Question on Kalk

[clowntrigger]

Hi to all

I think the above question may has been address before. But I think I still have not get the right idea of it, so bear with me.

1. Kalk are recomended to be drip via a dripping system, some say at 1 drop a second into the main tank or sump where the current are swift. Some say you could add in to your top up for daily evaporation. Best time to add Kalk is at night as the PH is the lowest.

Question : Currently my evaporation rate for a week is about 6 gallon and I wish to add Kalk to my top up. Problems is every time the top up occurs, there is about 300-400ml of water going into the sump during a duration of 1 minutes. So could I still employ Kalk in this case? The top up occurs the whole days, some say you only add Kalk in the night as the main tank PH is the lowest.

Given the constraints that I have

a. each top up of water is 300-400ml over a period of 1 minutes

b. Approximately about 8 times of top up per day

c. Top up occur in the day and night

can I still add Kalk into the top up resevoir that I have? Take note the Kalk when prepared will need to last from 3-5 days as I top up my reservoir twice a week. Need those with experience with Kalk to comment the above, thanks.

[Tanzy]

You can use kalk and dripping that small amount into your 3' should be ok as long as there is good mixing. What I'll worry about is the kalkwasser going bad. Don't store kalkwasser unless in an airtight container for more than 24 hours. The calcium level drops off sharply the longer it is exposed to carbon dioxide.

[clowntrigger]

Thanks Tanzy, I thought the layer form on the surface of the Kalk water is to prevent it from getting bad? I see that people from RC prepared about 5 days worth of Kalk to be used in their top up, so that is not right as the Kalk will go bad?

[lonaman]

Hi Tanzy,

When you say kalk should not be stored, do you mean it should not be mixed and kept?

The powder can keep right?

[Tanzy]

clowntrigger,

If you can keep it airtight then its fine. The layer is not a membrane, just precipitated calcium carbonate suspended by surface tension. The calcium carbonate crystals will act like seeds and more will precipitate.

lona,

Ja! Just keep it dry.

[lonaman]

Hi Tanzy,

If I'm not into coral, should I still worry about calcium level? I notice it's mostly for coral?..not too sure here..

[Tanzy]

You can be less bothered, but calcium will still be required by coralline algae and snails, etc.

[Joe_P]

For those with auto top up system, why not try DIY a Kalkreactor.... these DIYs are airtight with a stirrer...... activated by a timer a few times a day ..... when the sump volume drops, the auto topup will activate, causing fresh water to enter the Kalkreactor at the bottom causing the Kalkwater to flow out from top into the sump.......

[DragonGoby]

I'll be making a Nilsen reactor in a few months' time - a little busy right now, and I'll have to figure out how to wire and work float switches!

While we're on this subject, could anyone explain why it is always advocated that we dose with saturated kalkwasser, and not a dilute form? Won't a dilute solution have a lower pH and be less harsh when added? One thing I could think of is the addition of as much Ca as possible using a small volume, especially when evaporation rate is too low. Any ideas?

Regards,

Hong Yee

[Tanzy]

Attached is a graph of Calcium ion concentration in solution versus pH. It is obvious looking at the curve that at lower pH towards 7, the Ca concentration is very low. Kalkwasser and calcium hydroxide solutions will always have basic pH that is greater than 7, so the optimum as I have suggested before is about 12.4 for the best saturation of calcium in the kalkwasser.