MammothReefer
Active member
When it comes to the Recirculation pump on a calcium reactor Should I be.. Pushing water Up threw the media.. or down threw the media.. and does it matter?
Random Calc Reactor Question.
- Thread starter MammothReefer
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TurboDeath
In Memoriam
You should be pushing water to the reactor with the pump.
MammothReefer
Active member
um..
jdieck
New member
Re: Random Calc Reactor Question.
As the media dissolves small particles are left till they creaste some muddy residue, the lower the PH the faster this muddy residue forms.
With an upflow that residue will stit will not tend to plug the flow to the recirculation but it has the disadvantage that particles can be carried over into the pump impeller creating some erosion and into the tank. Because those fine particles have been stripped to basically bare calcium carbonatesurfaces when getting into the aquarium they may promote precipitation of some calcium and alkalinity on the surface, those particles may also skew the alkalinity tests made of the effluent aas they dissolve during tritration making the reading a lot higher than it really is.
On the other hand a downflow as it is forced into a foam pad filter less particless will pass to the pump and thus less to teh tank but as the media will exert more resistance to flow as mud starts to form they may require a larger recirculation pump.
There are ways to make each method work better.
An upflow with a second chamber not only improves the discharge PH and saturation but also the media in the second chamber acts like a filter to those particles. Smaller media (like ARM) will tend to maintain the performance over a longer time on an upflow reactor as in a downflow will tend to plug the chamber faster but the pump has to be sizes as not to create such a large flow as to carry over large pieces of gravel media that can damage the pump.
Some reactors like the Deltec is an upflow reactor that uses very small media,(basically coarse sand) and has an adjustment valve to control the recirculation flow as to actually fluidize the media.
Note that in single chamber reactors with upflow the effluent valve has to be installed at the inlet to prevent being plugged.
A downflow reactor will maintain its performance for a longer period of time with the use of larger media and has the advantage to be able to install the effluent valve at the reactor's ouput. This can alow for some pressure to build up in the reactor which improves the way CO2 is being used but there are other strange effects regarding CO2 and saturation. See, the higher the pressure the faster and the more CO2 can be dissolved in the water without creating bubbles. Using large media in a downflow reactor creates so little pressure drop that actually you will have less pressure at the side of the pump discharge (the top) than at the point of pump inlet (the bottom). This lower pressure on top of the reactor makes the CO2 injected by the pump to bubble out of solution so forming CO2 bubbles on top of the reactor.
This can be solved by using a recirculation line from the top of the reactor back to the pump inlet, this line will capture the CO2 bubbles and recirculate them back into the system.
The other solution is to use about 1 inch of small media on the bottom of the larger sized media as to create a region of higher pressure in the chamber above the pump suction.
Finally for a second chamber because the flow is very small and the chances of carry over are small, IMO it is always better to use upflow and for additional area of exposure to use smaller media that disolves at a higher PH (Like ARM)
So in summary,
Upflow gets better flow distribution for a longer time as it does not plug but may carry over particles and require in single chambers to install the effluent valve at the inlet.
Downflow plugs faster but allows for larger pumps to be used thus increasing the turnover, contact time and on single chambers alow the installation of the effluent valve at the outlet to increase the pressure inside the reactor.
If you use downflow in the first chamber my recommendation will be to use one or two inches of small media topped with larger sized media like Gen-X and then use ARM on upflow for the second chamber. Also to use a CO2 recirculation line from the top of the chamber to the inlet of the recirculation pump.
If you use upflow for the first chamber you can use either large or smaller media and use smaller media in the second chamber.
Finally if you use upflow in a single chamber reactor to improve flow distribution I would recommend to install the effluent valve at the inlet of the reactor rather than the outlet were it can be plugged by carry over particles. .
It works both ways although there are subtle differences.
As the media dissolves small particles are left till they creaste some muddy residue, the lower the PH the faster this muddy residue forms.
With an upflow that residue will stit will not tend to plug the flow to the recirculation but it has the disadvantage that particles can be carried over into the pump impeller creating some erosion and into the tank. Because those fine particles have been stripped to basically bare calcium carbonatesurfaces when getting into the aquarium they may promote precipitation of some calcium and alkalinity on the surface, those particles may also skew the alkalinity tests made of the effluent aas they dissolve during tritration making the reading a lot higher than it really is.
On the other hand a downflow as it is forced into a foam pad filter less particless will pass to the pump and thus less to teh tank but as the media will exert more resistance to flow as mud starts to form they may require a larger recirculation pump.
There are ways to make each method work better.
An upflow with a second chamber not only improves the discharge PH and saturation but also the media in the second chamber acts like a filter to those particles. Smaller media (like ARM) will tend to maintain the performance over a longer time on an upflow reactor as in a downflow will tend to plug the chamber faster but the pump has to be sizes as not to create such a large flow as to carry over large pieces of gravel media that can damage the pump.
Some reactors like the Deltec is an upflow reactor that uses very small media,(basically coarse sand) and has an adjustment valve to control the recirculation flow as to actually fluidize the media.
Note that in single chamber reactors with upflow the effluent valve has to be installed at the inlet to prevent being plugged.
A downflow reactor will maintain its performance for a longer period of time with the use of larger media and has the advantage to be able to install the effluent valve at the reactor's ouput. This can alow for some pressure to build up in the reactor which improves the way CO2 is being used but there are other strange effects regarding CO2 and saturation. See, the higher the pressure the faster and the more CO2 can be dissolved in the water without creating bubbles. Using large media in a downflow reactor creates so little pressure drop that actually you will have less pressure at the side of the pump discharge (the top) than at the point of pump inlet (the bottom). This lower pressure on top of the reactor makes the CO2 injected by the pump to bubble out of solution so forming CO2 bubbles on top of the reactor.
This can be solved by using a recirculation line from the top of the reactor back to the pump inlet, this line will capture the CO2 bubbles and recirculate them back into the system.
The other solution is to use about 1 inch of small media on the bottom of the larger sized media as to create a region of higher pressure in the chamber above the pump suction.
Finally for a second chamber because the flow is very small and the chances of carry over are small, IMO it is always better to use upflow and for additional area of exposure to use smaller media that disolves at a higher PH (Like ARM)
So in summary,
Upflow gets better flow distribution for a longer time as it does not plug but may carry over particles and require in single chambers to install the effluent valve at the inlet.
Downflow plugs faster but allows for larger pumps to be used thus increasing the turnover, contact time and on single chambers alow the installation of the effluent valve at the outlet to increase the pressure inside the reactor.
If you use downflow in the first chamber my recommendation will be to use one or two inches of small media topped with larger sized media like Gen-X and then use ARM on upflow for the second chamber. Also to use a CO2 recirculation line from the top of the chamber to the inlet of the recirculation pump.
If you use upflow for the first chamber you can use either large or smaller media and use smaller media in the second chamber.
Finally if you use upflow in a single chamber reactor to improve flow distribution I would recommend to install the effluent valve at the inlet of the reactor rather than the outlet were it can be plugged by carry over particles. .
