so assuming I get a Calcium reactor to keep my system balanced out. What do you look for in one?

How is this one:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2 0758&item=4319334586

Or an 'electronic' one?

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=2 0756&item=4321610587&rd=1&ssPageName=WDVW

Well I know that when your alkalinity is high, you add Calcium to lower it and that affects PH as well, but is it really safe to control all those levels just from your calcium input?

Calcium and alkalinity (for this discussion I will refer to alkalinity as carbonate) are two independant entities.  They are like teenage boys and girls.  They're different, but constantly looking to hook up together .  Calcium reacts with carbonate (CO3) to form CaCO3 coral skeleton, coralline algae, or "hard water deposits".  It just so happens that the pH of seawater is more or less controlled by the carbonates (both the amount and type) floating around in it (for reasons I'll discuss, but might cloud the issue).  If you remove carbonates (coral growth, ect) from the water the pH will drop.  If you add carbonates (buffer) to the water the pH will increase.  Both calcium reactors and kalkwasser add equal amounts of calcium and carbonates to the water (i.e. balanced).  If you have a steady, constant amount of carbonates in the water you'll most likely have a more steady pH.

The reason why adding extra calcium lowers alkalinity is because that extra calcium reacts with the carbonates and is precipitated out of solution as CaCO3.  This then lowers the pH.

Mark Peterson wrote: Pat, you don't have enough hard coral to worry about a Ca Reactor.

but I will

I'm finishing my canopy this week and will have 3-250 MHs and 2 6' VHO actinics. I plan on starting to get some real coral now.

Already have the automatic top-off system installed with the 6 stage RO filter and float valve, so I'd need another solution, even if it's Kalk and a IV pump adding specific amounts regularly.

jfinch wrote: Pat,  what does "balance alkalinity and pH" mean to you?

Well I know that when your alkalinity is high, you add Calcium to lower it and that affects PH as well, but is it really safe to control all those levels just from your calcium input?

I guess I don't understand how tightly they affect one another.

I knew extra calcium would lower alkalinity, but I didn't know it that it was a direct relation. So does a calcium reactor really handle ALL your problems (assuming it's eventually adjusted correctly)?

Pat,  what does "balance alkalinity and pH" mean to you?  We might be able to explain better if we know where you're coming from.

Yea, I've seen it. but I've also seen the price sticker. If I can't find another way, I'll save up for one.

One thing though, I didn't think a Calcium reactor would balance alkalinity and PH, just calcium, strontium....