Some copied and pasted stuff from over the years. I will try and keep this document green and updated from time to time. If anybody has any suggestions, send me a PM on RC or r2r - jda on both. Feel free to send this link to anybody who might need it.
Preface:
This is for people who want to learn how to use and tune a CaRx. If you want to let a controller do it, then you will probably be disappointed in this content.
Reactors in General:
Most reactors are all pretty similar - they recirculate water, let in tank water, let in co2 and let out effluent. They are simple beasts. Built quality matters. That being said, there are literally a dozen brands that are totally fine - I use Korallin, but I would also use GEO, LifeReef, AquaMaxx, Knopp and many others. I like reverse flow, but with larger media not clogging as much, it is not as big of a deal as it used to be.
You can spend a fortune on regulators and stuff, but if I were starting over, I would just buy a Tunze and call it a day. I have a very expensive dual stage stainless Victor with oil filled gauges and a custom needle valve - the dude that I got it from spent like $750 on it and while it is nice, it does not do any better of a job than the Tunze that I am using, or a m3 regulator. The expensive ones are easier to fine tune, but you can fine tune a cheaper one just as well. You can always add a super-precision needle valve to a "normal" regulator.
A good check valve is super important to keep saltwater out of your nice regulator if power goes out.
I would skip the ph probes and learn how to tune this thing by hand - it is easy, more reliable and will save you trouble down the road. Take the time and learn... it seems like a lot at first, but with just a bit of effort, you will "get it" all of a sudden. Once you learn, if you want to monitor with a pH probe, then cool, but you will be better at this if you know how to do it yourself.
The only media that you can get right now is calcite or dolomite (in 2020) - if you have a LFS that has some Reborn or Natural ARM (old stock), then grab it, but it is hard to come by. The current incarnation of ARM is crushed calcite - get the medium size. The natural media has more trace elements in it than calcite, dolomite or the man-made media, so I like to use it when I can find it - the stuff is melting exactly what the coral uptook when it grew it’s skeleton. Nov 2020 edit: ARM calcite appears to have a good amount of traces in it as well… it is keeping up with magnesium and strontium (had to dust off the test kits). Reborn is available from time to time also, but not consistent.
I feed with a cheap pump like a Quietone 1200 or Maxijet - they seem to last 3-4 years, but they are like $20 to replace so no big deal. I also use a mainline T on one system. You can get an expensive dosing pump (Kaomer, for example), but make sure it is continuous duty. Some reactors will feed themselves, so check this out first. They all work plenty well. DO NOT run a calcium reactor off of a manifold.
If you tune your reactor well, a second chamber will do nothing. If you plan on learning how to tune, then no need in buying one, but if you are sure that you want to use a pH monitor and probes, then get one for sure.
If it were me, I would try and find a used high quality reactor - Geo, Korallin, etc. Buy a new Tunze Regulator. Get a Mainline T to feed. Get a flow control pinch to control the output. Find a 20lb bottle locally - 5 or 10lb are fine, just need refilled more. Get some co2 safe tubing. Order some ARM. Get a Salifert Alk test kit - cheapest and easiest to check effluent. You should be able to do all of this for a few hundred bucks... or you could max out, and go over, that whole stimulus check if you really wanted to.
How to tune:
Set your reactor to 40 drips and 10 bubbles per minute. Wait 24 hours and test the effluent dKh - the goal is around 25 dKh. If you are lower, then add a bubble, if higher, then subtract a bubble. You NEVER want to move both the drips AND bubbles at the same time when tuning. If bubbles are too hard to dial in, then you can move the effluent too… less drips if you need higher dKh and more drips if you need lower. A few bubbles or drips can go a long way. Be sure and wait at least overnight before retesting.
Once you are around 25 dKh, see if it will stay there for a few days. If it does, then measure your effluent rate in MLs as well as drips (eventually, you will not be able to count drops anymore). This number of bubbles and drips is your magic ratio.
Now that you know your magic ratio, then you move BOTH drips and bubbles in this same ratio to meet tank demand - up or down together.
Notice that I did not say anything about pH or a controller or probe. I do not use them and do not recommend that anybody does. They are a waste of my time and provide substandard results over tuning for 24x7 operation.
Hang in there. It might seem hard at first, but usually people get it quickly and it all makes sense. Typically people send me PMs for help and then they stop about mid-way because they start to understand. It will get to the point where you will be able to just look at the effluent rate and bubbles and have a pretty good idea of where you stand.
Few tips:
Somewhere around 25 dKh for effluent output is fine… do not fret over the exact number.
If when you raise or lower in your magic ratio, the dkH moves to 22 or 28, then who cares… if it is keeping up with the tank demand, then leave it alone.
Over time, as your tank demand increases, you will need to increase the output of your CaRx - make a slight increase and test the tank and you should see it slowly rise and then level off. I have to increase mine every few months and it might go something like this… Jan 1 tank dKh of 7.3 which slowly lowers to 6.8 on April 15th and then I turn the CaRx up just a bit which raises the tank dKh up to about 7.2 over the next few weeks, then levels off and then drops again to 6.8 some time in September. The CaRx does not keep the tank completely stable since my demand keeps going up and up as corals/clams/coralline grow, but just small adjustments are all that is necessary to keep up.
Test and pay attention to dKh at the same time every day. Do not worry if your night vs day dKh moves a bit… this is normal.
About pH in the chamber:
It is worthless when dealing with output. The media type, surface area and density will all matter, so the pH needed in one system is different than the media in another. This is the same with bubbles and drips. Take into account that there is no uniform media, bubble or drop sizes and you can see why people just cannot tell you X mls per minute, Y CFM of co2 and Z pounds of media. Your experience with one type of media to the other will require a small tune.
About co2 tanks and gauges:
For low side pressure, you need to turn the knob so that the low side pressure is enough for steady bubble output. Hard to say what a good PSI is since these are not super precision regulators and they can vary by 100%, but raise it by 1 PSI if you cannot get a consistent bubble rate.
Some regulators do not have the ability to adjust the low side PSI - this is fine, one less thing to worry about.
The gauge will show about 800 PSI until the last droplet of liquid co2 is still liquid. The high side gauge will only go down once the tank has nothing but gas in it - this means that you are empty. THIS IS NOT LIKE A GAS GAUGE so remember your simple high school education about expanding gasses in liquid state. You can pick the tank up and see how full or empty it is. Some keep the tank on a mechanical scale and use the scale measurement as a “gas gauge.”
I like to use 20lb tanks, but I have a basement sump and the room is no problem. I have 3 systems using CaRx and I do keep a spare 5lb tank in the garage that is full in case I run out. You can get cheap 5lb tanks from failed home brewers and the like.
Home brewing and/or welding supply shops can fill your tanks with co2.
Salifert Test Kit for High dKh:
(this is from a test kit that I purchased in 2019 - they change all the time, so read the directions)
Follow the directions for the low-res mode - 2mls of tank water and 1 drop of the blue stuff, I think. If you use all 1ml of the final syringe, then get another ML and add the results together.
So if you use 1 syringe and .28 of the next one, then it is 32 for the first syringe (low res) and 9.6 for the part of the second one... for a total of 41.6.
The low res mode goes to 32, so that should cover most CaRx. Also, put the remaining final solution back into the bottle - it goes further this way since I never run out of drops before the larger bottle.
You can use normal resolution mode too, just will nearly always require more than one syringe of the final liquid.
Using pH Probe and Controller:
I do not recommend this until at least you learn how to tune a reactor on your own. You cannot trust the pH probe forever, so you have to know when you need to intervene. I have not used a pH controller for at least a decade and do not have any advice on what to buy or how to use them.
This is the same with the fully automated CaRx setups. The best thing to do with these is to just go 100% into what the manufacturer is saying ang selling.
If you want to use a pH meter to alert you if something is WAY out of whack, then cool, but only have it alert and not stop/change anything. The pH probe is BY FAR the least reliable piece of equipment here, so test by hand before you ever trust what it told you. Some people have them alert if the chamber pH gets above 7.0 which might mean that the tank is empty.
My Favorite Combo:
I should note that I would use nearly any good and well built CaRx and that the differences are very minor. Use setups are a good way to save money. I am only writing this because people ask me quite often.
If I were buying today (new), I would buy a Korallin Reactor, Tunze Regulator, get a 20lb bottle locally, use a MaxiJet 1200 feed pump and find medium sized media (natural if possible).
I like the Korallin because the Ehiem pumps usually last more than a decade and are efficient, reverse flow (can be used with really small media like crushed coral), like that the pump is on top to keep the debris from clogging the effluent line (most debris settles on the bottom) and have a small footprint. I also like that they have survived a few economic downturns and are still in business in case I need parts (2007-2009 was a killer). The Korallin also traps excess co2 at the top and I can tell if my tune needs adjustment.
I have used Geo, Tunze, Korallin, Knop, AquaMaxx, LifeReef, RO and many other reactors and they are all fine. Currently using a Tunze, M2 and Home Made regulator and they all are steady and reliable. I do not use the Aquarium Plants Carbondoser anymore since they seem to only last a few years for me - they are amazing when working. There truly are many, many quality pieces of equipment out there for doing this.
I won an AquaMaxx at a club auction and this unit has a prefilter that traps/captures all small particles and organics and keeps them from entering the reactor. All reactors should add one of these immediately. I love this feature even though I hate other things about this reactor - such is the case with all of them.
Threads to Browse:
I have a korallin calcium reactor that is working great but it cant keep up with my demand. I have the effluent all the way open and ph set at 6.4 inside. Would adding a second chamber help a lot or not really? I really do not want to buy another whole calcium reactor right now. If a second...
www.reef2reef.com
hi everyone. I have a Geo CR618 reactor that has been running for about 4 weeks now. 3 with CO2 added. I have been bumping the reactor down very slowly due to this being my first reactor and I didn’t want to do too much at once. The reactor is still not quite meeting the ALK demand of the tank...
www.reef2reef.com
I've heard a little as 3 hrs and as much as 48 hrs. I haven't played with one before so I figured I'd seek advice. Let me give a simple scenario: (Transitioning over from Triton Core7 BTW) I calculate my effluent dKH and it's 15 dKH. Flow is at 30mL/Min. I test the tank...opps... the levels...
www.reef2reef.com
How do you like that pump, I am looking for a pump for my CaRx and was considering that one.
