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RoTTen2TheCore
06/20/2014, 07:32 PM
No idea how this is possible, but I just added 100 ml of clear kalkwasser solution to my 50 gal reef and my alk dropped by 2dkh!?!
I let the solution stand for 2 days, because that's how long it took to become clear and the foggy junk settle at the bottom, then added 100ml quickly into my tank to raise the ph without altering my calcium and alkalinity to much. Before adding I was at 10dkh, and after adding I am now at 8dkh!
What happened?
Should I add alk to compensate for what I just lost?

Thanks!

bundybear1981
06/20/2014, 08:43 PM
It should raise itself again. You shouldn't dump kalk in your tank that way, it should be added slowly / dripped. You said it took 2 days to settle - this is because your mix has exceeded saturation and the excess settled. Did this also get added to your tank?

RoTTen2TheCore
06/20/2014, 09:02 PM
From my understanding, you only have to add it slowly in order not to raise your ph to high and still add some calcium and alkalinity to your tank. Since I just wanted the ph, and not the calcium and alkalinity, I just tossed it in. Any reason why I shouldn't do this?
I only mixed half a teaspoon in 2 gallons. As per the instructions, this is way under.
I only added the clear solution and not the saturated part at the bottom.

disc1
06/20/2014, 09:07 PM
Kalk has a very very high pH and when you add it quickly it will spike the pH in the tank. That pH spike causes calcium and alkalinity to precipitate out of the water. That's the alkalinity you lost. You lost some calcium with it to although it may not be enough to see on your test kit.

Kalk should always be dripped into the tank to avoid the pH spike that high. You should never just dump kalkwasser into your tank.

RoTTen2TheCore
06/20/2014, 09:13 PM
Hmmm, that makes sense. However, I didn't even get a ph spike, in fact, ph dropped by 0.1

cmcoker
06/20/2014, 09:22 PM
1/2 teaspoon kalk or 2 teaspoons kalk per gallon does not make a huge difference in the pH of the solution you end up with. In my 55g tank, adding more than 60 mls (at once) causes pH to spike above 8.5.
if you are going to use kalk that way, you need to start with smaller volume of kalk and monitor the pH. the pH swings you are going to create using kalk this way, is probably more harmful to your tank than a "low" pH.
I would recommend you read some of Randy's articles on pH and using kalk, before doing anything else. by the way, what did your pH end up at?

RoTTen2TheCore
06/20/2014, 09:33 PM
Yeah I read Randy's articles and they are great. My problem is I am seeing the opposite of what was described in the articles.
It dropped my ph from 7.9 to 7.8.
I did start with 10 ml and no change, added 2 more doses of 10 and still nothing, added the other 60 ml and got the results I mentioned, then stopped there.

bertoni
06/20/2014, 10:28 PM
There might be some issue with test noise, but dumping Kalk into the tank might have caused some temporary local pH effects that caused precipitation. The pH of the whole tank might not change much at all, if that's what happened.

tmz
06/20/2014, 11:52 PM
While it sat for 2 days to settle , was it in a sealed or open container?

RoTTen2TheCore
06/21/2014, 05:44 AM
It was mixed in a jug and I put plastic wrap over the top and made it air tight with an elastic, as I read sore contact can make it less potent.

dkeller_nc
06/21/2014, 07:03 AM
I wouldn't go to the trouble of sealing the kalk from air. While exposure to air will develop a "skin" of calcium carbonate on the surface, that reaction really doesn't deplete very much calcium/alkalinity in the solution, particularly if it's a saturated solution. RHF did some measurements on this here (http://www.reefkeeping.com/issues/2005-01/rhf/), and concluded that in a non-aerated container, the potency of the saturated solution changes very little over the course of a few days.

FWIW, 100mL of kalk solution in 50 gallons of tank water isn't very much, one would expect it to have very little measurable effect on your pH. However, as others noted, dumping it into a relatively un-mixed part of your tank all at once could drastically increase the local pH, and produce a cloud of precipitated calcium carbonate.

There's a better way that's almost free, and I used it for years and years on my 20 gallon nano before I upgraded to an ATO a few months back: a drip jug. All you need is a gallon or 1/2 gallon empty white vinegar jug, a plastic airline valve, some epoxy putty or glue, and a short piece of airline tubing. Simply puncture the jug near the bottom with an icepick or the tip of a knife, force the end of the airline valve into the jug, and coat the joint with epoxy putty.

The next day, add a short piece of airline tubing to the outlet of the air valve, fill the jug with saturated kalkwasser, set the jug over your sump/tank, and adjust the valve to give you a slow drip. The valve/airline will clog with precipitated calcium carbonate over time, but all you need to do to restore pristine operation is pour vinegar into the jug, allow a little to drip out (over your sink, of course, not you tank), and pinch the airline closed with a clothespin. Let it set for a couple of hours, rinse it out, and start using it again.

Simple, easy, and nearly free. ;)

Randy Holmes-Farley
06/21/2014, 07:32 AM
The likely explanation of the original observation is that you didn't add enough to be useful!

When you say you added 100 mL of kalkwasser (too small to be useful, in reality) and then measured the pH and alkalinity after dosing, how much later?

That amount of kalkwasser would have boosted pH instantly by about 0.03 pH units, which you'd never see accurately. Then the pH will do whatever it normally does that time of day in your tank, rise or fall, over the next bit of time until you measure it.

That amount of kalkwasser would have boosted alkalinity instantly by about 0.06 dKH units, which you'd never see accurately. Then the alk will do whatever it normally does, which is typically fall until the next time you dose or measure. How long did you wait before measuring?

tmz
06/21/2014, 12:14 PM
I wouldn't go to the trouble of sealing the kalk from air.

Neither do I ;nor do I recommend it for a still reservoir. But a loosely fitting lid as Randy used in his experiments versus a wide open pan or bucket of it with air movement and water movement is different . I could have asked if it was covered instead of sealed to avoid any confusion. In any case the OP's procedure obviates any concern regarding degradation.When I used a drip bucket , I put the lid on it; now I put the lid on the brute can. Not sure but I doubt the surface film is completely impermeable to CO2.

DiscusHeckel
06/21/2014, 03:40 PM
There's a better way that's almost free, and I used it for years and years on my 20 gallon nano before I upgraded to an ATO a few months back: a drip jug. All you need is a gallon or 1/2 gallon empty white vinegar jug, a plastic airline valve, some epoxy putty or glue, and a short piece of airline tubing. Simply puncture the jug near the bottom with an icepick or the tip of a knife, force the end of the airline valve into the jug, and coat the joint with epoxy putty.

The next day, add a short piece of airline tubing to the outlet of the air valve, fill the jug with saturated kalkwasser, set the jug over your sump/tank, and adjust the valve to give you a slow drip. The valve/airline will clog with precipitated calcium carbonate over time, but all you need to do to restore pristine operation is pour vinegar into the jug, allow a little to drip out (over your sink, of course, not you tank), and pinch the airline closed with a clothespin. Let it set for a couple of hours, rinse it out, and start using it again.

Simple, easy, and nearly free. ;)

I used to dose kalkwasser when I had a nano tank. This is what I used:

http://i444.photobucket.com/albums/qq165/mbozcan/P1010581.jpg

The OP should be able to get it from any reptile shop.

RoTTen2TheCore
06/21/2014, 05:37 PM
The likely explanation of the original observation is that you didn't add enough to be useful!

When you say you added 100 mL of kalkwasser (too small to be useful, in reality) and then measured the pH and alkalinity after dosing, how much later?

That amount of kalkwasser would have boosted pH instantly by about 0.03 pH units, which you'd never see accurately. Then the pH will do whatever it normally does that time of day in your tank, rise or fall, over the next bit of time until you measure it.

That amount of kalkwasser would have boosted alkalinity instantly by about 0.06 dKH units, which you'd never see accurately. Then the alk will do whatever it normally does, which is typically fall until the next time you dose or measure. How long did you wait before measuring?

Randy, I measured it about 2 minutes after pouring in the solution. I tested twice because I could barely believe it. Both times 8dkh.
I know that I added very little, but I was adding a few ml at a time to observe what would happen before adding more. I has another 500ml that I wanted to add, but decided not to after seeing the drop.

I then added some buffer and tested again to see my alk back up to 10 after 30 mins.

Randy Holmes-Farley
06/21/2014, 06:00 PM
So if you want to use kalkwasser, you'll need to add a lot more. Typically 1-2% of the tank volume daily. :)

RoTTen2TheCore
06/21/2014, 07:05 PM
So the drop is normal and due to not enough used and if I used more it would have raised my ph and kept my alk?

Randy Holmes-Farley
06/21/2014, 07:18 PM
Yes, unless the demand is so high that it cannot keep up even if you replace all evaporated water with saturated kalkwasser added slowly. That happens if you have a lot of SPS corals, but in my tank it is all I've ever used. :)

RoTTen2TheCore
06/21/2014, 07:26 PM
Neat! Thanks! ;-)

Randy Holmes-Farley
06/22/2014, 06:07 AM
You're welcome.

Happy Reefing. :)