- Messages
- 1,129
- Reaction score
- 1
... dropped the bubble rate a tad... pH now equals 7.05. I'll PM ya Dave. Or would it be easier for me to post a video? Would probably be Sunday or Monday before I could get it posted on here though.
Calcium Reactor Primer: Theory and Fine Tuning
- Thread starter acroholic
- Start date
-
- Tags
- calcium reactor
- Messages
- 1,129
- Reaction score
- 1
Alright... here's a video of whats goin on. Its an iPhone video so the pic isnt awesome or anything.
And Dave, whenever we can meet up... I'll ask for your infinite wisdom on the plumbing, specifically setting up a manifold.
EDIT:
Okay, I dont know if this forum has settings that prevent video, but I cant get it to work. It shows in my build thread and here is a link:
And Dave, whenever we can meet up... I'll ask for your infinite wisdom on the plumbing, specifically setting up a manifold.
EDIT:
Okay, I dont know if this forum has settings that prevent video, but I cant get it to work. It shows in my build thread and here is a link:
- Messages
- 3,379
- Reaction score
- 4
Dave- one point in this write up- you mention a few times that a calcium reactor will add water rich in calcium, alkalinity, and magnesium. I don't think this is accurate. Most media is simply coral skeleton, which is calcium carbonate. Magnesium will not be supplemented by using a calcium reactor as such. People have attempted to use additional media (rich in magnesium), in addition to calcium carbonate in their reactors to supplement magnesium, but I can't comment on their success. Overall, though, magnesium supplementation cannot be supported by standard calcium reactors, as far as I know.
- Messages
- 3,379
- Reaction score
- 4
A nominal amount. Magnesium supplementation is still necessary.
Actually, I mention this only once in the write up. My use of the term "rich in magnesium" is probably not accurate in the relative amount of magnesium compared to the amount of calcium and bicarbonate released, but in the write up I state that magnesium is not used extensively in the calcium carbonate skeletons of corals, but that its main function is to limit the abiotic precipitation of calcium carbonate in solution. But it is used in coral skeletons to an extent. To quote Randy Holmes Farley:
"Whenever calcium carbonate begins to precipitate, magnesium binds to the growing surface of the calcium carbonate crystals. The magnesium effectively clogs the crystals' surface so that they no longer look like calcium carbonate, making them unable to attract more calcium and carbonate, so the precipitation stops. Without the magnesium, the abiotic (nonbiological) precipitation of calcium carbonate would likely increase enough to prohibit the maintenance of calcium and alkalinity at natural levels"
From the Same Randy Holmes Farley article (bold added):
"An aquarium's corals and coralline algae can deplete magnesium by incorporating it into their growing calcium carbonate skeletons."
Randy's Reef Alchemy article would contradict your point, so dissolving calcium reactor media (coral skeletons) should release the magnesium corals take from the water and incorporate into their skeletons, unless it goes somewhere I am not familiar with besides back into the tank water with the effluent.
CaribSea, manufacturers of the ARM line of calcium reactor media, also print magnesium levels in this media. For example, ARM Extra coarse has 2000 ppm magnesium. ARM extra fine has 1050 ppm magnesium. So I do not believe it is accurate to state that you cannot supplement magnesium through a calcium reactor.
But the above being said, most reefers using calcium reactors are probably supplementing calcium, magnesium and bicarbonates from several additional sources, among them water changes with fresh salt mix, their live rock, and any substrate they use.
My personal experience is that I have not had to add any additional magnesium to my 100 gallon mixed reef, only using a GEO 612 with ARM large media in it. But I also do water changes.
I certainly would not discount any particular situation that would require additional magnesium supplementation in a reef. But magnesium is incorporated into coral skeletons, and when these coral skeletons are dissolved in a calcium reactor as media, the magnesium should be released in the ratio to calcium and bicarbonates it was originally taken up at by the corals.
Referenced Reef Alchemy Series article by Randy Holmes Farley:
A small correction: Apex controllers don't use hysteresis, they use If/Then statements. A pH controller could be used two ways:
1. If pH > xx then ON
In this example, your CO2 would come on at xx PLUS .1, since that is the first value that is above xx.
2. If pH < xx then OFF
In this example, your CO2 would turn off at xx MINUS .1, for the same reason.
My reason for explaining this is that it doesn't float .1 on BOTH sides of the value as hysteresis would. You don't program a high point and a low point; you program one or the other.
- Messages
- 3,379
- Reaction score
- 4
Then, when reactor media that has calcium, bicarbonates, and magnesium in it is dissolved in a calcium reactor, where does the magnesium go? Please tell me how stating it goes back into the water column is a "leap of deductive reasoning"? If not back into the water column in the effluent as the the media is dissolved, then where? Really not too many places for it to go except back into the water column.
Acroporas also utilize light for growth and in the calcification chain. Do they release light when dissolved?
You are comparing the elements that comprise coral skeletons/calcium reactor media with the energy used to drive the reaction? I never went there in that apples to oranges comparison. I'll assume you are being facetious.
- Messages
- 3,379
- Reaction score
- 4
Acroholic;658728 wrote: Then, when reactor media that has calcium, bicarbonates, and magnesium in it is dissolved in a calcium reactor, where does the magnesium go? Please tell me how stating it goes back into the water column is a "leap of deductive reasoning"? If not back into the water column in the effluent as the the media is dissolved, then where? Really not too many places for it to go except back into the water column.
You are comparing the elements that comprise coral skeletons/calcium reactor media with the energy used to drive the reaction? I never went there in that apples to oranges comparison. I'll assume you are being facetious.
Yes, I was poking fun. But, the moral of it is what I was hoping would be seen. Im simply stating just because magnesium is absorbed, and some is deposited on the skeleton (which I dont disagree on), that it does not mean ALL of it is, and is a reversible equation. Do soft corals or non stony corals utilize magnesium? If so, where does it go? What about clams, snails, and others shell depositing organisms?
The "leap of faith" I see is that you are inferring a 1:1 input to output. I dont see that, through practical observation. Thousands of aquarists of the years have needed to supplemental add magnesium in one way shape or form when using calcium reactors. If your suggestions are true, none of them wouldve needed to.
In regards to the labels of ARM media, I think thats a misleading figure, too. I dont have one in front of me, but I would imagine the numbers for calcium and alkalinity are astronomical on them. As I said, Im sure there is a nominal magnesium input, but I dont see it that it is a "total" value, as you are suggesting. Just my opinion.
Your observation that many many reefers have had to supplement magnesium is certainly correct. I've seen that and have done it myself. But does that necessarily mean that magnesium is being used by reef critters in excess of what a calcium reactor can put into the water column? This could easily be explained by salt mixes deficient in magnesium just as it could be explained by usage by shell depositing organisms other than corals. So are we playing magnesium catch up with our salt mix, or is magnesium being used up faster than a calcium reactor can deliver it? I can't answer this one, but each answer seems reasonable. Maybe the answer is both?
Here is an Aquariumwatertesting.com magnesium analysis of 13 major synthetic sea salt brands, and 9 out of 13 brands were below NSW ratings of 1280, let alone the 1350 target range used quite a bit in the hobby. Use any of these brands for water changes over time and you will be adding extra magnesium to correct a deficiency, not from excess consumption by calcium depositing organisms, but from inadequate magnesium in the salt mix to start with.
http://www.aqua-medic.com/aquariumwatertesting/AWT_Salt_Analysis_0208.pdf">http://www.aqua-medic.com/aquariumwatertesting/AWT_Salt_Analysis_0208.pdf</a>
This is speculation on my part, but clams, snails, and others shell depositing organisms lay down calcium carbonate like corals do, so I would guess, but don't know, that the relative ratio of calcium, bicarbonates, and magnesium used is similar to that used by corals, so I would not think it would be hard to meet their demands with a properly dialed in calcium reactor, and that whatever is used by shell depositing animals just depletes the media faster than if just corals were using it.
There may be some additional magnesium supplementation required for some systems, and there may not be, but this could be from low magnesium in salt mixes just as easily as the reason you stated. No reef tank is going to be exactly like another. I have found that in my 100 gallon mixed reef nothing other than ARM is needed to maintain NSW magnesium levels, but I do water changes, so a part of the total CA/KH/Mag is coming from the fresh saltwater in addition to the Calcium Reactor.
Sometimes a 3 point callibration (4,7,10) can fix issues if the probe isn't reading properly. I'd also take into account how quickly the probe displays the pH of the DT. If it takes too long it could be defective or going bad.
Edit: How is the Co2 diffused into the water in these reactors? Is there a ceramic disc or something or are the bubbles broken up as it passes thru the media? I have no experience with them, but I have been tossing around the idea of Ca reactor vs two-part dosing. I have a 10 lb tank and a regulator but I sold my pH controller and have been considering getting a RK lite. I'm just wondering if my tank is actually big enough to need one. Its only 75 gallons.
Actually, you can't do a 3 point calibration with a pH controller. Controllers only have one or two point calibration. For two point, you may only calibrate a controller between 4-7 or 7-10. Set the controller to function between 4-7, then recalibrate between 7-10 and you just destroyed the 4-7 settings. Calibrate between 7-10, then recalibrate between 4-7 and you just destroyed the 7-10 settings.
Usual practice is to calibrate in the pH range your controller will be in most of the time. For FW planted tank CO2 setups, calibrate with 4-7, for reef tanks use 7-10.
Bad pH probes either cannot be calibrated, will not hold a calibration, or display wildly aberrant pH readings after calibration (not hold the calibration).
CO2 is usually just bubbled into the reactor through the plumbing of the reactor recirculation pump, where it is recirculated through the reactor media. You can use a reactor on a 75 gallon tank. Personally, for me it would depend on if I wanted to play around with a new gadget or not. A calcium reactor is not any better or worse than 2 part dosing, just another way of reaching the same goal.
I do, however, think a calcium reactor might a better option for a large volume reef tank, as once it is dialed in it would require less maintenance than daily dosing. Automated 2 part dosing might negate that perceived advantage, though
