise equally or just your calcium. It makes sense both should rise equally since both are being overdosed a bit, but then again, since they cancel each other out, it also makes sense that the calcium would be the only level that would rise. Can someone straighten out my thinking.

 

[jerpa]

Two part consists of separate alkalinity(sodium bicarbonate or sodium carbonate) and calcium(calcium chloride) solutions. When properly mixed an equal portion of both solutions will contain alkalinity and calcium in the same 5:2 ratio that corals calcify at.

The calcium portion does not normally drop alkalinity and has no effect on PH. The alkalinity will raise PH if you are using sodium carbonate, or soda ash, or will lower PH slightly if you use sodium bicarbonate, or baking soda.

If you overdose both portions alkalinity and calcium will both rise until the levels get so high they can no longer be held in solution. Then you will see the numbers stop rising and will start to see abiotic precipitation as any alkalinity or calcium added quickly turns to calcium carbonate.

 

[disc1]

Been thinking about this for a while and can't seem to grasp exactly what happens. As I understand it, before you start a dosing, you bring your alk and calcium to the correct levels. After that, you dose calcium and alk ( sodium bicarbonate) at a specific rate to maintain the levels. But here's where I get confused. I thought the reason for dosing cal and alk together was to keep from getting alk / ph swings since calcium chloride will drop alk. But what happens if you slightly over dose to much alk and cal. Will your alk and calcium both rise equally or just your calcium. It makes sense both should rise equally since both are being overdosed a bit, but then again, since they cancel each other out, it also makes sense that the calcium would be the only level that would rise. Can someone straighten out my thinking.

The reason you're not understanding is that you have been given a way oversimplified explanation there. Calcium and alk don't cancel each other. Sometimes they'll precipitate if they're too high, but other than that they have no effect on one another.

Go to the Chem board and read some of Randy's articles. They might help to clear things up a little.

 

[deepseadan]

Okay, I've never noticed that section before. Heading over to the chem area.