calcium reactor

[dschflier]

My tank currently has a GSA kalk stirrer running. I have had very good luck with this unit and my corals are doing very well.

 

I figure it is now time to ruin this luck by finally turning on the CO2 in my calcium reactor. I have been running the reactor for a couple of months just to see any obvious issues without running any CO2 through it.

 

I do not own any automated PH monitior. I am curious how someone would begin to run a calcium reactor safely just by using standard manual testing. I do have an aquacontroller jr, which I have never set up and think I will look at using that as well, but my initial focus is on seeing if it is possible to set up the reactor with using the minimum amount of supporting equipment.

 

Any suggestions would be appreciated.

[dschflier]

anyone?

[SeanCallan]

Bueller? Bueller?

 

I have no suggestions, I don't trust my manual testing when compared to a computer. Pinpoints are relatively cheap and I'd rather use them then take the risk.

Edited November 10, 2008 by SeanCallan

[Brian Ward]

I haven't actually set up a calcium reactor before, but I read a couple detailed threads on how to do it. Search the forums on calcium reactor setup and tuning. I believe it was Chip (flowerseller) that provided the detailed how-to.

 

From my recollection, I think you're going to want to fire up that AC Jr. and at least use the pH probe to control the pH of the reaction chamber (be sure to calibrate the pH probe). From my understanding, this is primarily what controls the amount of calcium that is dissolved into the water. It's a delicate balancing act between low enough to get the calcium to dissolve but not so low that it drags down the overall pH of the tank. For this reason, many people use 2 pH probes - 1 to measure the pH of the effluent and 1 to meaure the overall pH of the tank. You may find that in order to keep the pH of the tank up, you'll need to increase evaporation (usually by adding fans) so you can dose more kalk.

 

 

 

Good thread on tuning a calcium reactor:

 

http://www.wamas.org/forums/index.php?showtopic=9103

[lanman]

Here's how the thing works - from a 'for dummies' standpoint - because that's as much as I cared to learn.

 

Inside the reactor, you create a 'source' of high-alkalinity water. You do this by running CO2 into the water there, and reducing the pH reading (more acid). The acid 'dissolves' the coral frags inside. You do this by keeping the pH inside the reactor around 6.0-7.0 (look elsewhere for the exact numbers - depends on the media, etc.). So you will need to be able to measure the pH inside the reactor. There is a 'probe hole' on the top for this purpose. THEN - you hook a pump up to the reactor to move water into it from your system; creating a positive pressure inside. This causes your reactor water to want to try and get OUT of the reactor through the conveniently-placed tube that goes back into your system. You then regulate how much of this water is added to the system by a valve, or pinch-clamp or something on that output tube. There are all kinds of fancy calculations - but basically adjust it slowly and measure often. We are talking a couple of milliliters per minute. Try to find the amount that makes you happy - figure it in drops per 10 seconds or something, and you can try to keep it adjusted there.

 

It CAN be done manually - adjusting the bubble count, increasing it if you are moving more water through the reactor, lowering it with less... it's just a long-term balancing act. What you don't want to do is get your pH down to like 5.0 - and melt that coral down into a slag-heap.

 

There... is that the most 'layman's explanation you ever saw, eh? Or perhaps lanman's explanation.

 

bob

[dschflier]

Thanks. As always I can count on WAMAS members for good info. I will have to read over the info a couple of times before I feel comfortable turning on the CO2.

[Origami]

An article for you, Dave. http://reefkeeping.com/issues/2002-05/sh/feature/index.php

 

I've not set mine up yet, but have read this. There are a several things in this article that I've observed. First, the use of a pH probe is highly recommended. The worry is that test kits are too inaccurate for this purpose. Second, people choose to monitor different points in the system when setting up their reactor. One option is to monitor the pH of the effluent, to ensure that it stays low enough to dissolve the media but high enough not to gum it up, reducing the flow. This approach, however, does not prevent you from drastically dropping the pH in your tank. Perhaps this is the reason that some people drip the effluent into their skimmers to "blow off" excess CO2 or into their refugium so the excess CO2 can be taken up by the macroalgae. The second option is to monitor the tank pH to make sure that it does not fall below the level that would melt down your corals. Both options seem to be out there and it would be good to hear from others what they do to monitor the situation.

 

Until I get an aquacontroller, I'm committed to use a recently-purchased Milwaukee pH controller to control my calcium reactor (which should go online within the next month or so). And, if I ever do get an AC3 or AC3 Pro, I just may run it with two pH probes....

 

I invite those who have reactors set up and operating to chime in on how you have your systems set up and why you chose to do it that way. Please! We could use the wisdom of your experience! Much appreciated.

[Rascal]

David:

 

My first CO2 reactor was entirely DIY with no probes or monitors whatsoever. I used a Dwyer valve I found on Ebay to control the CO2. I got it all dialed in without any problems using just Ph and Alk test kits and a couple of bottles of 2-Part. The key was to take it very, very, slowly. This was my method:

 

1) start it up at a fraction of what I thought I would need - I chose 15 bpm and a drip rate of 20 to start.

2) test effluent alk and ph just to make sure it was working (I think I shot for Alk at around 20 dKh and just made sure the Ph wasn't so low that my media (ARM) would turn into mush.

3) test tank ph and alk

4) As expected my tank's Alk dropped the first day. I dosed 2-Part to make up the difference and then increased the bubble count and drip rate very slightly.

5) I continued this process until I got it dialed in. I would test Alk & Ph in the tank every 12 hours just to make sure everything was OK, but not make any more than 1 change every 24 hours. I always made only 1/2 the adjustment I thought I needed to make sure I stayed on the safe side.

 

The whole process took about a week. At the end I went over just a bit (saw a slight rise in Alk), so I made slight decrease to the CO2 rate and then took it offline overnight to allow the Alk to fall. After that it worked fine.

 

One thing I would NOT recommend based on this experience is running a Ca reactor without a solenoid. The problem is that in a power outage I continued to dump CO2 into the sump. When the power came back on all of that low Ph water hit the main tank at once. Not good.

 

I still use a DIY reactor but now I have a high quality regulator w/ solenoid to control the CO2 and I use my ACIII to control the whole thing. My dialing-in process is basically the same though. I test the Alk and the PH of the effluent to make sure it is working, but mostly I keep testing my tank and making adjustments until the Alk is stable at the level I want it. One mistake I have seen people make is to have the flow rate so fast that the water doesn't stay in the reactor long enough to have a drop in Ph, so even when they turn up the CO2, the media doesn't dissolve. This has the effect of just blowing CO2 right through the reactor into your tank without doing anything but dropping the tank Ph. You can tell this by measuring the Alk of the reactor. If it isn't significantly higher than your tank, there is a problem. On the other hand, if the flow rate is too low relative to the bubble count, the Ph in the reactor will drop so low that the media just turns into mush. Once you know at what point your media does this, you can avoid it by measuring the Ph of the effluent and making sure it doesn't drop too far.

[DaveS]

The stuff already posted is pretty good. Just a couple of points to add from my experience:

 

1) the 2 pH probe approach on the controller is super easy. 1 probe measures the pH in the reactor and turns the CO2 on/of to moderate it. The second probe monitors the tank pH. This allows you not only to know the pH of your tank but if the pH in the tank gets too low, the controller can override the CO2 addition to the reactor. Basically the pH in my reactor is around 6.5 much of the day except a few hours after lights off and a lights on. Those are the hours in which my tank pH drops below the threshold and CO2 is no longer added to the reactor. The reactor is essentially off.

 

2) Dripping Kalk is good to bring pH back up. It's not simply because Kalk water has a high pH but there is a chemical reaction that occurs which causes the Kalk to bind with CO2 in the water. Ok maybe the chemical reaction is just what occurs when you mix an acid and base...

[Rascal]

Ok maybe the chemical reaction is just what occurs when you mix an acid and base...

 

You mean like this: http://www.spartechsoftware.com/reeko/expe...nts/volcano.htm

 

Completely unrelated but funny story: I had a client one time who thought it would be cool to pour diet coke (acidic) into a bottle of calcium hypochlorite (basic). He was just a bored teenager working at a neighborhood pool for the summer who meant no harm (and he wasn't seriously hurt), but the Fire Marshall decided to bring felony charges for bomb manufacturing! In court as he justified this charge by explaining to me that an exothermic reaction occurs any time you mix an acid and a base, I wondered what he would do to me if he saw my Kalk mixer at home with the bottle of vinegar sitting next to it. I also wondered if Toys R' Us was about to be charged as a bomb dealer for selling the above-linked "make-your-own-volcano" experiment, and finally I wondered how long it would take for the prosecutor to dump this dog of a case: about 30 seconds as it turned out.

[Origami]

It's not simply because Kalk water has a high pH but there is a chemical reaction that occurs which causes the Kalk to bind with CO2 in the water. Ok maybe the chemical reaction is just what occurs when you mix an acid and base...

 

You're right about the chemical reaction. The CO2 and the hydroxide (OH) part of the kalk powder (which is hydrated Calcium Hydroxide, Ca(OH)2) combine to form a bicarbonate ion (which gives you your alk reading).

 

Ca(OH)2 + 2 CO2 ==> Ca++ + 2 HCO3- (calcium plus two bicarbonates)

 

Normally, this is what happens to kalkwasser when the Ca(OH)2 dissociates in solution and combines with CO2 present in the water column from livestock or from exchange at the air-water interface.

Edited November 11, 2008 by Origami2547

[dschflier]

Thanks everyone for the input. As always WAMAS comes through with tons of info. Tom I will look at the article you hyper linked. I have had an aquacontroler 2 for a couple of years and have never set it up. I suppose this is the time to learn how. Any suggestions on good places to get PH probes and what they cost?

 

Tom the article that you linked has a picture of a calcium reactor in it. That is the exact reactor I have. The one thing I dont see is a place to insert a PH probe in the reactor.

Edited November 12, 2008 by dschflier

[Origami]

Thanks everyone for the input. As always WAMAS comes through with tons of info. Tom I will look at the article you hyper linked. I have had an aquacontroler 2 for a couple of years and have never set it up. I suppose this is the time to learn how. Any suggestions on good places to get PH probes and what they cost?

 

Tom the article that you linked has a picture of a calcium reactor in it. That is the exact reactor I have. The one thing I dont see is a place to insert a PH probe in the reactor.

 

Not sure where to get them. I've seen them on ebay but I think I've read that there may be a compatibilty issue. There are plenty with aquacontrollers here. Somebody should chime in.

 

As for setup, I've read that some run the effluent into a small cup, letteing it overflow into their sump, and place the probe in the cup. Of course, this is what you would do if monitoring effluent pH. If you were monitoring tank pH, you would just place the probe tip in the sump, I suppose.