View Full Version : Ca Reactors vs Kalkwasser Reactors

08/31/2009, 09:04 PM
Ok, the last part of my tank design that I'm trying to come to grips with is Ca reactors & Kalkwasser reactors. The more I read the less I seem to understand. Can anyone point me to some reading on the subject?

I'm trying to understand the difference between them? Is this a Chevy vs Ford thing or is one 'better' than the other? This is an 'either/or' right? Not a 'both'?

08/31/2009, 09:25 PM
You and me both, brother. Be careful asking a question with the term "better" in it or you attract the flamers.
So far what I've found is that it depends on: the amount of work you want to do to keep it running. (Kalk requires refilling more often), whether you prefer your pH to rise or fall with use, and what kind of kit you want to buy and run($$$). You'll also find there are folks that do dose both mainly to have them counter each other pH-wise.
Sorry if that isn't completely helpful, but wanted you to know that you aren't the only one who is confused by this stuff.

08/31/2009, 09:42 PM
appreciate the answer. I thought I had settled on a Geo 618 Ca reactor but now I may be having second thoughts. How much the system costs is not as important to me as systems which will promote a healthy tank so my animals can thrive as well as systems which are relatively less work intensive. I'm spending a lot of time designing a simple but effective ATO system as well as a water changing system where I have quick connect valves I can tap into to facilitate water changes.

From what I've been able to understand I think the CA reactor is the way to go once you get them dialed in since mine will be connected to my Aqua Controller Jr ...

08/31/2009, 09:53 PM
Ca maintains calcium in the aquarium

Kalkwasser maintains alkalinity

One compliments the other

08/31/2009, 09:58 PM
CaRX and Kalk both maintain both ca and alk.

CaRX uses tank water and CO2 to dissolve media. Kalk is used in your top off and is best used as part of an auto topoff.

I prefer to simply mix the kalk in the ATO reservoir Vs a kalk reactor.

08/31/2009, 10:01 PM
i would dissagree with that noboddi, a calcium reactor when used properly maintains a stable alkalinity, along with calcium, but moreso the alkalinity.

u want to use calcium reactor to keep ur calcium and alkalinity up to par, u can use it to boost ur calcium/alk up aswell. they tend to lower ur ph by co2 injection. kalkwasser is more for maintaining levels in low demand reefs, in a 150gallon sps only tank, kalk wont do much for calc/alk. kalks benefits go far beyond the calcium it contributes, it supposedly optimizes protein skimming by a process called saponification, whatever that means, and it gives a nice ph boost.
they can both be run together. figure out the demands of ur reef, and then make a decision. if u have a kalk reactor u may find urself dosing two part, or adding a calcium reactor for ur levels. a kalk reactor may maintain levels in a low demanding reef, and a little two part ever now and then to boost up. with calcium reactor, u wont need anything else to get ur alk/calc in line, but u may find urself adding a kalk reactor to up ur ph.
honestly, u can always add kalk to ur topoff water too, no real need for a reactor.

09/01/2009, 06:49 PM
thanks all. It sounds like my orginial plan to have a CaRx is still sound with the possibility of either adding kalk via my ATO or with a reactor ...

tangtang clown
09/30/2009, 10:18 AM
I am in the same boat as you, I have never used Kalk or a Calcium Reactor and I am interested in one or the other. I am in the final stages or setting up my 125g tank. All I have left to do is order the lighting and plumb the Closed Loop. I have mainly softies now, but I plan on getting a lot more, including SPS.

Marlin, which route did you decide? How is it working out for you?

09/30/2009, 10:20 AM
My calcium reactor supplies more alkalinity than calcium i would go with a calcium reactor if your tank is 90 + gallons

09/30/2009, 11:01 AM
both maitain calcium and carbonate. calcium reactors cost more up front but are cheaper to run in the long run. Also you can add alot more calcium and alk to a tank with a calcium reactor, kalk can only add so much. Kalk will never add too much of either it seems if you just use it as top off, but if you add too much at once you can shoot your PH way too high and nuke your tank. Thats why I quit using Kalk.

Also a kalk reactor will keep your PH high while a Calcium reactor will generally tend to lower it from the CO2 being introduced.

I'd go with the calcium reactor. If your demand for CA and ALK is high enough to use Kalk, it will eventually be high enough to need a CA reactor. That and its alot harder to ruin a tank with a CA reator.

09/30/2009, 11:33 AM
I use one teaspoon of kalkwasser per gallon of top off water and have it in a brute 34 gallon trashcan with an eheim pump set on a timer to run 15 mins every 4 hours. My alk stays at 8.0-8.5, I also utilize a litermeter 3 to top off, and perform a 3 gallon daily water change using the litermeter 3 also, I have to dose calcium, about 2.5ml a day. I am going to amping up my calcium in my new saltwater bin so i dont dose at all. I think i get more of an advantage doing auto waterchanges, i get more more elements replenished such as magnesium ect., and create cleaner water at the same time. My corals have never looked so good. Its a 250 gallon marineland deep dimension slowly filling up with sps.




tangtang clown
09/30/2009, 11:52 AM
Sure looks good LR23.

09/30/2009, 11:57 AM
Ca maintains calcium in the aquarium

Kalkwasser maintains alkalinity

One compliments the other

Kalk delivers calcium and alkalinity in perfect balance and so does a properly set up calcium reactor.

A calcium reactor will actually keep up with calcium and alkalinity demands. A kalk reactor is incapable of doing so on any well stocked hard coral tank as kalk itself is incapable of doing so.

Kalk reactor is just a supplemental toy to play around with unless your lightly stocked and the little bit of calcium and alk it delivers is adequate.

09/30/2009, 04:40 PM
In an ideal world it would be great to run both together as this should keep the PH really stable, the problem with just using a kalk stirrer on its own is that it is limited by how much evaporation you have, in larger or well stocked tanks this usually does not keep up with calcium demands, obviously you could drip it at a faster rate without connecting to the auto top up but then you are introducing more RO water than would be needed and would cause all other params to shift.
If you have the option of just one I would go with the calcium reactor.

Alternatively look into the balling method, I am thinking of going balling light, a little more complex but once you have it worked out is the best method of keeping water parameters super stable.

09/30/2009, 05:05 PM
I like many struggle with low pH. I'll take any pH boost I can get. I dont use a Kalk reactor. I just mix it in the topoff which is a very simple and effective way to do it. I topoff 24/7 with the Kalk. It only provides ~ 1/2 the ca/alk that I need. I dose 2 part at night for the balance. The 2 part also gives me a bit of a pH boost.

10/01/2009, 11:30 PM
good info all around but i see no direct answer to 'what' each equipment is and why one over the other (if any)...

ca/rx = a container with a argonite base media inside (argonite = what the coral bones are made of.. they are basically dead coral). this container has a pump attach to it to recirculate the water over and over again. The unit also needs a system that injects CO2 into this sealed container (the unit is not actually sealed. it's just a controlled enviornment). Co2 infuses with the water inside this container and drops its Ph, turning it acidic. This acidity in turn melts the argonite media (so it is not liquid coral bones) so that the coral can absorb it and use it to make its own bones. since this is coral skeleton melted.. it added almost all needed and more (both good and bad) additive into the tank, but the main thing we are after is Calcium/alkalinity (aka dkh?). got to add in that calk/rx can lower tank ph. why?? well, since it used acidic water (made by injection of co2) to melt the media, some of this acidity makes it into the main talk when this calk/alk filled solution is introduced into the main talk.

kalkwasser (whether in a kalk reactor in put in a topoff container) is calcium hydroxide (same as pickling lime aka mrs wages). This comes in a dry form and is mixed with fresh water (in out case ro/di top of water for evaporation). This mixer is very basic (as in high ph..11+ i think). Kalkwasser when dosed also added calk/alk in a balanced quantity. Since this mixture is on the basic side, it helps balance/buffer the acidity created by a ca/rx. (acids and basses.)

10/01/2009, 11:43 PM
how on with soem limitation and and advantages of the two...

ca/rx: can add a GOOD amount of ca/alk into a tank as this is based on how acidic you want the ca/rx to run. more acidic = more media melting.. the drawback here is that it can get tricky setting it up to dose the amount you need. Also, if you make it run to acidic, you end up melting all your media too fast and turing it from a hard substance into a mush and that is no good. In the long run (if you run it correctly) it saves u $$$.. but the unit cost a good deal of $$ to start off on. How long will the unit or its components last?? long enough to offset the $$ supposed saved? also more plug to plug in and another equipment to breakdown on you. but then again.. if ou have a tnk with high demand, this may be the better way to go...

Kalkwasser: cheaper to start with and it works. they are easy to use.. just add to you top off water container and mix it for a bit.. only problem here is that you are limited to how much u can add. i think maximum satuated kalkwasser is like 2 tbs per gallon. remember that you only add this as top off... so this limits the calk/alk you can add at a given time. another thig is that you need to add it somewhat slowly. if you add to fast.. the calk and alk will precipitate back into solid form befor the coral can even use it. you will see a crazy white cloud forming ( a little is ok but if you get a BIG white cloud, you added to much too fast).

there are more thing that should be considered and can sway you to chose one or the other but I'm lazy.. not gonna add n e more..

ohh.. and all this info came from the top of my head. I only have experience with kalkwasser in my top off tank. I do own a Ca/rx that i have never set-up and used. I no longer own a tank.. =*( so thats my disclaimer..