Kalkwasser mixed with saltwater???

Discussion in 'General Discussions and Advice' started by Tobes, 11 Jun 2009.

  1. Tobes

    Tobes Retired Moderator

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    Hi Oom Hennie

    I have a question for the expert :)

    I don't want to add kalkwasser through the RO top up as it's not constant and fluctuates too much between cold and hot days - especially here in KZN with the humidity.
    I know you can mix kalkwasser powder with RO, let it settle for an hour or so, and drip the clear content into the tank under control on a daily basis.

    My question:

    If I put kalkwasser powder in a 2l coke bottle (shake it and let settle), use a small pump to pump from the sump, through the bottle back into the tank by dripping it about 1 drop a second. One can just add a little powder as it gets less.
    Will this work as the kalkwasser is now dissolved in saltwater and not RO?

    Here are some pics

    Pump

    [​IMG]

    Bottle - left is the "IN" with adjustable valve (goes to the bottom) and right is the "OUT" (starts under the cap)

    [​IMG]

    Powder in bottle

    [​IMG]
     
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  3. jacquesb

    jacquesb Retired Moderator

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    HHHMmmmm - very interesting concept Tobes! I am tagging along on this one! (even though I have a CaRX at the moment ;))
     
  4. Tobes

    Tobes Thread Starter Retired Moderator

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    Well, let's hear what Oom Hennie says. If it's not going to work, at least I won't lose anything - maybe a little bit of silicon :p
     
  5. sunburst

    sunburst

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    Tobes/Hennie if i may offer an opinion. The lower the pH the higher calcium solubility. ie Calcium becomes more soluble at lower pH. Does vinegar (slurry method) ring any bells.

    If you are dosing with bi carb or any other alkalinity supplement and your alkalinity is already at premium levels your calcium will quickly be driven from solution. ie calcium additions will be insignificant.

    I would also think that the elevated gas levels in our tanks would precipitate calcium very quickly from your 2 l solution. ie Neutralizing calcium by formin calcium carbonate

    I frequently hear the argument that we cannot control/predict evaporation and therefore calcium/alakalinity additions become inconsistent.... Mmmmmm...This is not true...Yep ,Not true... You do measure alkalinity/cacium once a week. Coincide these measurements with your reservoire top up weekly routine. Just step up, or step down the concentration of your kalk top up, one teaspoon at a time (per 25l) until you find the sweet spot.
     
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  6. Tony

    Tony

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    One can hook a stirrer up to a p.H controller for more accurate dosing of KW and maintaining ones calcium and alkalinity.

    Now for the interesting bit. I have read in a book on marine cemistry that one can use powdered calcium carbonate in a stirrer hooked up to a p.H controller. Kind of a poor mans CARX but it works. The stirrer pump comes on the same time as the pump pushing the salt water through the reactor to keep things saturated as calcium carbonate doesn't dissolve as easily as kalk. The clear liquid is pushed out the top and presto, alkalinity, calcium and magnesium in perfect harmony for four grand
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

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    Hi Tobes

    Good question, but unfortunately I must agree with Sunburst

    I agree with the above. The high pH of the kalk solution will cause both the calcium and magnesium in the salt water to precipitate out of solution, and this will thus reduce the calcium and magnesium content of the water, not raise it.

    IMHO the old-fasioned dripping method is still the best, and safest, method of adding kalk. What I do is to set the drip rate slightly lower than the actual evaporation rate, and have my "auto topup" ballvalve add the "make up" RO water to keep the water level in the sump's pump return chamber at a constant.

    Any additional calcium, alkalinity and/or magnesium is added seperately.

    Hennie
     
  8. viper357

    viper357 Admin MASA Contributor

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    Good question Tobes, if I may piggyback on your thread and ask a question if you don't mind?

    The drip method - I'm lazy so is there anything wrong with using a 25 litre container to drip kalk, if the container dripped for about a month before it was refilled with fresh kalkwasser? Does the mixture get old? Would it need to be circulated occasionally?
     
  9. scubaninja

    scubaninja

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    tobes took you a while to post the question hey:) was a long time ago that we talked about this:) since then my kalk stirrer set up using salt water has been good. it worked brilliantly until the input pipe at the bottom was above the powder after all the dissolving, then i had to increase the flow to get the kalk to dissolve. so on the second stirrer the input pipe outlet is submerged constantly in the powder and no such problems yet
    Posted via Mobile Device
     
  10. Alan

    Alan Admin MASA Contributor

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    As stated above it wont work pumping sea water through the bottle as the PH in the bottle is too high and the sea water entering the bottle will actually have the ca and alk precipitate out of the solution.
    Same thing as a snow storm in a display tank when the PH goes too high, just on a much smaller scale.
    Rather use the drip or slurry methods for addition of kalk.
     
  11. Tobes

    Tobes Thread Starter Retired Moderator

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    Thanks a lot Sunburst, Oom Hennie and Alan - will do it with RO like before, just thought it might work. Never thought about the pH issue :p

    Sorry Scuba - it's a no-go :nono: - we have to use it mixed with RO because of the pH.
     
  12. Tobes

    Tobes Thread Starter Retired Moderator

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    Don't mind at all Dean, would also like to know ;) - but I think it would need to be stirred a bit now and then, hence the closed loop pump on a kalkstirrer.
     
  13. Reef Maniac

    Reef Maniac MASA Contributor

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    Kalk does get old if exposed to CO2, and unless you use a wine "papsak" filled with kalkwasser you probably won't get it to work properly in an airtight container. Having said that, Dr. Randy Holmes-Farley did some tests which showed that the kalk solution was still viable after 18 days if kept in a closed trash can (closed, but not air tight...)

    My system consists of continuously replacing the dripped kalk solution with fresh RO water by means of a float valve in the Kalk container, whilst only adding a large "once off" dose of slaked lime powder every two weeks or so. This works fine for the first week to ten days, but the tank pH does drop 'n little by the end of the second week. If your kalk drip rate was low enough that it did not need replenisment with RO water (as I do...) it should not make much difference, and I would guess that you would be able to stretch the "refilling" time to at least three weeks, perhaps even more.

    Hennie
     
  14. sunburst

    sunburst

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    Yea...I believe so...The drip could be serious... you better check with your family GP...Goodluck...Keep us posted:)
    So your nano is the size of a thimble and you live on the North Pole. :)OK I'll play
    Yes. Over time it reacts with co2 to form calcium carbonate and calcium falls out of solution. So how old do you need to be before you cannot get the job done.... How do we check the virulence of your 25 litres. The real litmus test would be the pH. As CO2 reacts with hydroxide and calcium falls from solution the pH begins to drop. (Dr. Randy Holmes-Farley did some tests) Thanks Hennie. So we can see that the CO2 reaction with kalk has being grossly exagerrated by companies and individuals promoting the use of kalk stirrers
    No...CaOH (kalk) is HIGHLY soluble. No mixing required.
     
  15. scubaninja

    scubaninja

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    WELL, as much as i agree with the facts already stated, my setup seems to be working. I spoke with sunburst (shaun) at great length for a while, and i totally agree with the differences in pH. But my setup seems to be working. My calcium is sittin at about 480 (little bit high for my liking) and alk is at 7. Its been maybe 2 weeks since i started using the 2.0 stirrer and the levels are all constant. I try and check my levels(Ca and Alk) every two days or if i get paranoid when ever i have free time. So in my case its working. I'm not sure if there will be a problem after some time with this stirrer or not, but it is working.

    I kind of stumbled onto the idea as a mistake, and thought it was sound cause i had 'seen' it done but later after this thing had been in operation for a week found out i had seen wrong:p

    So i would suggest going the RO way, as its been tried and tested, but now i'm gonna keep my stirrer going this way and decide for myself:thumbup:
     
  16. jacquesb

    jacquesb Retired Moderator

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    SunBurst - you are REALLY HILARIOUS! Thanks man! I just LOVED to read your responses! :)
     
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