Octopus Reverse Flow Calcium Reactor

[kngfisher]

looking at investing in a calcium reactor for my 90gal SPS/LPS tank and was wondering if anyone has any experience with this reactor. I have an octopus skimmer and it works great but just wondering if thier calcium reactor is as good as the Precision Marine Calcium Reactor.

 

[Gatortailale]

No experience with octopus. I use a geo calcium reactor.

 

 

 

I found this a good read on how calcium reactor works & making adjustments. If your new to calcium reactors, I advise to read it first before you buy.

 

 

Calcium Carbonate Reactors

Sanjay Joshi: http://www.reefs.org/library/talklog/s_joshi_062997.html

 

 

Adjusting the Reactor (and some reactor Math)

Once you have decided to add a reactor, how do you go about adjusting it, i.e. determining the effluent flow rate and the amount of CO2 to be added.

 

The following discussion is based on several personal conversations with Dr. Craig Bingman, and the experience of several others in the Fishroom.

 

Let us assume that the reef system contains T liters of water. Set the CO2 flow rate to approx. 20-30 bubbles/min and the effluent flow rate to a slow enough drip and let the reactor run for several hours until it reaches a steady state. Measure the effluent flow rate in liters/hr - say its L liters/hr.

 

Now measure the alkalinity in the tank, and the alkalinity of the effluent. The difference between the two values will give you the increase in alkalinity due to the reactor. Let us say this is d meq/L.

 

Assuming no calcification and use of alkalinity, this will result in a an increase in tank alkalinity that is given by the following formula:

 

Increase in tank alk/day due to the reactor = (d x L x 24)/T - (1)

 

Now measure the tank alkalinity after a day. The difference between the increase in alkalinity due to the reactor and the actual increase in alkalinity will give you the daily consumption of alkalinity for your tank. Let us say this value is c meq/L.

 

So now we need to adjust the reactor so that the daily increase due to the reactor is approximately c meq/L. This will give us the setting at which the reactor will replenish the alkalinity that is consumed daily.

 

Looking at the equation (1), we can see that there are 2 ways in this can be achieved.

 

(1) adjusting d - the increase in effluent alkalinity

(2) increasing L - effluent flow rate

The effluent alkalinity can be increased by increasing the amount of CO2, and keeping the effluent flow rate constant. Increasing the flow rate will result in a decrease in effluent alkalinity if the CO2 flow rate is not simultaneously increased.

 

Which one of these is a better adjustment?. My opinion is that increasing the amount of CO2, and keeping the flow rate is a better choice, since it adds less CO2 to the tank.

 

Similarly to reduce the alkalinity of the effluent, it is better to reduce the amount of CO2 added.

 

I don't want to bore you all with the math and chemistry details but I feel that a basic understanding is necessary to avoid the trial and error, and test and adjust solutions. You can use the above equation to calculate, for example, what the value of d should be, given a certain effluent rate and the desired increase in alkalinity - rather than making wild guesses and adjustments.