Calc, Alk, & Reactor

[Mescalito]

Randy,
Before I begin let me say thank you for all your past help, it has been invaluable to my critters.
Last week you helped me with my low salinity situaton. Salinity is now up to 34 and I am still adding salt mix to my top-off water until I reach 35.
The question I have today has to do with Alk, Calc, & Reactor media. Alk reading 14.7, Calc reading 350. I need to get these to their proper levels, 11 and 450. After entering them into my log I see that Jan. 28 is the date I have enterd to change my calcium reactor media (six months). Could the depletion of the media's effectiveness contribute to the readings I got today? I also dose Kalkwasser (ESV) with my top-off and my reactor is a dual chamber. Any insight you can offer would be greatly appreciated.
Thank You,
Jeff

[Randy Holmes-Farley]

Could the depletion of the media's effectiveness contribute to the readings I got today?

No.

More likely is the following:

If you start with a salt mix like Instant Ocean at S=35, alkalinity = 2.3 meq/L and calcium = 360 ppm from this article:


http://www.animalnetwork.com/fish2/a.../1/default.asp

If you then try to raise the calcium to 450 ppm using any balanced additive system (the B-ionic, a CaCO3/CO2 reactor, limewater, etc) then the alkalinity would necessarily be pushed to 6.8 meq/L (19 dKH)!!!!!

That's because for every 20 ppm rise in calcium, alkalinity will rise by 1 meq/L (2.8 dKH).

So if you want to bring up calcium, and not bring up alkalinity (or even bring it down), you need to add a calcium only supplement, like Kent's Turbo calcium, or Saliferts Coral Calcium.

Here's an article that details how to make such adjustments to calcium and alkalinity:

http://www.advancedaquarist.com/issues/nov2002/chem.htm

Before I begin let me say thank you for all your past help,

You're welcome!

[yaktop]

if seawater is 410 ca and 2.5 alk why do people try all sorts of variations? arent we supposed to mimic nature?

Randy I am dialing in my first dual reactor and quite confused with all the 'variations'. right now I am 380 (low) and 11

I read some tanks at around this others say my alk should be in the 3's and my ca will take care of it self - or add if you have alot of sps.

whats the best short answer you can give me.

thx,

ed

[Randy Holmes-Farley]

and 11

Let's make sure we are talking about the same units.

I presume that 11 is dKH, which is equivalent to 4 meq/L alkalinity. I recommend folks keep alkalinity at 7-11 dKH which is 2.5-4 meq/L.

So I assess that you might want to raise calcium a little bit (into the 400's) with a calcium additive, like calcium chloride.

if seawater is 410 ca and 2.5 alk why do people try all sorts of variations? arent we supposed to mimic nature?

Many people have alkalinity higher than 2.5 meq/L for one of several reasons:

1. They claim that growth of calcifying corals is faster at higher alkalinity (could be true)

2. In order to prevent the alkalinity from dropping below 2.5 meq/L between additions, the average level must be maintained higher than that.

3. Higher alkalinity results in a smaller pH swings. This issue might be especially important for those using CaCO3/CO2 reactors that often drive tanks to undesirably low pH values.

4. Higher alkalinity also has a general tendency to raise pH , which can be important for CaCO3/CO2 reactor users.

All of these reasons make some sense to me, and I usually recommend alkalinity be kept between 2.5 and 4 meq/L.

[yaktop]

thanks alot.

[Randy Holmes-Farley]

You're welcome.