OK, so I’ll start this by saying that this is mostly a question for Shawn since he has built Ca reactors before, but other people who have experience are welcome to chime in.
I am thinking about building a dual chamber calcium reactor to help maintain calcium and alk. I also plan on getting a RKE to control the tank, and was thinking about incorporating a solenoid valve that is controlled by the RKE, so that if the power shuts off, the valve will close, and CO2 flow will shut off. Otherwise, I was planning on having the solenoid on all the time. I have found plenty of DIY Ca reactor plans on-line, but I would like to hear from someone who has build one them-self (Shawn) about possible ideas on how to setup the system so that it is reliable in its task and fairly low maintenance.
Shawn: I think that you use a probe to monitor the pH of the effluent instead of a bubble counter right. What are the benefits/drawbacks of doing it this way. I am guessing benefits are less fiddling with the flow rate of CO2, but with the drawback of a shorter solenoid life from repeated on/off cycles?
As far as automation goes, I will be getting both the SL1 and SL2 modules for the RKE most likely (the basic package comes with a SL1, and I want a SL2 for the salinity probe), so I will have 2 pH probes. I would like to have one to monitor the tank, but that gives me a free probe that I could work into the Ca reactor. I was thinking I could do it the way that you do, and also have the built in safety that if the tank pH drops to much it could shut off a solenoid and effectively stop the Ca reactor.
Just wondering what your thought were since you have a LOT more experience with these reactors. At the moment its all in the planning stages, so I figured I would ask for advice now before I actually bought anything. That way if you convince me I am going about it @ss backwards, I can change my plans before I waste any $$.
Bellamy - any PH contoller will work. the only thing to keep in mind is the difference between a controller and a monitor. a controller is what you need in this scenario and the RKE will work just fine. as far as the life of the solenoid goes i wouldnt give it too much thought. these things are rated for hundreds of thousands of cycles and will typically last much, much longer. im not familiar with the resolution of the RKE but the simpliest solution is to simply set up a range for the PH will will greatly reduce the amount of wear and tear on the solenoid. i used the large ARM style media from Gen-X(which i liked a lot) and kept my PH range set to 6.8-7.0. I would guess that the solenoid only kicked on two or three times a day max but couldnt tell you for sure. IME experience manually dialing a Ca reactor in with a bubble counter is just plain insane and i cant think of one good reason to do it other than to save money. However, making a bubble counter is still a good idea for troubleshooting purposes. As far as having a backup goes i wouldnt worry to much about it. If you keep your CO2 rate very low i think it would be very hard to crash your tank. Remember that the solenoid is NC so having the controller fail in a way to keep it open would be unusual. Just to be clear, if you decide to not use a controller you do not need a solenoid. A solenoid & controller replaces the needle valve and bubble counter. However, i would still use both a needle valve and a bubble counter for the reasons i mentioned above.
I will share one piece of advice that made my life a LOT easier when constructing reactors. Tap your connectors. I bought Jon Guest style “swivel T’s” that are SO SO nice. Basically, you drill a hole in your reactor and tap it. Then you thread the T into the reactor in a perpinducular fashion. With two of theses T’s you can conect your pump and your effluent. Pump in and water in on one T. Pump out and effluent out on the other T. The best part is that the T’s will swivel freely 360 degrees. I can not tell you how much easier this has made my life!!
I hope its clear but im sure its not. When i get time ill try to take pics and proivde a drawing if i can.
Ca reactors are designed to run 24/7. If you dont run the C02 then the water in will be the same as water out. As you add CO2 the only thing that will change is the water out will be lower in PH. As you add an amount of CO2 that is substantial enough to reduce the PH in the chamber to a point where the media will degrade the effluent will then buffer your tank water and add Ca. Keeping the PH in the proper range will only ensure that the effluent has the capacity to buffer your tank. The actual drip rate of the effluent will determine the amount of Ca that the reactor replenishes. As long as the PH stays in the correct range the output will be consistent. If you reach a point where you have to run the effluent at a rate which is faster than the media can disolve then you simply need a larger reactor.
What I was saying is when your solenoid closes because of a pH drop, it is no longer buffering the tank correct? You said that your solenoid only turns on a couple times a day… so I assumed that it is only buffering at those times (For a solenoid, on is open…right?) What I was asking is if it is better to run it at a lower dosage of CO2 constantly rather than have it put enough CO2 in that it swings the pH and shuts off the solenoid…
Or is it that your effluent slowly creeps down in pH while the reactor is on, and just shuts down temporarily a few times a day so that it doesn’t go to low? Now that I say that it makes more sense…
Just trying to figure out the logistics of how the probe/solenoid works to increase the efficiency of the system.
gotcha. ill try to answer without making things more confusing. sometimes i confuse myself with these posts!
Or is it that your effluent slowly creeps down in pH while the reactor is on, and just shuts down temporarily a few times a day so that it doesn't go to low? Now that I say that it makes more sense...
Not quite. The effluent actually slowly creeps up in PH. In example, assume you set your controller for a PH range of 6.8 - 7.0. When you first start the reactor the effluent PH will be identical to your tank water. The PH probe will read it as such and the controller will open the solenoid valve on the CO2 tank to release CO2 until the solenoid closes. The solenoid will close will then controller tells it to which will be when the PH reaches 6.8. At this range the media will disolve and the effluent will buffer your tank. Your drip rate determines how quickly your effluent will deplete and, consequently, how often you will need CO2. You set your drip rate according to your tanks needs determined by testing. As you drip out the effluent the PH in the reactor will begin to rise. The reason it begins to rise is that the lower PH effluent is replaced by water from your tank at a higher PH. Because CO2 is not being injected when the PH is between 6.8-7.0 it will continue to rise at a rate proportional to your dip rate until it reaches 7.1. Keep in mind that as long as the PH is in the range of 6.8-7.0 CO2 is not being injected in the reactor. As soon as the PH hits 7.1 the controller will open the solenoid and CO2 will be injected until the PH once agains reaches 6.8. Then the entire process continues. The reason why using a needle valve is good is because if you inject CO2 too fast there might be enough CO2 outside of the tank by the time the solenoid closes that your PH could dip far below your low range.
Basically, the reactor’s effluent should always be in the ideal range to disolve the media. It will vary from media to media from what ive read but 6.8-7.0 always worked well for me. To high and nothing happens. To low and everything begins to clog up. The frequency at which CO2 is injected will be directly related to the PH of the effluent which is directly related to your drip rate.
I hope this clarifies if not just highlight any section that is unclear and ill try harder! lol
Ok that REALLY helped. lol. I finally get what you meant by what you said. So is your pH probe in the reactor chamber itself? Or do you have it on the effluent discharge?
In the reactor chamber itself. The have probe holders that have standard male pipe thread that you can screw into your reactor. The probe slides into the fitting and then you tighten the fitting down using a nut to make it water tight. I know i have seen the parts available as DIY but i cant remember where for the life of me.
So does that mean that a second media chamber should be after the effluent PH probe from the primary reactor ? so as it can scavenge any excess CO2 in the effluent and not interfere with the reactor control. its just there as a dumb reactor to react residual corbonic acid and buffer the effluent a bit more before returning it to the sump. If you install a second media chamber.
I guess it would all depend on how the second reactor i configured. Ive seen a second chamber add simply for capacity so that the re-circulation pump affects both chambers. In this scenario the effluent would be identical in both chambers and it wouldnt matter. If the second chamber was plumbed in-line with the 1/4" “drip” tube then yes, the PH probe should be in the first chamber. I know that adding a second chamber in-line is supposed to reduce high alkalinity issues but have never verified this myself.
So do you run just one chamber? From what I have read that works fine, I was simply adding a 2nd chamber for the increased capacity for the space available under the stand. I had thought about adding the 2nd chamber afterwards, but I have heard of plenty of people using just a single chamber that don’t have any problems. Might be interesting to try setting it up one way, seeing how the tank runs, and then setting it up the other to see if there is a noticeable difference.
From what I have read, the 2nd chamber on the effluent line was to make sure that all CO2 was reacted when the effluent hits the tank. If it is a recirculating system, I don’t see as if this should be a real big deal. It might put off a little extra CO2 the first few min of running, but after that it should all be reacted as it recirculates, correct?
It all depends on how you configure the second chamber. If its for capacity plumb it to recirculate. If its to reduce PH and Alk plumb it in line. If you plumb it in line with only your 1/4" effluent line going in and out then it wont have the same PH as the first chamber and would like react in the way that Ken described. Ive never confirmed it though and dont have enough of a working knowledge of the chemistry to explain why it would.
The have probe holders that have standard male pipe thread that you can screw into your reactor. The probe slides into the fitting and then you tighten the fitting down using a nut to make it water tight. I know i have seen the parts available as DIY but i cant remember where for the life of me.
Bellamy - are you even reading my posts? >LOL<
Im only kidding man. Here is what you need. Its the first one i found with a google search but i know ive seen them much cheaper at other places. Im guessing you could probably find one for $5 or less. The nice thing about these is that you hand tighten/loosen the nut to add/remove the probe. Very clean.
Ok, another question, but this one is probably for Glenn or Shawn. What type of threads come on the different types of pipe? I was looking at getting the John Guest fittings, and he has the tap fittings with a bunch of threads available. I was going to thread the holes by screwing in a metal fitting of the same size, but I wanted to make sure everything would line up before I bought the fittings.
P.S. I was going to tap them that way so that I dont have to buy a tap and die set for 3 holes.
[quote=“icy1155, post:16, topic:2724”]
Ok, another question, but this one is probably for Glenn or Shawn. What type of threads come on the different types of pipe? I was looking at getting the John Guest fittings, and he has the tap fittings with a bunch of threads available. I was going to thread the holes by screwing in a metal fitting of the same size, but I wanted to make sure everything would line up before I bought the fittings.
P.S. I was going to tap them that way so that I dont have to buy a tap and die set for 3 holes.[/quote]
iof i am reading your post correctly…you want to use a standard thread size that would be on fittings you would buy at lowes? or home depot right? then the thread style is NIPS>>>national iron pipe size lets say you get a 1/2 inch nips male adapter quest fitting it would screw into a 1/2 pvc female adapter. hope this helps but if still confused pm me or call
Here is a link to a artcle that I used to help build my second reactor chamber. I bought a single size tap bit from tractor supply for @ $5 and used John Guest right angle fittings. One side is threaded and the other end is a quick connect for 1/4" tubing. Hope this is some help to you.
Glenn: Yes, that is the answer that I am looking for. Thanks. That way I can be sure that I am threading the holes with the right size for the fittings I am getting.
For anyone that is interested this is exactly what we will be demonstrating at the meeting! How to properly tap and thread PVC fittings for reactor construction!