Calcium Reactor Tuning/Effluent Readings – 12/15/07
Heya,
<<Howdy>>
I am emailing you guys to see if you can offer me any advice on tuning my Korallin 1502-C Calcium Reactor.
<<Mmm, yes…possibly>>
I have a 90 gallon Reef tank which is filled with many LPS and SPS corals.
<<I see…and with a subsequent high demand for bio-minerals, eh?>>
My understanding is my effluent pH should be around 6.5-6.7,
<<This can depend on the type media and its ready solubility, but generally speaking yes, these are good target numbers>>
but what should my effluent Alkalinity be for my system to be getting an Alk of 10-11 dKH and calcium of 450?
<<I have no way of knowing what is required to maintain these readings for your tank; which by the way, are BOTH approaching the high end of their recommended ranges and thus pose the danger of a precipitous event (please read here: http://www.wetwebmedia.com/calcalkmar.htm). But if the reactor is tuned properly, the Alkalinity of the effluent should be about 20dKH or so. I also want to mention… Don’t expect the reactor to “bring up” already low readings (especially on a heavily stocked system), it’s best to adjust these elements to the desired levels using suitable additives, and then utilize the Calcium reactor to “maintain” the Calcium and Alkaline reserve>>
I am currently running the reactor at 100 dpm and ~18 bpm, but I can't tell if this level is a good level and it just takes time for it to take effect or is my Alk in the reactor to low for my bio-load.
<<You raise a good point…if you are having trouble maintaining Calcium and Alkalinity levels, it may well be your reactor can’t keep up and either a second or larger reactor will need to be employed, or additional dosing/supplementation is needed (Kalkwasser, two-part liquids, etc.)>>
Is my dpm to high?
<<Don’t know…what are the pH/Alkaline readings of your effluent? If the pH is in that 6.5-6.7 range and Alkalinity is around 20dKH then I would say your DPM/BPM are fine (here’s another good article on Calcium reactors and tuning re: http://reefkeeping.com/issues/2002-05/sh/feature/index.php) >>
I am using the Knop Korallith media as I was not getting good results with ARM.
<<Mmm, I have used both and was not overly impressed with either really…for the cost. I’ve gone to searching for/using less expensive “broken coral skeleton” media where I can find it>>
I am also assuming once I find a BPM and DPM that I am satisfied with the pH in the tank will settle a lot more, is this true?
<<A fluctuating effluent pH can affect system pH, yes>>
One final question I have is, is it possible that the Eheim pump I have on my reactor is going somewhat bad, and is one of the causes why I am not getting better results?
<<These are very good quality pumps, but anything is possible>>
I ran it in hot water for some time to try and get a better flow rate.
AJ
<<The “flow rate” is usually pretty low by design (a few hundred gph), but pull the impeller and inspect it for damage/loss of blades. I also suggest you visit the reef chat forums (reefcentral.com/reefs.org) and discuss with those who use your brand of reactor re their experiences/findings/suggestions. Regards, EricR>>

Reactors, Probes, pH - 08/06/05
Thanks Eric!
<<Welcome Aaron>>
I'll prune out everything from the fuge that is not dominant.
<<Tis best my friend>>
I think my ORP is set to compensate for pH, it's around 350 without the compensation.
<<Mmm...the presumption would be the ORP reading is more accurate with the compensation...i.e. - 400>>
I believe the Korallin reactor works well, but I can't seem to get the alkalinity or calcium level lower than this, the effluent pH is 6.5-
<<Fairly common reading for reactor effluent.>>
I thought perhaps I could run the RO effluent through the reactor instead of using Co2, but for the few hours I didn't use the Co2 my alkalinity started to fall, and since top off water only hits the sump a few times a day it might have an adverse effect, but it could lower my alk enough that it's not quite so scary.
<<Maybe you can try reducing the bubble count of the C02...try to increase the effluent pH to about 6.8 or so.>>
I'll try to adjust the reactor again first, perhaps a new needle valve will help, mines getting a bit old.
<<Most of the stock needle-valves are quite "rough", I do believe the are some aftermarket valves that are more precise...at a price of course.>>
I really appreciate your help and I'll add an if/then statement to the halides that turns them off if the pH hits 8.59, trip the alarms and page me.
<<Ahh...a programmer eh?  All good.>>
I've never seen it get higher than 8.51, and if I don't have to worry at that level, I'll start making the other adjustments you
suggested.
<<Yes, not a problem.  In fact, a good level to maintain.>>
On the ORP though, if I turn the pH compensation off, the reading is 350, with it on, it's 400- when you say I should be concerned about this- what do you mean exactly?  Are you saying I should be concerned about the compensated ORP or the uncompensated ORP?  And why?
<<Firstly, if your probe/monitor is designed to be used with pH compensation, use this measurement.  Secondly, I didn't mean to imply an ORP reading of 400 was dangerous...it's when you get much above this (over 450) that problems can arise.  Ozone is a very powerful sanitizer (more so than chlorine), It can be very useful to aquatic systems but must be used responsibly.  For most purposes/systems an ORP reading of 350-375 is adequate...I just want to instill caution when readings start to edge above 400.>>
It doesn’t go any higher, and falls if I change carbon, I do 2x50 gallon water changes a month and it falls a little then, but pops back in a day or two.
<<All normal...and "kudos" on the water changes.>>
Also- this might be a strange one, if I measure RO (effluent) with an electric probe calibrated at 7 and 10, it reads 8.95 (unbuffered RO).  I've three different probes, and calibrated one to 4 and 7- it reads RO at 6.5- <<I believe this to be "more" accurate>> but, and perhaps this is my dilemma, if I add 2 tsp of buffer (Seachem) to about 5 gallons, the dKh hits 10, and the effluent reads 7.6.
<<Yikes!  Might be a problem indeed...I believe if you read the label, one teaspoon treats 40 gallons!>>
Perhaps too much raw unbuffered effluent is getting near the probe and inflating my pH values- am I off-base here or should I try to send the RO through the reactor first?
<<Mmm, try easing up on the buffer first.>>
It's difficult to read a reagent test for anything much above 8.3- purple is pretty much purple.
<<Yes, is why I prefer an electronic pH meter.>>
Why do my probes, if calibrated for sea mix measure RO effluent so high?  If I use a reagent test, it shows at 6.5.  You think RO is getting too close to the probe and inflating my PH reading?  I know it's at least 8.3 with a reg test (the tank).
<<The probe calibrated with the 7 & 10 reagents performs better when reading a pH above 7.0 or so...that's why I said I believe the probe calibrated with the 4 & 7 reagents was a more accurate reading (6.5) of your RO effluent.>>
Is there some way I can prevent erroneous readings using RO in an auto top off system?  I add it through my overflow into the carbon chambers, but the probe is on the other side of that, I thought the drop to the sump would ensure mixing, is it too close?  Can that cause these types of problems?
<<Are you adding raw RO water to your system?  Not the best application, should be buffered (properly) before going in to your system.  As for your "problems", your calc/alk are at their upper limits, but your pH is fine my friend.>>
Thanks,
Aaron
<<Regards, EricR>>

- New Calcium Reactor - Anything Else I Need? -
I just purchased a ca reactor for my tank.  If I use this, will I need to add any other supplements to the tank. <Depends a lot on the type of media you use, but in a general sense... iodine perhaps, but you should always test for this before you add it.> Also, should I try to T the water going into the reactor off the return or siphon it. <Your choice here - both solutions work just fine.> Should I also buy a pH meter or just use testing kits, do you have any preference on the test kits?
<I'm a fan of a digital meter for pH testing, especially with a calcium reactor as you'll have to do multiple tests while you get this thing going. There are many good non-digital pH tests out there, even though I am not color blind, I personally have trouble differentiating between different shades of purple - a digital meter solves this problem and they are very accurate.
Cheers, J -- >

Calcium reactor, pH Controller, Measuring dKH
Hi,
I have had a salt water tank for 25 years, and have been successful with water changes and additives.  My tank is  300 gallons and  just purchased the Knop Calcium Reactor.  Could you give me ANY additional set up advice?
<I'll do my best.> The information included with the unit was a bit sketchy.
I understand the plumbing of the system, but have questions:
1.  The instructions say to measure the reactor output - to be 12-20 degrees DKH.  Is that a simple alkalinity test? <Yes.> Is there a way to convert results from a conventional kit to degrees? <Well, unless the 'conventional kit' contains a specific alkalinity test, no. One the other hand, the units of measure vary from kit to kit, and there is a way to calculate to German degrees of hardness [dKH].> I currently use Aquarium Systems FasTest saltwater aquarium test kit. <Not familiar enough to say if this kit has an alkalinity test.>
2.  I purchased a CO2 Azoo unit and a marine pinpoint ph controller.  Is this necessary to monitor PH swings, for example, at night. <I don't think the monitors are 'necessary' but certainly good to have around.> I read on your website that they are not being recommended.  If this is true, how are the pH swings handled? <Depends on whether or not the pH is actually swinging. A drop in pH overnight might be best dealt with by shutting off the CO2 with the lights.>
3.  During a water changes, the main pump that feeds the reactor will be shut off.  Can I leave the circulating pump on the Knop running? <Yes.>
4.  Once the Knop is set up and running - do I need to continue additives, such as iron, trace elements, iodine, etc..
<Iodine, yes... many others are provided by the dissolving reactor media. Do look at the bucket your reactor media came in - should be a list of what you can expect. Not sure if iron is on that list. Do feel that most trace elements are best supplemented by regular water changes.>
Thank you for your assistance!
<Cheers, J -- >

Calcium reactor questions... effluent properties
Hello <<Greetings, JasonC here at your service.>>
I was wondering what is the best ph to run my calcium reactor with Korallith media. <<Ideally, you would want the effluent pH to be roughly 6.8, not any lower than 6.5... you should also measure the dKH of the effluent and try to tune the reactor to get that to about 15-16.>>
Thanks .
Bill Wann
<<Cheers, J -- >>

- Measuring the pH of Reactor Effluent -
How are all these folks measuring the pH from their reactors? Hold the probe under the drip? We just move the probe back and forth from under the drip then back to the sump input? <I can't speak for everyone, but I'll tell you how I do it... collect a small amount of the effluent in a cup, enough to get the probe on my digital meter working correctly, and then put the pH meter in there... you could also use that collected effluent in a test kit I suppose. Cheers, J -- >