calcium: hydroxide vs chloride

[reefkprz]

ok lets say you wish to dose caclium, both chemicals will raise calcium. but what are the other impacts of dosing one versus the other for caclium maintinence. and the pro's and cons of either of the two.
I currently use a two part dosing regiment, dosing calcium chloride and seperatly a carbonate solution. to maintain both calcium and carbonate hardness (dKH) generally my calcium is about 450-460 and my dKH is 9-11 depending on when I last dosed.
I am considering using kalkwasser when I finish my upgrade to my 125, some input from both camps of thought on dosing for calcium using either method would be great, like I said earlier pro's cons, effects (aka I have heard kalk boosts PH not just calcium) true false etc. please anyone with more expirience in dosing kalk chip in.

 

[jackri]

Both ways work... it depends what works for you and what's more cost effective. A calcium reactor works for a lot of people too. I personally dose 2 part solution I mix up myself daily just for the fact it makes me pay attention to my tanks closer.
#1 ingredient in saltwater is chloride though followed up by sodium which I found interesting in a read yesterday.

 

[reefkprz]

honestly for me either way is about the same cost, give or take a couple bucks, I am mostly interested in overall parameter impact. like what else hydroxide will affect other than just calcium. if anything.

 

[stanlalee]

big differences. the hydroxide reacts with other ions in the water raising alkalinity in roughly the same ratio a 2 part would. calcium chloride has no effect on alkalinity. calcium hydroxide has a pH of over 12 which can raise tank pH (why many people use it) while calcium chloride has no effect on pH. Most importantly kalk doesn't dissolve well ( 2 tsp per gallon max saturation) and is very limited to how much calcium it can add (not only for the little that can be dissolved but the effects it can have on pH if added to quickly. so you cant add alot and you cant add it quickly). you wont be able to keep up with calcium demands using kalk in your reef (at least not from the pics I've seen. not even close) but you can easily dump the required amount of calcium chloride to keep up with demands however high they are. at best all it can do for you is help keep pH up if thats a problem. did I mention it coats all over the pump or valve used to introduce it and just an overall mess to deal with if you dont have to.

 

[bang guy]

Calcium hydroxide can be used to maintain both Calcium and Alkalinity. The Hydroxide removes CO2 from saltwater so it will also raise PH.
800ppm is about the max amount of calcium you can add to limewater (Calcium hydroxide + Water) so the bottleneck is how much water your tank can evaoprate. Adding Vinegar to the limewater will allow more in the solution but we're still only talking about 1000ppm.
IMO Limewater is excellent for a low consumption reef. For a high consumption reef it works perfect in conjunction with a Calcium reactor because it removes the excess CO2 that the reactor adds.

 

[reefkprz]

great thanks stan and bang thats the kind of info I was looking for.
I probably wont go the kalk rout for now since my reef is fairly high consumption in calcium in terms of evaporation and I dont really have a need to drive up my ph through co2 reduction. though its good to know I can use kalk in if I desire to maintain alk and calcium should I go on vacation by adding it to my topoff resivoir, so I dont have to trouble anyone with a dosing regiment. once I figure the evap rate for the 125 with the dual sump I may go kalk due to faster evap levels, but for now I will stick with my 2 part dosing. thanks a bunch fellers.

 

[natclanwy]

Another issue with dosing large amounts of kalk is it has a tendancy to preicipitate your magnesium out of your tank. I was using kalk on my 55g and I had plenty of evaporation, about 5g every 3 days. So was dosing about 7g of kalk each week to try and maintain my consumption. It kept up with my calcium consumption with no problem but I would still have to dose buffer every other week, then I noticed that my magnesion was dropping faster than I could replentish it with water changes and I was having to add a ton of magnesium to keep my levels up. I have since went back to dosing calcium chloride and baking soda/washing soda to maintain my calcium and alk, and I have not had any more issues with my magnesium levels.

 

[reefkprz]

thanks for that input Nat.

 

[bang guy]

Originally Posted by natclanwy
http:///forum/post/3213280
Another issue with dosing large amounts of kalk is it has a tendancy to preicipitate your magnesium out of your tank.
I can believe that. I have found it can precipitate Phosphate so it's not difficult to believe it could do the same for Magnesium. This is interesting.