kalk question

[don-n-sa]

Is there any reason why I shouldn't add kalk strait into the water in my 30g topoff container? I could just put a power head in there on a timer to stir it up a few times a day right?

Other than shortening the life of the tunze pump, any other reason why I shouldn't do this?

[matt]

Yep, you can do it, and you don't even need to stir it up other than once when you put it in. There's some disagreement over whether exposure to air will weaken the KW as it reacts with CO2 in the air. I suspect it might trash your pump, but I'm not sure about that.

There are lots of reefkeepers that just stir kalk into their top off containers and use a peristaltic dosing pump to deliver it to the tank. The advantage of the dosing pump is that the KW never touches the pump, only the tubing.

One other thing is that KW can attack plastic containers; I found that out the hard way when I used to use plastic 5 gallon water jugs to store KW. Acrylic and glass would be fine, though.

[don-n-sa]

Thanks Matt for the great input!

It is an acrylic container so no worries there, the pump for the osmolator is fairly cheap so I wouldn't be adverse to replacing it once or twice a year.

Next question. :)

What is the best way in finding out how much kalk to add to the 30g container? At least to start off with. Also I am used to adding water a few times a week since I use over 30g in a seven day period. Now that I am thinking about adding kalk then I am guessing that I should let it run all the way down, and dose kalk when I fill it.

Also you say that I do not need to have a power head in there to keep it stirred? Why do most reactors have the pump to keep the kalk mixed up[?

[GaryP]

Just add as much as you want. Kalk is only 3% soluble in RO water. The 3% will dissolve and any remaining excess material will just settle to the bottom. The next time you fill the container it will dissolve a little more. This will continue until it is used up and there is only insoluble material left over. This is basically what I do with a 2.5 gal. dosing jug. You need a container with some space below the outlet for the excess material to settle.

[don-n-sa]

So what you are saying is that it does not matter how much kalk that I dump in there? That the water will only absorb so much and the rest will just settle at the bottom? So I should buy a good size container of kalk and dump it in at once and watch it dissovle over time and then add more as needed?

[GaryP]

That'll work. I add 4-5 tablespoons to my 2.5 gal. container every couple of weeks. Just as long as it settles below the outlet, it should be oK. I take a wooden spoon and stir mine up when I add water.

[don-n-sa]

so why have I been looking into buying a kalk reactor???

What am I missing? This seems to be too easy.

[GaryP]

A kalk reactor is probably more efficient in that it can dose several times per day. However, most people don't have the large top off system that you do.

BTW, I don't use a dosing pump. I just drip it in.

[Bill S]

My storage/top off tank is polyethelene. Thoughts on that for Kalk?

[matt]

Bill, I don't know about that. You can try it, but I know from experience that it will destroy the plastic water jugs we often use.

Don, the advantages of a kalk reactor are:

1. All the KW is kept in a sealed container; it never has air contact, is periodically stirred, and thus remains at full strength; usually you're dripping KW from a reactor that is more than saturated; there are some particles in suspension. The ph is really high, and my guess is that it's providing more calcium and carbonate to your tank than KW from a large still container. Stirring in an unsealed container is thought to actually weaken the KW because it increases it's exposure to air.

2. It's very convenient; you can dump alot of kalk in the reactor and you're constantly pushing new fresh water through it. Probably with my reactor and my tank size I could put a month's worth at least in the reactor and forget it. As far as dumping alot of kalk in your top off container and then just pouring more water in periodically, I wouldn't recommend it. Probably it's better to just stir in a tablespoon or so of kalk powder per gallon and let it settle; when it's empty just dump out the remaining slurry (there shouldn't be that much) and start over. At least that's what most people seem to do...there's some thought that the slurry at the bottom will have precipitates of metals that may be in both your water and in the kalk powder. That's one advantage over a kalkreactor, in which case you do not ever have any slurry to discard.

3. Because you're pushing fresh water into the reactor, the tubing and pump never touch KW; only the tubing that exits the reactor. This means your peristaltic tubing will never clog and it's very easy to automate and rely on the dosing accurately. The reactors I make use a sponge to keep kalk powder out of the stirring pump, and i use the little pan world which is pretty reliable and KW resistant. Gator ran his for a long time, never cleaned the pump, tore down the system, sold it to Felipe who let it sit dry for months without cleaning it and it fired right up.

One thing that Stan, the medical dosing pump guy, does, is put a piece of bubble wrap cut to fit his reservoire to limit air contact. You might try that.

Sorry about the long winded answer, I just bought a dosing pump and have been thinking alot about KW dosing for my new tank.

[don-n-sa]

Sorry about the long winded answer, I just bought a dosing pump and have been thinking alot about KW dosing for my new tank.

apology not necessary Matt, your input is apppreciated. ;)

[Wryknow]

Too much contact with air will weaken the mix over time. mixing it with a pump works just fine, but do it in a closed container (like a rubber maid brute trash can with a lid.)
Also, you can buy lime (Kalk) for a LOT less money on-line as Mrs Wages pickling lime ($3-4/lb shipped) or from Fiesta Mart, where it is labelled as Cal Mexicana ($.99 for 4oz.) Both of these are food grade limes and have much higher regulatory requirements than what wholesalers are selling as Kalk mixes.

[beareef19]

or you can read this link and get all your questions answered


http://www.reefkeeping.com/issues/2006-02/rhf/index.php


Barry

[mathias]

whats wrong with just adding a lil to my sump?

[Wryknow]

Adding directly to your sump wil work as long as it's just a little bit in relation to the water volume (maybe 1 tsp at a time per 100 gallons would be safe IMHO.) Kalk will raise the Ph pretty dramatically - especially in the localizewd area that it is added. Also, one of the advantages of pre-mixing is that any heavy metal impurities will have a chance to settle and you can discard the sludge at the bottom of the resevoir periodically.

[mathias]

good point....

[GaryP]

whats wrong with just adding a lil to my sump?

1. Adding the straight solid to the tank can cause a large and rapid swing in pH. Not good.

2. Kalk is a very fine powder, like flour, and it will probably end up being sucked into the pump. Unddisolved Kalk powder will basically kill anything it touches. Since it souch a fine powder, its not going to settle in one place and slowly dissolve. It'll probably get blown all over the tank.

3. Adding solid Kalk at one time will cause a localized high pH, high concentration area that will cause scaling. This will have the effect of not adding any calcium and reducing the soluble alkalinity levels. Definitely counter productive. This can also have the effect of causing your skimmer and return pump to scale and seize up and possibly burn up. Scaling always seems to occur in pumps first due to the fact that the pressure change that occurs as you go through the impeller catalyzes scale formation.

4. Your skimmer will probably also go crazy. By adding that much alkali at one time fats go through a chemical reaction called "saponification." Basically, you are making good ole fashioned lye soap.

Other then that, there is nothing wrong with adding Kalk directly to the sump. :)

[matt]

If you're talking about mixing up a slurry in R.O. water, like a teaspoon or so in 1/2 gallon, or even a gallon of water, then pouring a little of that in your sump, it's okay. Probably not the best way to do it...but mixing kalk powder directly in your tank would be bad like Gary said.