The Reef Tank banner

1 - 4 of 4 Posts

·
BRW member
Joined
·
2,610 Posts
Discussion Starter · #1 ·
I was chatting with one of the lfs guys. He is a real minimalist, doesnt even run skimmers on the tank, much less reactors and whatnot. Anyways he was asking me what kind of calcium in in natural seawater. I was like, duh, I don't know. He said Calcium Chloride (makes sense to me!) and then he asked what kind of calcium is used in kalkwasser, (again, duhh....and a blank stare from me) and he said calcium hydroxide (I think that's why he said), and he even mentioned another form of calcium that people typically dose (I can't remember). So anyways. Is there a discussion somewhere about the different ways we dose ca in our systems and the pros and cons of each? Thanks.
 

·
Shark...fish are friends
Joined
·
5,096 Posts
haven't seen a thread, but from what I have read there really doesn't seem to be a big need for dosing calcium if you are using a good salt. Maybe if you have a ton of LPS/SPS or something you might need to, but so far in my experience just doing a weekly water change with reef crystals has been keeping me in the 440ish range on my calcium which seems good from what I've read so far...
 

·
Aquatic Philosopher
Joined
·
15,434 Posts
"Free" (Ca^2+) calcium is rare since it is a alkaline earth metal so it will be with something else if it has a chance. Often in seawater it is paired with Chloride. Mostly because Ca is the 5th most common element and Cl is 2nd. Keep in mind, our corals and rock are calcium carbonate... and there is likely some CaCO3 around too.

As for our tank, the type of Ca added is much more important than the Ca that is there. Sure, CaCl is the most common, but when organisms use Ca they do not use Cl. So Calcium Chloride is not the best supplement because it add Cl that is useless. Same goes with adding baking soda (Sodium Bicarbonate) since sodium is not used. So adding two-part without massive water changes results in Cl and Na an surplus... NaCl (common table salt) then turns the sea water into a brine solution.... definitely not a good thing).

Now with Kalkwasser (Kalk) Ca(OH)2 , things are different. Basically the Kalk is not "stable" (for the sake of explanation) so when Kalk is mixed into freshwater, things change. It reacts with ambient CO2 in water and creates both a source of calcium carbonate and... water.

Here is kalk in water: Ca(OH)2(aq) + CO2(g) -> CaCO3(s) + H2O(l)

So, if corals are using Ca and Co3(carbonate) and not using sodium and chloride... which do you think is better in the long-term of the tank's health.


I don't know about this LFS guy. I like minimalism in tanks. Simplify and add lightness... and all that jazz. But the no-skimmer without a good reason seems to me that this guy might be a mis-information type of guy so be careful... especially if he goes on about which type of Ca is "best" in the tank because most organisms do not care for as long as it is in solution. It is the type of Ca going into our tanks that is the important part. Ask for equations.
 

·
BRW member
Joined
·
2,610 Posts
Discussion Starter · #4 ·
I wouldn't dare ask for equations because I don't follow the equation you wrote above and wouldn't know what I'm looking at anyways lol! But I appreciate your thoroughness.

to answer the question, kalkwasswer, is the right answer?

I've seen his tanks and they look beautiful so he must be doing something right. Not that I plan on running my tank without a skimmer for any length of time ;)

I might print your post out though and take it with me next time to see if he has an answer though. The only thing is I don't want to look like I'm starting an argument cuz you know how defensive people can get when defending why they do things. What do you think? let it go, or ask?
 
1 - 4 of 4 Posts
Top