CaRx Questions for an Idiot like me !

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I am looking at getting a Deltec Calcium Reactor soon (I hope). The chap who I am getting it from assures me I will not need to Kalk etc etc blah blah blah.

I would really appreciate some info here. My understanding of a CaRx is this...
Water is pumped from the sump and dripped back into the sump.
Another pump recirculates the water and the Co2 in the reactor. The Co2 that is injected lowers the PH and dissolves the media releasing Calcium, Strontium(?) and Magnesium. The CaRx also helps keep the alkalinity in check.

BUT if the discharge water has a low PH will that not drop the PH of the tank over time . I normally try and raise the Ca Levels with Kalk and that also helps keep the alk and Ph in check. If I am using the CaRx and that boosts the Ca levels could I still kalk. What affect would this have on the tank ?

Sorry for all the questions but I want to put my mind at ease before i go and splurge a whole lotta cash.

Gavin
 
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Read on a forum about a media called ARM that is meant to contain strontium. Will find it...
 

Alan

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Yor tank will generally run at a lower PH, when my CArx runs my system can dip as low as 7.9 but with no ill effects. You can run kalk at night to raise the ph no problrm. Personally i dont run kalk with the reactor, i am also very scared of kalk reactors, too many sad stories with them.
 
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Do you think it is better just to drip in Kalk with a 5 Litre bottle or something then Alan ? I am also a bit worried about running a Kalk stirrer just incase it decides to go mental and dump 25 Litres of Kalk into the tank.
 

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With my system because the demand is so high i let the CArx run 24/7 and the kalk only at night.
 
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I am looking at getting a Deltec Calcium Reactor soon
Deltec is good :)

...assures me I will not need to Kalk etc etc blah blah blah.
Depending on the pH drop, you probably would have to drip kalk as well.

My understanding of a CaRx is this... Water is pumped from the sump and dripped back into the sump. Another pump recirculates the water and the Co2 in the reactor. The Co2 that is injected lowers the PH and dissolves the media releasing Calcium, Strontium(?) and Magnesium.
It mainly adds calcium and alkalinity, but if you use crushed coral, or add some dolomite sand, it will also add magnesium, and whatever is in the media (sometimes also unwanted pollutants...)

The CaRx also helps keep the alkalinity in check.
Correct. It will add calcium and alkalinity (carbonate/bicarbonate) in a balanced ratio. In other words, it won't be possible to raise either calcium or alkalinity without increasing the other component in the same ratio - exactly the same as dripping kalk.

BUT if the discharge water has a low PH will that not drop the PH of the tank over time . I normally try and raise the Ca Levels with Kalk and that also helps keep the alk and Ph in check. If I am using the CaRx and that boosts the Ca levels could I still kalk. What affect would this have on the tank ?
Yes, as previously stated, it WILL drop the pH, and IME one should strill drip kalk. You will have to "tune" the reactor and the kalk driprate to maintain a stable end result, without adding too much calcium & alkalinity. In other words, you might have to dial back the reactor somewhat, and not add the maximum calcium it might be capable of producing. The following simple test will tell you a lot:

  • Stop your kalk drip, and measure the tank's alkalinity whilst everything is stable (and no additives, kalk, etc. have been added for at least 24 hours).
  • Let the tank run normally for 48 hours without ANY kalk or other additives being added.
  • Measure the alkalinity at the end of the 48 hours.
  • Calculate your tank's total alkalinity consumption (in dKH per day) by dividing the alkalinity drop by 2 (days).
  • Now, once the reactor has been running for some time (I prefer at least 2 days), measure the reactor effluent and use the following calculator to fine tune the system:

Hennie
 

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