Calcium Hydroxide vs. Calcium Chloride

[genesis]

So I use the BRS as the supplements for my reef. I use 3 part: calcium, Alk, and mag to dose when needed. Upon initially switching my tank from a FOWLR to a mixed reef I raised all my parameters to the new acceptable ranges. For raising my calcium I used the Calcium Chloride to get it to 440. After getting all my levels to an acceptable range I used Calcium Hydroxide (kalkwasser) in my ATO which does a great job at keeping my parameters stable. For over 6 months I have not had to replenish Calcium levels due to the Kalk, as it stays constant at 440.

Question- Does it effect the corals in any way with the up taking of calcium hydroxide instead of the usual calcium chloride? Is there any difference? Any experience or information please chime in.

 

[genesis]

Info from the BRS website on the supplements I use.

Kalkwasser - This will be used for daily dosing to maintain calcium and alkalinity levels as well as elevate the tanks pH. Because this product does elevate the pH, it is important to dose slowly in small amounts. This product is designed to be used daily to continually replace calcium and alkalinity as it is consumed and not to make large adjustments.

Calcium Chloride - This is used to make larger adjustments to calcium levels. This product has no effect on the tank's pH so it is possible to make larger changes to calcium levels in single doses.

Sodium Bicarbonate - This is used to make larger adjustments to the tank's alkalinity levels. Sodium bicarbonate does have a small temporary lowering effect on the tank's pH. It is possible to make relatively large adjustments to the tank's alkalinity without a major impact on the tank's pH but it is wise to monitor the tank's pH while dosing.

Magnesium Mix - Dosed occasionally to maintain magnesium levels. Maintaining correct magnesium levels helps prevent calcium and alkalinity from precipitating and makes maintaining correct parameters much easier.

 

[russ-iv]

most people i know use calcium chloride and baking soda

 

[crew]

Kalkwasser is basically Calcium Hydroxide, like you already mentioned. Essentially, it's a stable 2-part by itself, because you are dosing like this:

<span style="color: Red">Ca</span><span style="color: Blue">(OH)2</span>

<span style="color: Red">Ca = Calcium</span>
<span style="color: Blue">(OH)2 = Hydroxide, or an Alkaline solution, alkalinity</span>

Kalk isn't a perfect solution, but it's a very good one. It will keep Cal and Alk stable and balanced. The reason for this is sort of simple in the chemistry world. Since the calcium part is basic, we will focus on the hydroxide. While you are adding hydroxide to the tank, it only stays hydroxide for a fraction of time. It quickly reduces into carbonate or bicarbonate and binds with the calcium (calcium carbonate and calcium bicarbonate - what the corals take up) Most of this is a function of it running into the dissolved CO2 in your tank.

When you use 2-part, you are essentially jumping forward to the second step of the kalk process and adding either carbonate or bicarbonate straight to the system. Either way, both are very good ways to keep calcium levels where you want them, but if you need to raise calcium to acceptable levels first, you will want to skip Kalk. The Alk ions are much more prevalent and you won't be able to raise calcium without having a pH issue or spiking alkalinity. Not to say it's impossible, but it would take a lot more effort going this route vs. dosing calcium directly.

 

[reefkeeper]

Been using calcium chloride and baking soda receipt for years in my frag system. Refer to web for Randy's NEW 2 part receipt. He's write up is pretty good..