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FAQs on Calcium Reactors, Troubleshooting, Fixing

Related Articles: Calcium Reactors, The Top 10 (Plus) Frequently Asked Questions about Calcium Reactors by Jason Chodakowski
Calcium Reactors and How They Work by James Gasta
Calcium, Understanding Calcium & Alkalinity, Kalkwasser, Calcium Reactors

Related FAQs: Calcium Reactors 1Calcium Reactors 2Calcium Reactors 3Calcium Reactors 4, Calcium Reactors 5, & FAQs on Calcium Reactors: Rationale/Use, Selection, Installation, Operation, Media, Measuring, By Makes/Models, & Calcium and Alkalinity,  & FAQs on: The Science of Calcium & Alkalinity, Importance, Measure, Sources, Use of AdditivesTroubleshooting/Fixing, Products,

All Calcium Reactors require careful monitoring, adjusting... periodic media replenishment...

calcium reactor question; media issue     8/17/11
Hello I've got a 300 g mixed reef system (incl. sump), with growing Sps and a Korallin 1502 reactor. Korallin claims it is good for up to 400g. I can't seem to dial this thing in properly.
My tank Alk meq/l keeps decreasing from 3.2 now to 3.0.
<What are you using for media? I suggest the Knop Korallith product... DO make sure you are buying this... as there are people who package other material and affix the title to it>
Also the only way for my effluent Alk to get over 15 kH is if I increase bpm to make pH get down to 6.3.
<Too low... about the limit here should be 6.8, perhaps at lowest 6.6>
Do I want a broken stream of effluent or maybe just 3 drops/sec.
<A stream should do it>
My bubble rate is 60/min. I have the Digital Aquatics controller keeping the ph between 6.4 and 6.6 with ARM coarse media.
<I like CaribSea as a company (and WWM sponsor), but not this product in most reactors. Again... switch>
Should I decrease the co2 bubble count so that the CO2 stays on longer and never shuts off or will this eventually weaken the alkalinity of the effluent? Or do I not need to worry about the amount of CO2 getting into the reactor and only worry about keeping the ph at a certain level (@6.5).
Should I increase the bpm even more?
<No; I would not... the trouble here is the insolubility, make-up of the media>
But then it will shut on and off every 10 or 15 minutes also weakening alkalinity,.. I also dose Kalk at night with a PM kalkreactor. I've been trying to adjust the reactor now for a month. What is a good bubble rate and drip rate to go with in others' experience? Thanks.
<Cheers, Bob Fenner>
Calcium reactor question... probe and media issues  8/19/11

Hello, I have a 300 g mixed reef system with a few growing Sps running for a year now. I've got a Korallin 1502 calcium reactor with coarse ARM media.
<Not the best/better choice... Read here: http://wetwebmedia.com/KorallinReacF.htm
I am running about 60 BPM and broken stream of effluent. The KH of the tank continues to slowly drop. I can't dial it in. But my main question is I have the Korallin retro lid with the ph probe port, where I have a pinpoint probe in it. I also have a DA ph probe in my effluent cup 3 feet away. Both have been properly calibrated a dozen times in 2 months. The odd thing is that the probe in the reactor itself never reads below 6.9 and only varies between 6.89 and 6.92, however the probe in the effluent changes properly when more CO2 is added going all the way down to 6.3 and will vary between 6.5 and 6.7.
<See and read the linked files above the citation above>
When I take both probes out and test them in the ph 4 , 7, and 10 packets they both read perfectly. What could be causing this problem?
<Probe issues, calibration, current around the tip...>
Is too much tank water entering the reactor itself at once and possible skewing the ph there?
<Mmm, can't tell... The pH needs to be measured near (the one not three feet away) from the effluent/discharge>
What's the use of having the ph probe reactor top if it doesn't work.
I've been using the effluent probe to calculate CO2 because I believe its reading. Could it be that the pinpoint probes don't work properly when installed in the DA RKE system or vice versa?
<Mmm, no; should work wherever employed>
<Change the media, check the contact resident probe membrane, move the distal probe. Bob Fenner>

reef question, H2S from... Ca reactor?!   2/27/11
I have a problem with my 180 gallon reef tank with a 50 gallon sump. I do not have a LFS and couldn't find anything online. THANKS IN ADVANCE for any effort on this question.
my calcium reactor has always had a bit of "rotten egg smell"
<?! Wonder what the source of sulfur is>
when I open the drip line up to a stream to purge air bubbles. long story short I shut off the drip to the tank for a week or so because the calcium and alkalinity where on the high end of acceptable range.
<I'd just turn down, slow the flow of the CO2>
now the clear flex line feeding the calcium reactor has turned black and the effluent from the reactor smells stronger of hydrogen sulfide.
my question: do I have to try to remove the blackened supply tubing and everything else related. the reactor is clear and seems fine the recirculating pump was on the week it was not dripping in the tank.
<You do not...>
OR If I run 20 or so gallons of water through the reactor and discard it while doing a water change will I be ok to put the reactor back in service?
<Likely so; yes>
any ideas or input would be greatly appreciated. THANKS AGAIN.
<Summat is wrong... with the media? The carbon dioxide gas? Likely with an over-fed food source. Bob Fenner> 
Re: reef question, Ca reactor H2S anomaly  2/28/2011

THANKS SO MUCH for your quick reply on a Sunday. I was considering dismantling/removing the calcium reactor. few more questions.
I think it got stagnant and the hydrogen sulfide built up because of the very slow drip rate.
<... do you have Sulphur in this reactor? Other than Methionine from foods...>
I have a mostly unstocked 180 gallon reef aquarium. rbta, 9 fish, couple mushrooms, star polyps. I do have 225 pounds or more of live rock.
my new question. how do I keep it from happening again.
<... grammar>
I obviously need to increase the flow through of the calcium reactor. but I have two concerns. too high calcium/alkalinity and it will lower my ph in the aquarium which I struggle with already (in the 7.9 to 8.1 range daily).
and the linked files above>
is my tank too light at this point for the reactor? can I run it at a higher ph and faster flow rate? ideas?
<... Please read here: http://wetwebmedia.com/calcreacop.htm
thanks again! Andrew
<Welcome. BobF>
Re: reef question, Ca reactor H2S anomaly  2/28/2011

THANKS SO MUCH for your quick reply on a Sunday. I was considering dismantling/removing the calcium reactor. few more questions.
I think it got stagnant and the hydrogen sulfide built up because of the very slow drip rate.
<... do you have Sulphur in this reactor? Other than Methionine from foods...>
I have a mostly unstocked 180 gallon reef aquarium. rbta, 9 fish, couple mushrooms, star polyps. I do have 225 pounds or more of live rock.
my new question. how do I keep it from happening again.
<... grammar>
I obviously need to increase the flow through of the calcium reactor. but I have two concerns. too high calcium/alkalinity and it will lower my ph in the aquarium which I struggle with already (in the 7.9 to 8.1 range daily).
and the linked files above>
is my tank too light at this point for the reactor? can I run it at a higher ph and faster flow rate? ideas?
<... Please read here: http://wetwebmedia.com/calcreacop.htm
thanks again! Andrew
<Welcome. BobF>

Sand clumping and Calcium reactor tuning   12/7/10
My new 185g tank has been running for about 4 months. The sand bed is about 1" of CaribSea Aragonite "Sea Floor Special Grade". I have a Reef Octopus dual chamber calcium reactor with coarse A.R.M. media.
<I like/use a good deal of CaribSea's products, but am not a fan of their Ca. reactor media. Read here:
The CO2 is controlled with an Apex controller to a pH set point of 6.5 in the first reaction chamber. I am running a Reef Octopus protein skimmer and using activated charcoal in a PhosBan reactor.
<Not a fan of this either. Unnecessary, expensive and of deleterious action in many cases>
The following parameters, measured with Salifert Kits, have been stable for several months with this setup:
Temp 77F
Salinity 1.025
pH in calcium reactor 6.5
pH in tank varies between 8.05 and 8.2 (low at night, as expected)
Alk 14.7dKH
Ca 400
Mg 1200
NH4, NO2, NO3, PO4 all near zero (about as low as I can measure).
Prior to adding the CR, I wasn't able to get the pH above 7.8.
As you can see, I have the opposite problem from many other posts: Ca/Mg is good but Alk is very high. I do not supplement with Kalkwasser or other. I do not have any white precipitate or cloudiness except if I stir up the sand bed.
<I suspect the sandbed is the source of most of your alkalinity and the "free" CO2 the catalyst melting it out. You might want to experiment not feeding so much carbon dioxide... set the discharge pH at 6.8 or so...>
My only sand-sifting critters are 4 Nassarius snails, but I have about 20 Turbo and other snails to control nuisance algae and a star for detritus removal. The tank also has around 8 small corals at this point (Montipora and Porites) and one six-line wrasse, all living in about 150 lbs. of live rock. The corals seem to be growing well, but we are not yet seeing much coraline algae;
<Umm, all need some HPO4...>
there has been a fair amount of nuisance algae during the establishment phase. I regularly clean the glass and groom the sand. I do a water change weekly of around 5% and have an automated top-off system to
add water as needed. I use RO/DI water and mix it with Salinity brand salt for the water changes.
Last week I left the tank running under automation for 7 days while I was out of town. When I got back, I found that large sections of the sand bed had turned into a hard conglomerate 1/2" thick requiring removal and smashing with a hammer!
<Mmm, yes, the alkalinity precipitating out... cementing all together>
Mostly, this occurred near the front of the tank where I get the most down-flow from the Tunze Streams. I can think of only two differences during that week: (1) I was not there to tinker with the sand, and (2) data logs show that the pH increased to between 8.15 and 8.3 (no houseful of mammals breathing out CO2)
Question: What might have caused this "bricking" of the sandbed?
Did the high Alk cause this problem?
<Ah yes>
Did the slight increase in pH play a role, and if so, how do I control it when I'm out of town?
<The pH rise is a result of the shorter terms melting of the carbonate, bicarbonate parts of your substrate... this material is "more easily" soluble than the ARM product.>
If the bricking is caused by the high Alk, I'd guess that I need to "turn down" the CR but I am not sure how to do this given the results of the following experiment:
<Just less CO2... set your controller to a higher pH as stated>
In order to figure out how I might adjust the CR, I tried several effluent flowrates, that being my only apparent degree of freedom. After letting the CR stabilize for a couple of hours, I measured the flowrate (time to fill a 30ml vial), the effluent pH, and the effluent Alk. I then computed the net addition of Alk by the CR per minute.
As an example, the nominal tank value is 5.25 meq/L and the effluent at 65 ml/min is 8.78 meq/L with pH near 7.0. Thus the CR is adding alkalinity at a rate of ( 8.78 - 5.25 ) * 65 / 1000 = 0.23 meq/min. I repeated the experiment at 300 ml/min and got effluent Alk of 6.0 meq/L. This makes sense; at a faster flowrate, the effluent has less time to pickup minerals ... however, the net rate of addition still works out to be about the same; the lower concentration is just balanced by the greater volume generated.
<Yes, but importantly as a difference, less carbonic acid is dumped into the main-display>
This leaves me with no apparent way of altering the rate of addition of Alk to the tank. The output flowrate does not seem to be useful as I had expected and the CO2 rate is already automated to hold the CR output pH at the ideal A.R.M. dissolving pH of 6.5. I could adjust the reaction chamber pH, but I'm not sure what would be the best set point to maintain.
<Again, need to experiment... perhaps in tenths of a pH point>
Question: Am I doing something wrong in my experiment? How should I adjust the calcium reactor? Is there something else I'm missing?
<The effluent pH is what I would aim to manipulate as the single variable for now. IF you have occasion to change out the substrate to something less soluble... or even add a good deal on top of what you have... this may cut the high alkalinity. Doing nothing else at this point will only lead to the dissolving (in not much time) of your present one inch deep sand bed>
Thank you very much for any insight you can offer.
<Does this make sense to you Edward? Cheers, Bob Fenner>
Re: Sand clumping and Calcium reactor tuning  12/7/10

Thank you for your reply. Let me summarize what I heard to see if I understood:
<Please do>
* My alkalinity problem may be due more to the dissolving of the sandbed than of the CR media. My main course of action would be to raise the pH of the CR output to reduce dissolving in the sandbed.
I can measure the output pH, but what I am trying to shoot for?
The sandbed clumping is hard to quantify. Is there a target output alkalinity (concentration or flowrate) that is optimal? Shall I just aim to dial down the concentration by say 50% ?
<I'd lower the CO2/bubble count... raise the pH by tenths of a pH point... 6.6, 6.7, likely 6.8 will do it, and measure your system water for Alk., Ca and Mg concentration. I'd not be so concerned re keeping Ca higher than 350 ppm as long as Mg and Alk. are in line>
* I should also consider a substrate change to something less soluble.
Can you recommend an alternative substrate.
<Mmm, yes: http://wetwebmedia.com/marsubstsel.htm
and the linked files above>
I am not running a DSB, so it is for decorative purposes.
<Mmm, no; not really>
However to hide the rock-work supports, it needs to be 1" or more deep, so I don't want something too fine.
* I should target CR output pH around 6.8.
<A good place/guess>
I need to try a pH probe on the output since my reported level was based on a color-indicator test kit made for high-range pH. Recall that I am currently controlling the pH in the first (recirculating) reaction chamber which is at a lower pH than the eventual output effluent. Can I keep the control point where it is?
<I would raise it>
* Regarding the CR media thread you cited, I assume you suggesting trying coarse-grade Korallith media or did I miss the point?
<You are not missing>
* Filtering with GAC may not be desirable.
<Likely as not>
Though a tangent, perhaps you could comment further <Not at this time. My thoughts, opinions, interpretations of fact, methods and attitude are archived on WWM>
<Warm regards, BobF>
Re: Sand clumping and Calcium reactor tuning  12/7/10
Thank you for all your information. I have some things to try now!
<Do please report back your efforts/findings. BobF>
Re: Sand clumping and Calcium reactor tuning 1/9/11

<Hey Ed>
OK, here are some results ... basically, the key suggestion of raising the pH set point in the CR did the trick. I settled on the following settings:
Reef Octopus Dual Chamber Reactor
Reactor effluent flow rate = 130ml/min (timed by stopwatch)
pH set point inside the reactor = 6.8 ( varies +/- 0.02 )
pH of the return effluent = 7.2
daily variation of pH in main tank 7.97 to 8.1
Alkalinity 11.5 to 12.5 (much better than 14.0 - 15.0 I had before)
Ca approx 380ppm, Mg approx 1200ppm
This is a much improved situation, Thanks Bob.
<Thank you for this update! BobF>

Low Alkalinity even with a CR, Calcium Reactor  11/12/10
I really am puzzled. I've read your articles on Calcium and Alkalinity and found that a CR is considered a great way to maintain proper levels of CA and KH.
<Can be... though there are "variations" on how to "do this", and anomalies... mostly re core/media and quality of CO2 et al. reductant applied>
I have a CR in my 125g tank but I don't have many SPS corals. As a result, I saw my CA rising to pretty high levels (500+) so I dialed the drip rate back considerably.
<Might I ask you to measure, report the effluent pH of your reactant discharge water?>
I concluded that I was putting more CA in my tank than was being consumed. As a result of the reduced drip rate, I now have a KH of 6. My CA is at about 460.
<These are fine measures, levels>
To raise my KH a bit, I've begun an old routine of dosing KH
<I take it you mean/t Kalkwasser. This practice, addendum is fine as well>
using a pump that comes on for 1 minute at a time 3 times during the night, i.e. 2 a.m., 4 a.m., and 6 a.m. The drip rate is very slow to avoid a spike and hopefully raise the KH to about 7 or 8 over time.
My real question is why does my CR not maintain the CA and KH as expected at proper levels?
<Mmm, see the above statement. What/which media are you using? Do you have "high" quality "acid"... CO2 likely employed? What re your Magnesium concentration?>
Is the answer as simple as I really don't need a CR?
<Perhaps... what is your desire for using such?>
I would appreciate your thoughts on this.
<Let's keep chatting this up Gene; till you're satisfied w/ your understanding. Bob Fenner>
Re: Low Alkalinity even with a CR 11/12/10
Hello Bob -- nice to hear from you! Hope you are doing well. Enjoyed seeing you in Orlando.
<Ahh, a very nice time>
The effluent readings from my CR are as follows: CA=460; KH=8 -- haven't tested the pH but will do so ASAP and report.
<These are fine values... as long as the pH is not below 6.0 I would not change much here>
The media is CaribSea A.R.M.
<Ah yes... a "natural" (with too much shell/calcite IMO) product. There are others. Do try another brand next purchase>
My CR is a dual chamber design -- and I use a PinPoint controller -- I can provide HI and LO settings if you want them.
The dosing I'm doing to raise KH is Soda Ash I get from Bulk Reef Supply --
<A worthy company in my estimation>
I tested the change in pH today when the pump is on for 1 minute. It changed the pH by .05, i.e. from 8.10 to 8.15. This is occurring 3 times during the night.
<Is fine... again, I would not change this, these settings>
I use 2 different test kits: API and Salifert -- the readings are fairly similar, with Salifert more precise.
<Ah yes>
Really appreciate your help. I invested some serious money in this CR -- hoping that it would make life easier -- and for most I think it does.
<It does, and will do more if/when you are more "into" biomineralizing life>
Just can figure out why my CA rises to such high levels using it.
<Simply put there is more soluble calcium in the A.R.M. CaribSea product than ready carbonate, bicarbonate... Again, you can/could make this up in a few ways... as you are currently doing, simply adding some "baking soda"...>
That's why I backed off on the effluent drip rate -- CA was going off the chart. Now, of course, CA is more reasonable with KH in decline. With your help -- we might get this puppy dialed in properly.
<And you, BobF>
Re: Low Alkalinity even with a CR  11/12/10

Here ya go, sir.
All numbers from the effluent:
pH = 7.6
<Whoa! I'd turn up the CO2>
CA=450 (Salifert)
KH=10.4 (Salifert)
CA=460-480 (API)
KH=9 (API)
pH of the sump water, i.e. display tank too -- 8.0 to 8.1 (calibrated today)
What media do you recommend for my CR?
<... Please read here: http://wetwebmedia.com/calcreacmedia.htm
You can skip our corr.! B>
Re: Low Alkalinity even with a CR  11/12/10
Hey Bob -- would increasing the CO2 really do any good when using a controller?
<Mmm, yes; if the means/extremes of the setting will allow further infusion...>
i.e. wouldn't it simply speed up the process of lowering the pH of the effluent but not really change the pH of the effluent?
<If the lower setting is not reached as yet, yes>
I guess you can tell -- I have limited experience and understanding of this whole process!
<I'd try experimenting here a bit... changing the bubble rate, pH setting/s on your controller. BobF>
Re: Low Alkalinity even with a CR  11/13/10
I made the change yesterday afternoon. Will check the effluent later today and report
<Real good. B>
Re: Low Alkalinity even with a CR  11/14/10

Here ya go Bob:
From the effluent
pH = 7.5 (not much change yet)
<Something errant here... adding more CO2, increasing the bubble count, is not driving down the pH>
CA = 500 (Salifert) 460 (API)
KH = 8.0 (Salifert) 8.0 (API)
From the tank
pH = 8.0
CA = 470 (Salifert) 440 (API)
KH = 6.2 (Salifert) 8.0 (API)
<These values are fine>
While the Salifert kit may be known for greater precision -- frankly for a color blind boy -- it's more difficult to use than the API kit. The color change is to subtle for me -- so I tend to use the API kit more often -- the change in color is more dramatic.
BTW, the HI set point on my controller is 6.67. With the new faster bubble rate, after the CO2 stops the pH in the CR drifts down to 6.39 before starting up.
<... yet the effluent pH is 7.5?>
Isn't it interesting that my tank pH is so low with the effluent pH being higher than what many get from their CR? My thinking at this point is that my low KH is contributing to my low pH. That was why I started the drip of Soda Ash a few days ago.
<Mmm, not too unusual, and again, I would not likely adjust the pH... would leave at 8.0... fine for fishes>
Also, I would expect a higher level of KH coming from my CR than 8.0 -- although the CA is high enough to suit me.
Maybe I should shut the system down and change out the media.
<Ah yes. A good idea>
Hanging with you on this one,
<Glad to be, BobF>
Re: Low Alkalinity even with a CR 11/14/10

Bob, you mentioned that 8.0 was fine for fish -- true -- but I also have corals (mostly LPS, leathers, and a few SPS). Wouldn't that require a pH of
8.2 or 8.3 for satisfactory growth -- and possibly long term survival?
<Would be better... but not likely to easily achieve w/ such high Calcium...>
Frankly, at this time -- everything in the tank looks great. But I know looks can be deceiving. :)
<Indeed. B>

Korallin denitrator 5/16/10
Hello, I purchased filter 5 weeks ago. It reduced my nitrates to zero within weeks. Fourth week water became super cloudy in filter top and then my tank became cloudy. I was using a real slow drip rate. 1 per second.
I increased it and still cloudy. I took out coral media because it was suggested it was being melted and causing cloudiness. Tank cleared up for two days. Then cloudy but not as bad. Meantime nitrates and nitrates remained at zero. Ph though was behind dropped coming out of filter 7.4 or lower. I purchased ph buffer but it was still falling after two days.
Cloudy water and dropping ph are my problem. Filter works great on nitrates but killing ph. I had inlet in sump for biodenitrator, which worked. They recommended it to come from tank. Which I can do if this
would help?
<I doubt this would make a noticeable difference.>
Marine depot thinks there is co2 bulling up in filter and melting coral and dropping ph.
<Could be the case, but a slow effluent at 7.4 should not bring the whole tank down as bad as it sounds. What size tank is this on? What is the tank pH?>
I can't find any reviews stating having my problem which is even more frustrating. I turned off today. I don't want to abandoned it. I saved up for it forever!
<IF this is indeed causing your issue, there are solutions. One of the simplest is to rid the water of excess CO2 before it returns to the tank.
A little powerhead directed through the effluent stream towards the water surface can work wonders here. Some will even have airstones under the effluent line to accomplish this, but then you have bubbles that can return to the tank to deal with.>
<Welcome, Scott V.>
Re: Korallin denitrator 5/16/2010

75 gallon tank. with a wet dry 125 filter. pm 100 protein skimmer.
<Some will even run the effluent back prior to the skimmer intake to blow off the CO2. This does work, but does void the warranty with some skimmers.>
Nextreef nitrate reactor with nitrate sponge media...didn't help so bought Korallin.
<Have you called Dave at Nextreef re this? This is a first class company and people. I would give them a ring. The reactors have some differences, but the base function is the same.>
tank ph is 7.8 to 8 from test kit.
<An okay range.>
bought Kent liquid ph buffer to help raise it.
<This will not work long-term if CO2 is the issue, being constantly introduced.>
tank inhabitants are a small snowflake eel. pixie fire hawk and a damsel.
tank going for 2 years. sorry for bad punctuation. typing from cell phone.
<See: http://www.wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm,
point F.>
thanks for your advice
<Welcome, Scott V.>

CR set up 5/15/10
Hello Crew,
My dual-chamber calcium reactor was set up on Tuesday, 5/11. Today, Friday 5/13 (morning, lights have only been on 2 hours) my readings are as follows:
Tank Water
pH = 8.4 (per API test kit) (2 yr old probe reads 7.99)
KH = 12
CA = 420
Effulent from CR
pH = 7.4 (per API test kit)
KH = 33
CA = 620
The drip rate of the effluent is just a little faster than 1/second. I'm using an American Marine controller which has set points of 6.4 (LO) and 6.62 (HI) - thus, the CO2 kicks in when the pH in the reactor reaches 6.5.
Question: Do these readings seem reasonable and should I make any adjustments at this time?
<You're likely fine here... I'd measure for Magnesium, read re on WWM... adjust if necessary, too far out of ration w/ [Ca]. Bob Fenner>

I need your expertise for a sec. Mr. Fenner. Knop Ca reactor troubleshooting  -- 12/15/09
Hi Bob I'm Jeremy I'm in the Vegas reefers club and you came and spoke for us a while back.
<Ah yes. How have you been?>
Anyway I couldn't really figure out how to post on the forum so here goes.
<Oh, there are links... Here: http://www.wetwebmedia.com/WWMAdminSubWebIndex/question_page.htm>
I have an SPS dominant 180 with an om 4 way and some Tunzes, I top off full strength Kalk and run the Knop s type reactor. The Knop has been giving me issues since I got it a year and a half ago.
<Mmm, what sort of "issues?"... Do you use their/Korallith media? Have you read here?
and the linked files above?>
I have a med/heavy stocked tank and have a larger cal/Alk draw now and need some output from the Knop. I run maybe 1 bubble per sec through the reactors bubble counter (smaller bubbles than a normal bubble counter I think) and about two drops per sec maybe 2 1/2. If I let it run for a few days ill get a large co2 bubble
<Likely not this gas but...>
at the very top of the reactor which I think is part of the problem (co2 not circulating).
<Mmm... or more likely a less than needed-purity of carbon dioxide and/or media. Do please see the link above>
I get my effluent to about 15-18 dKH and I don't use a solenoid I just adjust it to the right ratio and let it go and assume at 15-18dhk I'm at about 6.65 or so (safe) ph in the reaction chamber. I use Korallith medium grain size by the way and have always.
<Oh! Good>
At 15 dKH effluent I'm sure I need a pretty rapid drip rate to keep up with my consumption. I would like to stop topping off with Kalk
<Both the reactor and drip can run on the same system; no worries. Even Daniel Knop does this>
but until I get the reactor working correctly I'm relying on Kalk and extra evaporation using fans and my Alk has been sitting at 7.5 - 8.0 and calcium at about 370
<These numbers are fine... Do you measure, attempt to adjust ORP?>
and I've always ran lower numbers but mostly stable, I just want to get this Knop working before I sell it and get a geo or Korallin. Thanks so much this has been driving me nuts for too long and I know you are the one to talk to about the Knop s.
Jeremy Zedan
<Do look over the link, try a different source, better grade of CO2. I think this will solve your gas bubble issue. Bob Fenner>

Korallin Calcium Reactor Co2 leak -- 10/9/09
Hello Bob,
I have a Korallin Calcium Reactor that has developed a very slow CO2 leak
somewhere between the CO2 cylinder and the "bubble counter". Can you detail the steps I should take to find the leak?
<Yes. I'd take the unit outside (where there is much more air)... and carefully spray water from a clean pump bottle (and see below)... to detect the exact area of leaking. Again I would NOT allow the unit to continue to operate in your home or office>
Typically a 5# cylinder will last almost a year, because of this leak, I only get a couple of months now. My regulator gauges show a full cylinder pressure of 55-60 psi,
<Mmm... need to measure by weight... nor pressure>
the reactor side of regulator starts out at 30 psi, but then will drift down to 20-25 psi after a couple days or so.
<Carbon dioxide is toxic to breathe... binds hemoglobin... I would definitely make sure you have a working CO/CO2 monitor in the area at all times>
I run the system with 6-7 bubbles per minute. I also use a brass check valve in between my regulator and bubble counter.
<... with no plastic/vinyl tubing on the high pressure side>
However, I am suspect of it holding 100%, because it seems there is a little water in the low loop of the line when the cylinder de-pressures. I am on my third CO2 cylinder, so I do not feel it is the cylinder valve (each cylinder was different from the previous).
<"It" should definitely not be>
I have also used Mr. Bubbles around the connections, but found no obvious leaks. My regulator is around 8 years old. Do they have to be rebuilt at some point?
<Mmm, replaced more than rebuilt. I would take this whole rig into the "gas shop"... they have electronic diagnostic tools for detecting CO2...>
If so, who does this? The whole calcium reactor system came from Korallin, and as I said, is around 8 years old. Can the CO2 tubing itself leak?
<Yes... can crack... gets brittle with time>
Are we suppose to change that out at certain intervals?
<I would... Every two years>
Not being able to find this leak is very frustrating. Any suggestions will be greatly appreciated!
<Randy, please do turn this unit off... Get it tested... keep your windows open! Bob Fenner>

Ca reactor 4/22/09
Hi Scott,
I've been having problems lately keeping my alkaline up. Im scratching my head because calcium reactors are supposed to maintain BOTH calcium and alkaline in equal proportions.
<Ideally yes.>
Lately I've kept the calcium reactor running 24/7 and noticed my calcium slowly rise to about 500ppm over the last few weeks and my alkaline tends to drop faster than the calcium. Why is there an imbalance of consumption, more carbonates being consumed than calcium?
<Possible, more likely an imbalance in production. Over what period of time did the imbalance occur? Were the ratios balanced to begin with?>
I've turned off my C02 the last week or so and been adding only KH buffer to get my calcium back down, now levels are ideal at about 440ppm cal. Alk. 8.4
If I plug back in the C02 in my calcium reactor again, I have a feeling my calcium will go back up to 500 and I will run into the problem of keeping up my alkalinity constant around 9dkh. Should I invest in a Kalkwasser reactor?
<I would not...the Ca reactor should do the trick.>
I've read a few instances and seen a couple of picture setups utilizing both reactors for sps setups.
<For a few reasons, phosphate precipitation, ph stabilization...but both are not needed for Ca supplementation.>
Lately I've been adding a full tablespoon of KH buffer everyday just to maintain carbonate concentration. I'd rather find a more convenient way of maintaining this if it's a tweak with cal. reactor settings or investing in a Kalk reactor.
<Do you buffer your top off water? This could be an easy solution.>
It may be possible I had too much C02 being added to the reactor..dissolving too much media too fast...therefore adding too much calcium to the tank.
<It should raise the KH also.>
Your thoughts appreciated,
<A few questions for you: how old is the media, what brand? What is the KH and ph of the effluent? Some of these media out there become mushy and channel the water when run at too low a ph.>

Help! PH in tank fell to 6.5 overnight!!   9/16/08 Yikes!! Last night I did some adjusting on my Calcium reactor. <... too much acid> For a while now I've been seeing my Alk way too high at 13+ so I decided to turn it off, let the Alk come down slowly, then turn it back on once things normalized which I did. I tested my levels again and found Alk at 10.5-11, CA at 420, and Mg at 1250. I turned it back on last night and adjusted for a slightly lower than normal rate of CO2 (about 15 BPM). When I came in this morning I found my CO2 blasting away through the bubble counter and my tank PH at 6.5!!! I immediately panicked and turned the CO2 all the way off. I then opened up the lid to my tank, opened all the windows, turned the fan on my sump on, and then mixed up some fresh RO water and some baking soda in an attempt to get it back up. <Needs to be done more slowly...> I mixed the mix up to about 8.3 PH and added about a half of a regular sized pitcher to the sump. I have a 150 gal tank with a 30-40g sump. After about a 3 hours I looked at my PH monitor again and it is now showing 7.78. Did I raise this too fast? <You'll see> What would have been a better way of doing this? <Mmm, the same, but slower> Thanks for all your help!! -JP <Bob Fenner>

Knop "C" Reactor part   8/20/08 Hi guys, I recently bought a used Knop "C" reactor which came with no instructions and to my surprise not all the parts. <... I take it you bought this "second hand"> I've been reading your FAQ's and found out that I'm missing the valve that controls the effluent leaving the reactor. I've read that I should contact Diana, <Di was the N. American distributor years back...> but I can't seem to find the website. When I do a search for knopproducts.com it comes up with some weird site with different topics listed such as breast implants. <Heeee! A typical "Net ruse"> This is not the site I'm searching for. Any help here would be appreciated. I also noted in my lengthy reading that I may drip the effluent into my skimmer to eliminate excess Co2, if I were to have a problem with precipitation. I have a BakPak skimmer, which side would I use? Thanks for the help in advance. Craig <I've BCC'd Diana here to see if she has the part you're looking for... otherwise Marine Depot (.com) is the current monopoly source. Bob Fenner>

PH issues, SW, reading...    7/24/08 Hello, <Howsit?> I always turn to your website for expert advice and guidance. I have a 90G Reef tank. Added a new KNOP Calcium Reactor few weeks ago. Since then the PH has been slowly dropping. <Mmm... a setting, set-up/operation or media choice issue, perhaps both> PH range 7.88 - 8.04. Alkalinity - 9.2 Calcium - 400 What is the best way to raise PH without affecting Alkalinity? <... posted... and I wouldn't actually "do" this... id est, your pH is fine as stated, measured> Would Baking Soda be a better choice?. <No... if anything, you could do some Kalk addition...> Thanks in advance. Regards, Suresh <... read: http://wetwebmedia.com/marine/index.htm Maintenance > pH, Alkalinity > Bob Fenner>

Carbonate Super Saturation (Bio-Mineral Imbalance) -- 04/02/08 Hey guys, <<Tom>> I have a dilemma and just wondered what the best methodology was here. <<Okay'¦let's see>> I have a 900 gallon system, <<Neat>> I definitely have carbonate super saturation (though haven't seen any snow). <<'¦?>> I am running a large reactor now with 50 lbs of Gen-X media, it's a diy yourself but Alk coming out is 29 dKH and pH is 6.5. <<Okay>> This is all the result of low magnesium and a kalk accidental overdose, <<Ah, I see>> but long story short I am looking for a permanent fix here. <Mmm'¦>> If Alk is 8, ca is 320, if I add buffer Alk drops to 6, ca is literally dropping on its own right now by 80 ppm in under 24 hrs with the reactor running. <<A serious 'out of balance' condition exists'¦ And even though you don't 'see snow,' I think you are experiencing a precipitous event at a microscopic level>> I thought I had it pinged yesterday with Alk of 8 dKH and ca of 400, pH dropped from 8.15 to 8.07 during the day. MG is 1500 (that's because I have been running the reactor 24x7 to keep ca and Alk up). There are 2 300 gal tanks a sump and a 160gal display. <<Wow'¦one of the few with support volumes greater than the display'¦excellent>> The display has 1/2" of sand in it; some of it has solidified due to the super saturation. <<No doubt>> This is what I am thinking, vacuum out the sand, cut out and drain one 300 gal tank making the system size smaller, <<I don't understand this'¦>> NO MORE BUFFERS, <<Agreed>> and good water changes until the reactor handles the load itself. <<This sounds smart to me>> From there I would bring the 300 back online with additional new water added to the system over a period of days. <<Ahh'¦okay>> The other way is to cut out the display as well but if I do so I fear it may be too much change too fast. <<Possibly'¦and the water changes should help quickly>> Finally, the only other place carbonate could have settled is in my trash can DSB (Calfo's bucket), but I really don't want to cut it out as it is well established and I don't want to have to deal with SPS and nitrates! <<No need to remove it'¦but do check to make sure water can still get in to/through it>> Let me know what you guys think, thanks for any guidance here. Tom <<You have my thoughts re, Tom. Good luck with the recovery. EricR>>

Bubble Trouble in Ca Reactor 3/31/08 I have a two vessel DIY calcium reactor made from instructions from this website. The problem I have is the Co2 bubbles stop working after a short time. <OK> I have tried opening needle valve from a closed position until I get, say 30 bubbles per minute and I have tried opening needle valve full open and closing until I get 30 bubbles per minute. In either case after a short time the bubbles stop flowing completely. <What kind of pressure do you have the regulator set at? It may need to be higher.> I have then tried to open the needle valve until the bubbles start flowing again and then as usual they will stop. I have repeated this process several times. Then what happened was something must have changed and a couple days later I go into my fish room and the bubble counter is running now wide open. Twice, I drained a 20 lb. Co2 tank!! Obviously that's a lot of Co2 to run into your house. <And/or your tank!!> I have tried different needle valves, three different bubble counters and three different check valves. I do notice if I open up the purge valve on top of the reactor I can increase the bubble count from nothing to a lot. <As it should.> I am feeding the calcium reactor with an IWAKI 70 pump that also feeds a ETSS skimmer it has a valve to adjust pressure , which I have tried with no improvement. The first chamber is re circulated using an IWAKI 40 dedicated pump as per DIY instructions, I do not have a ph monitor /controller on this calcium reactor. ( I do have one coming ) Any suggestions? Ron <Ron, I would start with the regulator. Try increasing your output from it to around 20 PSI. Then adjust your needle valve. This will likely allow a more constant bubble. Other factors to check and rule out: a leak anywhere in the system, inconsistent pressure from the feed pump, a dirty regulator and sticking check valves (although you tried three!). I hope this helps you track down your issue, Scott V.>

Re: Bubble Trouble in Ca Reactor 3/31/08 OK , thanks ,I have some things to pursue! <Welcome, it is a process of elimination.> I heard from another source to skip the bubble counter and rely solely on a controller to obtain the desired PH coming out of the reactor?? <This works, to a point. Your bubble count will still need to be close, the controller will just help you keep the PH of the effluent at a certain level. It will not solve the problems of bubbles going nuts or not bubbling at all. Good luck, Scott V.>

pH woes, need a calcium reactor adjustment? -12/14/07 Hi guys, This is my first time asking you questions, so I hope I haven't overlooked the answer in the research I've already done. If that's the case, then I apologize. <Apology accepted :)> Right then, here we go......... At work, I'm in charge of our coral system. I'm having some trouble with a low pH and have officially ran out of ideas! I'll try and give you as much info as I can. The total system volume is 1500 litres, and because of the position of it, it's basically set up as you would have a reef system at home (weir at one end, sump within the stand underneath). The tank itself has approx 200kg of live rock with the corals on colour coded stands amongst the rock. The sump contains some fine filter wool to remove particulate matter, a bag of UltraLith, aqua C protein skimmer, phosphate reactor, and calcium reactor. <The calcium reactor might be the problem (or part of the problem). Try adjusting the CO2 flow rate. Please see here: http://www.wetwebmedia.com/calcreactors.htm> I'm in the process of organizing Miracle Mud in there too. Over the last week or so I've got some fairly constant (as constant as you can get using additives!) water chemistry. S.G.: 1.025 NH3: 0 N02: 0 N03: <5 dKH: 11 P04: <0.03 Ca: 450 Mg: 1375 Now forgive me if I'm wrong (hopefully I'm not!), but I would expect a reasonably good pH with those results, <Huh? Why? You can have all those same parameters within pH range.> yet when I come in in the mornings the pH is around 7.95, rising up too about 8.05 at the end of the lighting period when I go home again. Do you think it could be any of the following? a) the fact that there is no sandy substrate in the tank, <nope> b) lack of water movement <This is a possible cause if consequently you have poor aeration.> c) lack of other inhabitants (fishes, etc.) <The opposite would be more likely-- if you had too many inhabitants, that could raise CO2 which can drop pH.> Thanks in advance! <Adjust your calcium reactor (carefully!) and see what happens...> R.B. <Good luck, Sara M.>

Cal reactor prob... and English    8/12/07 I just bought a MRC dual chamber and i am setting it for 3 days and there is always a problem that whenever i run the cal reactor, i have water coming through co2 connection nipple , <... need to increase the CO2 pressure... adjust secondarily with a needle valve...> then the water went up to the bubble counter and the bubble counter will fill up with water.... i don't understand what is going on? can one of WWM member help me solve this problem?... <Keep reading: http://www.wetwebmedia.com/calcreactors.htm and the linked files above. Bob Fenner>

Knop S-IV Air Bubbles Resolved! 5/2/07 Good morning all, <And to you, David.> Ok, so this isn't a question but an AH HA moment!  I posted my original questions here regarding gas block, and air being trapped in the reactor, and I received the right diagnosis that air was being introduced, but I didn't find the source until this weekend.  I'd chalked it up to an impure CO2 source after changing out the blue coarse filter pads and changing out the media, re-tapping all the fittings, and changing all the air lines and the CO2 tubing.  I even bought CO2 from another source, but nothing helped. Well, last week I move all my equipment and sump to the garage, and ended up plumbing the whole thing under my house which was no easy task, because it required 75 feet of both 2" plumbing for drainage and 1" for return, but that's another story.  Anyway, I ended up tapping my 1" return with a JG fitting to feed my reactor using 1/4 RO tubing, and changed the threaded fitting for the water input on the Ca reactor to a JG fitting as well.  After, 24 hours no more bubbles and it's now way more efficient!  I realized at that moment that the air was being slowly brought in from the siphon feed from the tank!  I never thought of that.. Doh! Anyway, I just wanted to share my experience just in case others are having the same issue.   You guys have helped me immensely in my success, I just wanted to give back in a small way. Thanks Wet Web Crew! <You're welcome, David, and thank you for sharing this information.  Will post for others to read.  James (Salty Dog)> -David    

- Calcium Reactor Problems - I have a Aqua-Medic calcium reactor 1000 for my 1000 litre tank, running now for approximately 6 months. In all the time it has been running it has never been able to keep my Alk or calcium stable at the required figures i.e. 7 to 10 dKH and calcium at 450ppm. I have measured the effluent with more than 2 reliable Alk test kits and it is reading  approx 14 to 15 dKH. I do have the normal coralline growth on the sides of my tank and my tank is about 40% filled with corals. The cal and Alk tests are always dropping to 4 or 5 Alk and 320 calc within a week of me boosting them with liquid calc and buffer. Please help me. <Well... a couple of things occur to me. First, it's time to switch out the media. In six months any benefit it might provide should be depleted if you've been adding the recommended amount of CO2. Next, you might want to increase both the drip rate of the effluent and the bubble rate of the CO2 and shoot for an effluent dKH reading of 6.7 or so. It is also possible that you are at the upper range of effect for this reactor - I realize it's rated for 1000 liters, but it may be that it works best on 750 liters of water. Lastly, and something that I like to always point out is that the dKH and calcium levels you describe are actually typical of most reefs around the world - there seems to be a fascination in the reef hobby of having these levels artificially high. You should use the growth of organisms that require calcium for their growth as a partial indicator of available calcium. If the corals aren't growing, then it's obvious there is a deficiency. If they are growing well and aren't brittle - then you are in fact adding sufficient calcium. All that being said, it's not at all uncommon to occasionally supplement calcium in a different form when using a calcium reactor, which produces calcium carbonate - adding Kalkwasser for instance, will add calcium via calcium hydroxide.> Kind regards Glen Cape Town, South Africa <Cheers, J -- >

- Calcium Reactor Problems - I seem to be the only person struggling with this, so I'm wondering if I'm missing something. I've read quite a bit about my Korallin calcium reactor and I believe I understand it quite well. While I found it easy to get the effluent drip rate consistent, I can not seem to get the bubble rate to hold steady. My process is this: 1) Set the effluent drip rate to about 40/minute 2) Adjust the CO2 pressure to 15 PSI 3) Adjust the needle valve to 10-20 bubbles/minute 4) Wait 15 minutes and tweak the bubble rate as it changes a bit over time. 5) Repeat step 4 throughout the day Invariably, I come in the next morning and either the reactor is about 1/4 full of CO2 at the top, or the bubbles have stopped altogether. The CO2 regulator has a solenoid, but it is not turned off at night or controlled (on 24/7). I bought a laboratory grade needle valve from Upchurch Scientific and it greatly helped the process of dialing in the bubble rate, but it still won't hold that rate overnight. My best guess is that somehow the pressure within the chamber is changing significantly over night and the change in pressure differential throws the bubble rate way off. But why some mornings is it off and others it is off and the chamber is full of gas?  <A very good question and certainly a bit of a quandary. My first impulse is to say there is a leak somewhere, but that doesn't explain the days that you end up with an excess of CO2. May also be the actual CO2, but then that doesn't explain the days that bubbles have stopped all together. I am curious though about the pressure... I don't typically run the CO2 at anything over 10psi, but I'm just not sure what the extra 5psi would do. You could try tuning this down just a bit and see if that makes a difference.  Likewise, I'd go over all your CO2 supply tubing to make sure nothing is wrong there and work the problem from that angle. I'm sorry I don't have a better answer for you but I've never run into this exact problem - what is more typical is a deficiency or an excess, but not both.> I must be doing something wrong. Have you ever heard of someone struggling to get a bubble rate to hold consistent for even a few days????  <Yes, but as I mentioned, what is most typical is a leak in the CO2 line which always leaves the reactor without CO2 at all... I wish I could figure out why you have both problems. You might also try a new check valve while you're at it.> I would greatly appreciate any help. Steve <Cheers, J -- > 

Knop C calcium reactor Hello WWM crew, I recently bought a Knop C calcium reactor and it seems to be missing the tube to feed CO2 to the bubble counter. Can I use a clear vinyl tube (bought from Home Depot)? It says it can be used for "gases" and can handle 55psi. Thanks in advance and keep up the great work. Sincerely, Aldrin <Mmm, am concerned re the CO2 "getting loose" here... you can likely use this vinyl tubing... but the more pressure resistant and carbon dioxide resistant (blue) tubing) is better, less likely to lose secure attachment, degrade with exposure. Of all people, my wife (Diana) used to distribute Knop in N. America and still has some of this tubing. If you'd like to contact her, she still maintains the knopproducts@hotmail.com  address. Bob Fenner>
Re: Knop C calcium reactor
Thanks Bob. I will be contacting Diana and see if I can have her send me a foot or two of the blue tubing. I set up the reactor last night with the vinyl tubing. Pressure dropped from 20 PSI to 18-17psi this morning. There's definitely some CO2 escaping somewhere. <Yikes... do leave some windows open, turn on, check the battery on your home carbon dioxide monitor... Or better still, turn off the unit. Bob Fenner> Thanks again. - Aldrin

pH Too High? (Nope) - 08/05/05 Hello, <<Hey>> I'm terribly sorry for bothering you guys, I know you are very busy and I appreciate all your help in the past. <<No worries, happy to help.>> I have a few questions regarding pH, I was actually wondering at what level I should start to worry if it is indeed too high. <<Mmm...would strive to maintain below 8.6>> I have a 180 gallon reef with 200 lbs. of aragonite sand, about 200 lbs. of live rock.  I use a sump below the aquarium and a 42 gallon refugium next to it that is filled with various forms of macro algae, live rock and sand. <<Suggestion...keep a single specie of macro algae in your 'fuge.  Algae competes for space just as corals do.  If they are fighting in your refugium they are releasing noxious chemicals to kill/retard growth of each other.  These chemicals will be/are affecting your display tank as well, not to mention keeping the algae from performing at its best as a means of nutrient export.>> On the 180 are 2x400w 20k halides and 2x110 15k VHO tubes.  On the refugium is 1x150 10k HQI and 2 65w actinics.  The sump is LifeReef design with 36" skimmer and carbon tubes.  I don't use any mechanical filtration other than the sponges in the tubes. <<Cleaned weekly I hope>> I use a Korallin calcium reactor with 10lb Co2 bottle with a fast drip and about 2 bubbles every 3 seconds (seems like a lot, but the reactor gets trapped Co2 in it, poor design I think). <<Hmm, have friends using this reactor...seem to like it fine.  I will assume you've already experimented with drip/effluent rates...measured pH of effluent.>> The system has been running for 8 months.  I've added animals slowly, I've had very few losses, algae is in check- I use a 6 stage RO and Coralife salt (and perhaps this is my problem) The source water (RO) is at pH 6.5, roughly, with an average of 5 TDS. <<Source water?  Do you mean the "effluent" from the R/O unit?.  Fairly normal readings, and a good reason to buffer all evaporation/salt makeup water.>> My ph, never falls below about 8.35 and tends to get pretty high during the extreme photo periods, I've seen 8.51 on occasion. <<Golly...these are actually quite "good" readings!  Many a marine hobbyist would love to be able constantly maintain pH values within these parameters.>> I use a controller with pH and ORP, ORP is never below 400 unless I do a big water change, at which time it dips 10-20 for a day or two, pretty normal I think. <<400 is not "normal" for most, nor necessary...would advise caution about going above this level.>> I've been toying with the photo-period on the refugium to make the pH more stable, but it still seems very high, is it dangerous at this level? <<A swing of less than .2 per day is not unstable...quite the opposite.  Your pH values are excellent in my opinion...would strive to maintain...>> My dKh is between 11 and 13, it hit 10 once when my Co2 bottle was empty and I had to wait to get it filled.  My calcium level is at 400ppm and I do not notice any animals being stressed, hard and soft corals do well, and the fish seem fine, algae is in check, present but acceptable. <<All good, but would not try to keep alk and calcium maxed out.  The two are mutually exclusive and can cause problems at such high levels if not carefully watched (do some reading here and at the associated indexes: http://www.wetwebmedia.com/calcalkmar.htm).  I would let one or the other drop a bit.>> So, I've read, actually in a number of places, that on the reef, pH during the day can hit this level, but I was wondering if it's ok and, if it keeps rising, why and at what level I should start to worry. <<As already stated.>> Should I cut back the light on the fuge, remove a large portion of the macro algae, or leave it alone? <<Other than the "mix" of macro algae in the 'fuge and the comments on your cal/alk, I think you're just fine.>> Honestly Baffled, Aaron <<Here's some informative reading on pH: http://www.wetwebmedia.com/calcalkmar.htm...not that baffling really <G>.  Regards, EricR>>

Calcium Reactor Question  - 12/07/06 Good Morning Crew! <Dave> I have a couple of questions regarding my Knop S-IV calcium reactor. The reactor seems to not be circulating the CO2 as well as it should, and therefore not melting the Korallith media. <For browsers this is the CaCO3 media by Knop>   How often should you replace the coarse blue filter pads that are at either end of the reactor? <Don't ever need to be replaced> Here's my situation, I've had my reactor set up for about 10 months now on a tank that was set up at the same time.  Other than 175 Lbs. of live rock in my 150 gal tank, and a few coral frags, I don't have much of a calcium load.  Animals seem fine, but for the first few months I was able to maintain my calcium and alk with a CO2 rate of 30 BPM, and a drip rate of 3 drops every 2 seconds. <With an effluent pH of?> I was using the larger coarse 6 -10mm Korallith reactor media.  My calcium was 390, and my DKH was 9 -10, and my ph was 8.2 - 8.3.  My effluent measured a PH of 6.7 - 6.8, <Ah, I see> DKH of 36 and calcium was 500    <Mmm, okay> After about 4 months I made an adjustment by accidentally to the needle valve, and had to go through the slow readjustment process, but I wasn't able to maintain the same levels as before.  I started off slowly with the same PH and drip rates as before, but the effluent still wasn't strong enough with a DKH of 16 -18 and a calcium of 450, nor was I able to maintain my calcium and alk levels overall.  I seem to deplete about 1-2 DKH/day and 25 or so of calcium per day, and the effluent levels weren't keeping up. <Mmm, four months? You very likely just need to replenish the media... or at least shake/consolidate and add to it> Now, after slowly adjusted the reactor to a drip rate of 5 drops/sec and 120 BPM of CO2 with a PH of 6.6-6.7, and changing the media grain size to medium (3-4mm) am I able to maintain my calcium and alk demand per day, but effluent DKH is still light (about 16-18 DKH), and calcium around 490.  My overall tank levels are 7-8 DKH, ph 8.10 - 8.20, ca 370, and nitrite, nitrate, phosphate = 0, <1, .4.    <This is fine... I would not change a thing here> I see lots of bubbles collecting underneath the blue filter pads in the very bottom and upper middle of the reactor, and there's a large bubble that collects under the lid at the top which seems normal, but don't remember ever seeing bubbles underneath the blue coarse filter pads. <This is most likely due to impurity/ies in your carbon dioxide... Nitrogen, Oxygen... less soluble... look to "higher grade" (more pure) CO2 next re-fill> It seems to me that the reactor isn't circulating the CO2 as well as it should. <It won't with air trapped in it> I've tried rinsing out the filter pads a couple of times, but CO2 still accumulates at the underneath side of the pads. <Not CO@... this gas is very water soluble...>   I've also tried turning the reactor upside down and right side up again the get the bubbles to interact with the media some more, <Good> but this creates a lot of precipitate to be free floating again, which in turn saturates the blue filter pads in the second chamber (CO2 filter).  I've tried just rocking it back and forth to get the bubbles to enter the pump which creates a lot of swirling bubbles in the pump chamber.  Something is amiss, can you suggest anything? <The CO2 purity> Should I try dropping the effluent PH to 6.4? <No, I would not>   Should I replace the blue filter pads or soak them in vinegar? <... you could, but unnecessary... I'd just rinse them off/out vigorously on the occasions you have the unit open> Should I try the fine reactor media? <Mmm, I would stick with, use the 10mm nominal diameter... 1082 call-out if memory serves... I've carried several tons of it about...> I just want to be able to obtain the same effluent levels I had when I first set it up.  I'm also waiting for ph regents so I can calibrate my Pinpoint PH probe just to make sure of my values.   Thank you, -David    <Do ask the gas service if they have other grades of CO2... I do believe this is your principal issue here. Bob Fenner>

Toxic tank, Contaminated Calcium Reactor Media    2/12/07   I have had toxic tank syndrome for 8 months now.  My pulsing Xenia starts to turn black in less than 24 hours.  All SPS corals had to be removed from my 180 gallon 5 year old tank.  Lost some fish, scooter blenny, mandarin, Rainford goby. <Yikes... so, what have you done re the toxicity?>     To make a long story short, I changed water like crazy, searched everything for a metal contamination.  Could find nothing, so I emptied the system completely.  Cleaned it all out, replaced the sand bed, all rock, everything out, and refilled with natural sea water.  After a week, I put a piece of pulsing Xenia in last night, and this morning the polyps were starting to turn black.     I got mad, again, and the only thing I had not done was to empty my calcium reactor.  I put the media in a bowl and searched it.  Using a magnet, I found small flakes of metal of some sort, laced through the media!!!!!!!!! <Yikes...>   I have not idea how it got there!  Not from me!  I won't mention a brand name here. <I wish you would... My wife, Diana, used to distribute Knop Products in N. America... their Korallith was/is very pure...>     I will do a 100% water change as soon as possible.  I can not afford to change the rock and sand bed again!  What further steps should I take?  Carbon?  Poly filters? <Yes to both of these... this should do it> Will my new rock and sand be ok? <Very likely yes> There are no fish or corals in the tank st this time.  All have been moved to other systems.   Help   Richard <Thank you for relating your experiences... Will save many others huge headaches and grief. Bob Fenner> - Calcium Reactor Adjustments - Hi Bob and Crew, I have had a KORALLIN C-1502 Calcium Reactor for about 4 months. It was purchased new. I have tried repeatedly to adjust it to the proper levels of CA and DKH. The Korallin web site is of little help as are their instructions. I have kept a log of my settings and results. They are as follows and my readings are taken 2 days after an adjustment. DRIPS    BUBBLES    CA     DKH 20            12    380    14.1   24            12    380    12.5 40            20    350    13.4 28            16    360    12.2 60            24    370    12.8 40            20    360    12.5 28            20    370    12.5 <I'm guessing the bubble numbers are per minute?> With most all of these settings except the lowest I get an air lock and must bleed off the CO2 every 12 hours. I don't understand how to create the proper adjustments as I can't get the CA above 380. Do any of you see anything obvious that I'm doing wrong? <Perhaps - I would be shooting for a rapid drip rate - about three drops every two seconds. CO2... probably best around one bubble every four to five seconds, but this is the adjustment I'd tweak. I'd get the water coming out the reactor as consistently as possible, and then adjust your CO2 to bring the pH of the effluent to about 6.7 - 6.8, and a dKH of roughly 16-17. After a week or two of this, you should see more consistent calcium levels.> I know it shouldn't be this difficult or no one would purchase this brand of reactor. I have a 110 gal. with soft corals and fish. Filter is a Euro-Fil-2 with the protein skimmer that came with it. The reactor media is only 4 months old. The media label says it's Korallin Natural CACO3 KTK ORCCM . Tank PH stays at a steady 7.9 at night and 8.0 at lights off. Effluent measures with a CA of 750 (if that's possible) and a DKH of 6.0 I am using a PH meter which is calibrated bi-weekly. Should I replace the media as none of my settings get me over 400 CA? If so do you recommend the brand A.R.M. Calcium reactor media or some other brand? <No, I'd use anything BUT A.R.M - just too impure for my tastes. I'd use the Knop Korallith - is very consistent quality.> Do any of you know if Korallin has a west coast rep? <I believe they are distributed exclusively by Bayside Aquarium which is in Anaheim.> Their web site makes no mention.  Thanks in advance, Dick <Cheers, J -- >

- Calcium Reactor Adjustments, Follow-up - Hi J, Good morning. <Greetings.> Again I want to thank you and the crew for all the help you give reefers everywhere. <My pleasure.> After this I'll give your suggestions a try and get back to you with the results in a couple of weeks. <Good, would like to know how it's going.> Korallin should ask you and your team to write an instruction booklet. :-) <Perhaps... but I won't hold my breath.> Thanks again, Dick <Cheers, J -- >
- Calcium Reactor Adjustments, Follow-up -
Hi Gang, I just noticed an error in my statement. My effluent measured CA 750 and a DKH of 64. Not the 6 as I noted.  Thanks again, Dick <No worries, but it does seem to me that you are trying to pump too much out of this reactor - again, you should shoot for something more in the range of a dKH of 15-17 on the output side of the reactor. Calcium will be more readily available to the system at this level. Cheers, J -- >

- Calcium Reactor Adjustments - Hi J, I have set my bubble rate and drip per your suggestions. I suspect that my tanks DKH is going to rise. <I don't think it will get too out of hand.> The weekend is coming up and I doubt anyone will be online. <Oh sure they will be, myself included.> If my DKH rises to 15 or more in the tank should I abort or keep going until it levels out. <Just turn off the CO2 via the solenoid... but I don't think you'll have much trouble.> What level of DKH do you think should alarm me to stop? <Over 15, 17 max... but this will depend also on calcium - keep an eye on both.>  Thanks again, Dick <Cheers, J -- >
- Calcium Reactor Adjustments, Follow-up -
Doctor J, <Hey, I like the sound of that... too bad I'm a white boy that can't jump like him.> Your info is working. <Excellent - glad to hear that I was able to help.> Thanks for the tips. So far my DKH has only risen slightly after 24 hrs and my CA is now rising. It's at 380 right now and I'm not having to bleed off excess CO2. Will check again tonight. <Sounds good.>  Thanks for everything, Dick  <Cheers, J -- >

S-IV reactor Diana, I emailed you yesterday and have not heard back from you.  I do have a quick question about the reactor.  Is the internal bubble counter subject to the pressure that builds up inside the reactor?  I have a new dual gauge regulator setup with a very expensive needle value, and no matter how hard I try the bubble rate will not settle down.  I can set the rate to say 25 bubble per minute, and twenty minutes later the rate has changed, it will go either way, up or down, but never stays the same with your supplier.  You can't set the reactor up without having a constant bubble rate.  Is it possible that this reactor is more damaged than I first thought?  Have other customer complained about this problem?  I need a response quick as I am trying to make a decision about whether to keep this reactor, or send it back to Marine Depot for a refund.  I assume since I haven't heard from you that you haven't sent the check out.  In either case If we can't solve this problem, I will simple return your original check, as I would never cash the check if there was a problem.  Regards, Tim Roberts <would first switch out your needle valve here, the tank pressure and flow through your regulator are very likely static (fine). Bob Fenner> Hello... JasonC here. Have seen this problem before and is typically caused by a leak in the CO2 plumbing... either a crack in the tubing, a leak in/near/around the regulator - if it has it's own bubble counter, this is a common place for the leak to occur. Would examine all these things closely... between the CO2 tank and the reactor all those fittings need to be air tight and plumbed with CO2-proof tubing. Cheers, J --

- Calcium Reactor Problems -  Jason C, thanks for the reply. <My pleasure.> When I replaced my old gauge set with a new set, a set with a working pressure gauge which goes from 0 to 15 PSI (why old one went from 0 to 150) , I noticed that the pressure on the gauge would continually drop. <Sounds like a leak somewhere...> I set the gauge five times last night. I would set the working pressure to 10 PSI, and a few minutes later the gauge would read 8 PSI, so I would readjust. I am thinking I have a hairline crack in the tank valve. <Or somewhere close...> A leak in the gauges, or after the gauges would not effect the working pressure. <Actually, the working pressure is somewhat reliant on back pressure in the rest of the 'plumbing' between the CO2 supply and the reactor... have seen this exact behavior caused by a crack in the CO2 proof tubing which is not infinitely elastic - can be cracked by stepping on it or too tight of a turn radius.> Remember I have had this same problem with two different gauge sets from two different manufactures. <All the more reason to make sure you don't have a problem in the lines.> The odds of having two regulators, both defective, with the same problems, are really small. What do you think, am I on the right track? <Perhaps... would be diligently checking in all possible places, not just the ones that make sense.>  Thanks, Tim  <Cheers, J -- >
- Reactor Trouble, More Follow-up -
Jason, thanks for your help.  I am not trying to disagree with you, I am just grasping for straws to get the reactor to work. <No worries.> The air line I used is supposed to be CO2 safe, however, I will replace it with some tubing that came with another reactor I had.  Please don't misunderstand me, you are the expert, and I appreciate your time. <I am hardly an expert... everyone's experience is different.> I didn't get the instructions or the tubing that was suppose to come with the reactor. <Bummer.> Diana is sending them to me this week. <Excellent.> Thanks, Tim <Cheers, J -- >

- Calcium Reactor Problems - Hello Robert, <Hello, JasonC here in his stead...> I bought your book "Conscientious Aquarist" and enjoy it very much. Recently set up a DIY calcium reactor and had a few questions.  Was hoping you might be able to provide some guidance or refer me to a site for advice. <I will do my best.> Questions: 1.)  What's the normal break-in period and what exactly does that mean? <There really isn't one - what is breaking-in is you - getting used to how the various adjustments work in conjunction with your tank.> 2.)  Seem to be having difficulty getting effluent PH to drop below 7.0 with CO2 rate at about 15-20 bubbles per minute and effluent dripping too fast to count, but not streaming.  Is this related to a break-in period or do I need to increase CO2 or decrease effluent rate? <Either but not both - I would leave the CO2 as it and reduce the drip rate exiting the reactor.> 3)  Are these reactors supposed to work under some pressure? <Only the smallest amount.> seems by adjusting input rate and effluent rate, it will eventually equalize anyway. Yes/no? Does pressure affect amount of dissolved CO2 in the chamber? <Yes.> 4)  Measured calcium level of effluent and it seems to be no higher than the water in the tank itself.  I expected to see a much higher level.  Suspect this is related to PH level in chamber not being low enough to dissolve media.  Correct? <Correct.> In essence, how do I get this thing tuned properly and how long should I expect this process to last. <Please read an article I've written about this exact topic: http://www.wetwebmedia.com/calcreactors.htm > Starting with low calcium levels in the first place about 260.  Could this have something to do with it?  Tank PH ranges from about 8.0 to 8.2 using Pinpoint monitor, temp ranges from 76.5 to 78. Not much in the tank, other than live rock, live sand, some cleaner critters and a lone Yellow Tang.  About 220 gallons including sump and refugium. Want to get things just right before adding any more critters. <Do read up.> Thanks for your help. Regards, Julio South Florida <Cheers, J -- >
- Calcium Reactor Problems, Follow-up -
JasonC, <Hi.> Thanks for the feedback and article. <My pleasure.> See below. <Ok.> Well, I finally have this thing tuned and, I think, working properly. Bubble rate of about 40 per minute and effluent rate of about 60 per minute results in an effluent out of the second chamber with calcium level in excess of 500 ppm and alk of about 16. <How about the pH of the effluent?> Both of these are at the maximum ranges of my test kits.  So I feel good about where I am at this point. On the other hand, I'm confused.  After about two weeks of the reactor running 24/7 at the above effluent parameters, I've seen no change in the calcium level of the tank (about 270 ppm). <It's going to take a little longer than just two weeks to actually see this thing bear fruit.> Alk/dKH has gone up considerably from about 8 to just over 13, but calcium level isn't doing anything.  Any thoughts? <Patience.> Magnesium level is about 1200, which is a bit low.  I've read this can influence the calcium levels. <It can.> So here are my questions: 1. Do you think Magnesium at 1200 is the cause of my problem? <Not necessarily, but could be the result of the media you are using in the reactor. A good media will help supplement this.> 2. Do calcium reactors have the ability to raise already low levels of calcium, or do they simply replenish what is consumed by tank inhabitants? <Depends on how it is adjusted and sized to the tank.> I only have live rock at this point in time. 3. Is the high Alk/dKH now part of the problem? <It's a limiting factor, but the byproduct of the calcium reactor is calcium carbonate so there should be a good amount of calcium about. You might want to try another test kit.> 4. Where do I go from here? <Forward, onward.> Yours truly going insane, <No worries.> JT <Cheers, J -- >

- Calcium Complications - I have had a saltwater tank for over 10 years. It has been an up & down battle all 10. I recently decided to go for it and purchase some good equipment. New Hamilton Protostar 4' light. 2 x 250w HQI & 2 96w 7100K power compacts. I made my own calcium reactor that is working quite well.(3"x20") I just added Korallith media to it (removed old media) because I was getting such a high KH 28.8 PH 6.8 calcium 460 out of the reactor. Now, with the Korallith, my KH is off the scale calcium 460 PH 6.7. I am using Salifert test kits, brand new. Bubble rate co2 1 every 4 seconds, drip rate 1 drop every 2 seconds CO2 shuts off with the lights. <I'd increase the drip rate out of the reactor - perhaps two drops every three second.> I have had trouble getting a consistent drip rate, any ideas on a good valve? <Probably not the valve but calcium precipitating on the tip of the valve - turn down your CO2 for a little while, let a little more water out of the reactor.> I'm getting frustrated. <Well... try to save it for later, calcium reactors generally take a good deal of adjustment before they work just right.> From what I have read, there is no way that I should be getting these kind of numbers out of this set up. <Oh no... it's very easy to produce these results - your reactor needs more adjustment.> I have gotten the drip rate up, but the PH out of the reactor goes up to 7.0 or higher. <That's OK.> Why is my KH off the scale? <Because calcium reactors are really alkalinity reactors, with calcium being a by product.> My tank PH is 8.1 during the day, 7.9 at night. I have new PH controller, regulator with solenoid valve. All of this equipment is new. The reactor is working great. It can pull the co2 all the way down through the pump. I have a couple of the SPS frags that are going down for the count. Others look good, but little if any growth. I have some LPS coral that are doing good, and My leathers are OK too! I do have some coralline popping up, most of my tank was void of it before I started the reactor. I have had troubles keeping the PH up. Things are better but this off the scale KH has me bothered. <It should be expected - what is the alkalinity of your tank - that is the more important number.> If the KH is this high, My PH should not be a problem? <Could be other items - perhaps dirty gravel/sand pulling down the pH - look for all possible sources.> I think that I am also getting SNOW. <Then turn off the reactor for a while - run a full round of calcium and alkalinity tests on the tank - this should be telling.> White yuck laying around the tank. I change 4 Gallons of water every week to try & keep it under control. 70 gallon tank, 10 gallon sump, chiller set at 80* heater at 78*, protein skimmer, small NNR in the sump. My nitrates are zero, I quit testing it because it has been zero forever. RO/DI replacement water new setup) Instant ocean 1.024 SG. What's up with my reactor????? <It needs more adjustment from you.> Jeff <Cheers, J -- >

- Bubble Counter Problems - I'm having a problem w/ the bubble counter on my reactor filling up w/water. Water is dripping in slowly but is coming in from the reaction chamber. This is apparently an older design of the bubble counter as the input and output are both on top. What can be done to stop this? <The only time I've seen this is when there is a leak and/or lack of pressure in the CO2 supply to the bubble counter. Most often this can be observed when power is lost at the solenoid and the CO2 supply is cut off. I'd make certain your CO2 regulator is set to about 10 lbs and that there are no leaks in the CO2 supply.> I only need it 2/3 full and it's completely full as is. I also have water dripping out of the top. <Should probably remove this fitting and put some pipe tape on it - any leaking at all in the CO2 supply to the reactor will cause problem similar to those you describe.> Your assistance would be much appreciated. Thanks. Sincerely, Mike <Cheers, J -- >

Low pH, high CO2, reactor design/maintenance Hello, <<And hello to you.>> I have conversed with Mr. Calfo in the past about my low PH in my 180 gallon saltwater aquarium. I am very pleased with his help and straightening my situation out. My problem with my low PH still remains though. I just installed a Knop C calcium reactor two weeks ago with much frustration because of the large bubble of CO2 that kept getting stalled at the bottom of the chamber just below the blue sponge and under the PVC plate that it sits on. This would in turn stop any and all circulation of water through the calcium reactor. I finally figured out how to solve this bad design flaw. <<Ack! This is not a design flaw, you are simply pumping too much CO2 into the reactor in relation to the amount of water coming out of it. The problem you describe can be caused by three things which all work together, one - weak supply of feed water, not enough pressure. Two, slow drip rate out of the reactor, and three which works in tandem with number two, too much CO2 coming into the reactor. I've been running a Type-C for many months without this problem or modification.>> I took the reactor apart and had to forcefully pull out the round PVC plate that was in the bottom of the reaction chamber and shorten the PVC stand that it sits on by 3/4" of an inch so it now sits approx. 1/4" above the inlet tube to the Eheim pump. Any bubbles get sucked through and all was now running very well with no problems with the bubble under the blue sponge anymore. <<Fair enough...>> So after tweaking and fine tuning and reading through your web site I decided to install, inline, another reaction chamber to the Knop C that I already have. If I understand you guys correctly the second chamber is just another chamber after the first where the effluent from the first runs into the second from the bottom of the 2nd to the top where it then drips into the tank? Is this correct? <<Yes.>> I used a chamber from a used Kent 24gpd RO/DI unit that I had laying around that I was doing nothing with. It works rather well but the effluent still is only approx. .16 higher coming out of the 2nd chamber into the tank. The effluent out of the first is at 6.72(ppm?) and the PH of the effluent dripping into the tank from the 2nd chamber is 6.88(ppm?). Does this sound reasonable? <<sure.>> I am still a newbie to the calcium reactor thing. My alkalinity in the effluent is 14(?). I don't know if that's dKH or KH or what? I use the SeaTest kit from blue to green and get 14 drops. <<So the test should tell you what it is measuring - probably dKH.>> My effluent calcium the last time I checked was 320ppm using Salifert test kit. I use a Hanna PH hand held tester for the PH. My system PH will not come up above 8.15 during the day and tonight it was at 7.88 the last time I checked. My system alkalinity is a constant 12 with the calcium reactor running. The only way to get my PH above 7.9 during the day or night is to add Seachem Marine Buffer on the order of 3-4 tablespoons in a tall glass of water mixed for about 5 minutes.  <<Well... you have some compelling reasons to not be running a calcium reactor at the moment. If you were having pH problems before, the reactor and all it's various modifications isn't going to help at all. I would carefully examine your system to determine why it is so hard to keep the pH up - do you buffer the water you use for top-off? Do you have a sump with photosynthesis going on? You could move this to reverse-daylight time to help boost the pH at night. A favorite of Anthony's is to do small Kalkwasser additions [naturally high pH] first thing in the morning. You have many options, but running a calcium reactor, who's effluent is by design always below 7.0 is going to give you fits. Consider tackling the pH problem first... if you have calcium-hungry occupants, supplement with a two part solution until you get the pH under control, then go back to running the calcium reactor. Cheers, J -- >> 

Clogged Knop reactor check valve > Hello Daniel and all, > Any suggestions for unclogging the check valve on the bubble counters that come with the reactors? I was thinking of a soak in some Muriatic acid. > just Joe > Reefkeepers mailing list > Reefkeepers@seaplace.org > http://www.seaplace.org/mailman/listinfo/reefkeepers Joe, Those check valves cannot just be cleaned by soaking in an acidic liquid. It's a very sensitive membrane device opening at a pressure of 2 atmospheres. If the valve has already functioned before, it should not fail, they normally work "forever" and are very reliable. But if it has not been installed yet and did not work yet, it might be a "lemon". Whatever, just contact Diana Fenner and she will send you a replacement free of charge. Only make sure that the test for function was not just a person blowing into the valve, because it is definitely impossible for a human to blow with that pressure (most of the check valves being sent back to us as a malfunctioned unit have been tested this way and work perfectly ;-) Just contact Diana and she will solve the case. Right, Di? Best regards, Daniel

Calcium Reactor Woes Hi there guys, whoever is helping today. <Anthony here in your service... > Here is my dilemma with my calcium reactor. I have a 45g reef tank, with 1 175w metal halide, 2 28w actinics and one custom SeaLife PowerQuad with 96 watts, which brings me to about 7 watts per gallon. I have some pieces of Acropora and other hard coral, a few softies and 4 clams. I was getting tired of dosing part a + b of whatever calcium so I bought a K2R reactor with Carib sea arm media. After about 1 week I build a nice second reactor to bring the pH back up a little before the effluent drips int a small container that overflows into my sump. I keep my effluent at pH6.8 via controller. My dKH is way off the chart, around 22dkh.  <whoa!> In the effluent it was around 45 at first, <Biggie-sized Whoa!> Then I started to set the effluent to more flow instead of dripping it, <hmmmm?> and the effluent dKH came down to around 30, still no change in dKH in my tank. <too much bled in at fist and unused> Calcium in my tank does not seem to rise because of high dKH. It is only around 250 to 280 at best. <indeed, the calc/alk ratio is skewed> effluent calc is around 300 to 350. I am at a loss here and want to know what else I could do. I don't want to dose anything, but I do dose calcium to keep the levels up a bit. My questions are, how do I get the dKH lower, I did water changes and top off with ro/di water, <Agreed... dilute the dKH with a large water change but follow up with a slower drip through the reactors...any flow described as a stream rather than a drip is too fast. Also, you may use Calcium Chloride (liquid calcium/turbo calcium dry) briefly to get your calcium up to a more traditional level (after the water change and drip adjustment...even 350-400 would eb great at this point.> but I don't know what else I could do. The system has been running for about 4 weeks and no improvement in calcium. I have to say, my corals look great though, my clams seem happy, not me though, I want the calc up to 450, the dKH to 12. <simultaneous high end levels of calcium and alkalinity are not realistic for most systems...in gross terms they can even be mutually exclusive (causing crystalline precipitate "snowstorms" of which you are at dangerous risk with your high dKH> am I getting impatient too soon or are there any tricks.  <quite frankly, you either didn't get good directions with your reactor or you didn't follow them. You streamed too much carbonate into your system and it will take some serious dilution to get it down. Imagine if your dKH was 24 and you did a 25% water change... even with demineralized water (dangerous!!!) you would only bring it down to 18 dKH, and so on... It will take time and dilution. The effluent water should exit at the rate of a drip and not a very fast one at that> Magnesium is around 1350. I know I can't keep the dKH that high for long, but I don't know what else to do. I appreciate all your help and I am glad that Bob has great friend that are willing to share their knowledge with us. Please tell Bob I said hi and I am still waiting for him to come to Los Angeles to get his free haircut (he knows what I am talking about, hahaha). And if you guys are in town same offer to you, the least I can do. <Wonderful<smile>...and thank you!> By the way, I will probably go to Interzoo in may, since I have to go see my parents and friends anyway, and that's where I grew up for 25 years, in Nurnberg. My parents live about 2 minutes away from the convention centre. I hope to meet you guys there, I'll owe you a few beers for all the good advice. SASCHA <Bob, indeed will be going... but alas, Steve and I will be back here helping to run the site. But not for a lack of gracious invitation by Bob. I will look forward to sharing some food and intoxicating libations in LA with you. Kind regards, Anthony>

Alkalinity and pH Control Bob: <Steven today.> Recently I purchased a large calcium reactor secondhand from a local marine store (MTC Pro-Cal). I set it up on my 58 gal. reef (small in size compared to the reactor's capabilities!). I had it running for a couple days with very low input into the tank in order to avoid a sharp change in pH. However, within a couple days I noticed that most of my soft corals had closed up, with one torch coral looking like the tips had been burnt off! I also noticed a dead shrimp and some snails that were not moving, starfish with holes (lesions) in them, and mucus sloughing off the corals. My purple Montipora bleached out in a day. I am afraid I have done irreparable damage to the tank inhabitants. The catch is, I cannot determine the exact cause. The fish have not been affected. I did a partial water change with little improvement to the inhabitants. At the same time that I started the reactor I also added a product called "Stop Parasite", because of an Ich outbreak. The manufacturer says this product is completely safe for reef aquariums, and it can be added directly to the aquarium. I only added one dose (less than 1 teaspoon) and stopped because of the reaction of the corals. [By the way, would a UV sterilizer be the best method for eradicating Ich?] I placed activated carbon back into the sump. In any case, because these two things occurred simultaneously, I am having difficulty assessing which one caused the problem. I have a pH monitor on the tank. I noticed the pH range to be between 7.9-8.2 (could have been a time I didn't noticed a dramatic drop, but I have been adding more buffer in the hope to preclude a swing in pH). I just measured the alkalinity in the tank and it seems to be good (4.0 meq/L or 11.2 dKH). Could a dramatic increase in alkalinity cause this type of reaction of the invertebrates? The alkalinity in the tank before I set up the reactor was around 2.0 - 2.5 meq/L. As a note, I haven't calibrated the pH meter since I bought it (I know, a bonehead move). I will do so shortly. <Your information about pH is completely useless when measuring with an uncalibrated machine. It is utterly impossible for me to say if the readings are accurate, significantly lower, or higher than the numbers you gave.> Do you know anything about this "Stop Parasite" product that is supposed to be so safe in reef systems? Aside from purchasing a UV sterilizer (another expensive purchase), I have tried unsuccessfully to get rid of Ich in my tank. Could a dramatic swing in alkalinity cause an "acid-like" reaction where the corals and other invertebrates appear "burned"? <I do not know which caused the problems in your tank. Whenever first hooking up a calcium reactor it is imperative that you watch the calcium, alkalinity, and pH very closely for the first several weeks until you have the unit dialed in correctly. Secondly, I would not use any Ich medication on a reef tank. It is much better to quarantine all new arrivals prior to putting them into your main display. Unless, the Ich broke out and you have not added any new fish for several months. Then you may have even more problems.> Thanks for your response. Tim <With more and accurate information, perhaps I can be of more assistance. -Steven Pro>

Bubbles of CO2 Hello, Bob For a long time I have been observing the accumulation of bubbles on the rocks in my 125g tank. In the places, where there bubbles gather, <I'd say, "coalesce"... gasses always forming, dissipating... but under some conditions...> coralline algae stop growing and brown algae, which aren't slime algae <Actually, very likely this is a or a mix of blue green, aka slime algae, aka Cyanobacteria... Got a microscope? Have some micrographs, explanations of how to discern "real" algae from BGA on the site: www.WetWebMedia.com under the term "BGA".> and tightly stick to rocks, appear. What can I do to stop it?  <See the above citation under the Marine Index... not hard to turn the system in your favored direction> Calcium level is high, about 460, kH - 8, pH - 8,2-8,4, NO3-0, PO4-0. I use the Aqua Medic calcium reactor. It's set for approximately 60 bubbles of CO2/minute and 60-70 drops/m of the effluent. The reactor is filled with hydrocarbonate. As I have two Tunze pumps (1 pomp- 2400l/h), gas exchange ought to be good.  <Your readings look good... but... oh, I see the question coming below> Is it possible that it is the excess of CO2 that creates bubbles? <Yes... do you know the pH of the effluent? I would not have it lower than 6.9... and would (among other things... like using a lighted sump, macro-algae...) cut back, reduce the amount of CO2 bubbling accordingly... and maybe look into more soluble carbonate source. A softer aragonite might be better> I do partial changes of water (RO) every two weeks (10%). I would be very thankful for your advices. With regards Krzysztof Tryc Poland, Warsaw http://www.astercity.net/~lumen <Please look over the site, measure the pH of the effluent, reduce the input of carbon dioxide... The bubbles are not CO2, but from driven metabolism of organisms in your substrate. Bob Fenner>

Calcium reactor effluent Mr. Fenner I hope you're fine. <Yes my friend, thank you> This time I ask you for a comment...advice, about a fact concerning my calcium reactor. -The reactor effluent comes out through a 5mm. int. diameter flexible plastic tube with more or less 5 cm length. If I collect and measure the liquid PH at this point, let's say I obtain a 6.7 value. <A little low... would keep at 6.8 or slightly higher> -In my system, that tube extends about 1 meter and drains in the sump. If, at the same occasion, I measure the PH in this point, the value is 7.4 -And..... again at the same occasion, the PH inside the reactor is 6.5 <Okay> Is the lost of CO2 during the tube passage the cause of this PH increase ? <Largely, yes> If yes and if it is something to avoid, should I short-cut the tube? For me it's easy making drip the CR effluent in the refugium ( macroalgae) or in the 25 liters recipient that contains the skimmers. All of this recipients are draining in the sump. <Hmm, yes, better to cut, run the tube shorter... better still to make sure the effluent has maximized amounts of biomineral dissolved in it... I would slow the bubble count down a bit, recirculate the mixed water in your reactor contact chamber if this is possible in your make/model of reactor...> For water changes I use fresh and clear.....macroscope!..... natural seawater. What can I do in order to minimize eventual mal-effects ? <Store in the dark, make regular water changes after it's stored a week or two... and possibly add a bit of buffer to it... If it were mine, I would be tempted to just use synthetic water...> I appreciate very much your opinion about the described issues. <Glad to help. Bob Fenner> Best regards and thanks Flávio Ribeiro

Thanks for you help Mr. Fenner, <Call me Bob> I just wanted to update you as to the problems that you helped me solve in my 300 gallon reef tank...and to thank you for the assistance. <Okay> I asked for help with my shy Copperband and my Cyano-bloom and you were absolutely right on ! You told me that in time the butterfly would come around and he is now eating frozen food as well as grazing over more of the tank. Now he is my most beautiful fish and he actually comes to me for feeding now....a long way from that beaten up, ulcerated fish i bought a half year ago. I am so glad he is healthy and happy and that he is not hiding anymore. <Me too> Then you told me NOT to use antibiotics for the Cyano. Instead I just turned down the CO2 feeding my calcium reactor and the Cyano is almost gone....I am also in the process of acquiring Caulerpa and other good algae to plant in my sump along with a reverse lighting schedule from the main tank (I will hopefully get some time this weekend as long as the wife doesn't have any plans for me !).  <Yikes...> Hopefully this will give me a more constant pH and will keep the nutrients low so that i can avoid another bloom. <It will my friend> My tank looks great without all of that Cyano and my gorgonians are lot happier. Thanks again ! Chuck Spyropulos <Very glad to hear of your success. Bob Fenner>

Low pH using Calcium Reactor Hello Bob, We have a 150 gal reef tank with a 40 gal sump (1/2 of the sump is a refugium). <Good size, idea> We purchased a Knop HD Calcium reactor using Knop Korallith media about 2 mo. ago and just recently have seen an increase in the calcium level (in tank and effluent). However, the pH in the tank is very low. It ranges from 7.94 to 8.08.  <This is not "very low"... indeed, it's higher than most places on the world's reefs...> I've read in your emails to others to keep the effluent pH at 6.8. We've been keeping the effluent pH between 6.3 - 6.4 to keep the Calcium level in the effluent over 600, which we were told it's supposed to be.  <Not IMO> We had the effluent pH higher, but that resulted in a lower calcium level. Our calcium level in the tank  now is only 350. We realize the low effluent pH is keeping our tank pH low.  <Yes, likely> We have the bubble count high approx. 130/min, water flow is 3l/hr, alkalinity is 5.5. Our corals look  great and the xenia's are spreading like wild fire, but I don't think they'll survive long with such a low pH.  What can we do to get the pH higher and to maintain a high calcium level as well? Thanks in advance. Sherri <This may seem like a simple to the state of flippancy suggestion (it is not), but do just look into and use  a more suitable material to "melt down"... There are a few other possible "issues" at play here (resultant mis-interactions from concurrent or "old" use of supplements, a proportionality problem  with another alkaline earth material (Magnesium)... but do just look into... Aragonitic materials, like  CaribSea's... and give them a go. No intention/need to be mysterious here... these are composed of  different mixes of biomineral and alkaline materials... some more soluble than others... Next, if this doesn't do the "trick" for you, we can discuss the use of expedients like baking soda... other adjuncts. Bob Fenner>

Calcium Reactor/algae Hello Bob, I have now had a calcium reactor on my 30 gallon mixed reef for about 4 plus months. During this time I haven't added anything other than PhosGuard biweekly with 10% water changes. The corals look great and coralline is growing rather well. But green hair algae is growing like crazy! I had a problem with this before (prior to having a calcium reactor), and was able to clear the tank of it. Although I have noticed that the green hair algae I had before was long and stringy, where the green hair algae now is short, and looks like tuft's of hair. I use Knop Korallith media, and originally had my effluent PH running around 6.3-6.5 for the first month. After speaking with you I started keeping the effluent PH around 6.8, but still no change in the green hair algae's growth. I use only RO water and I keep lots of live rock, hard and soft corals and clams with 4 small fish and a Algae Blenny. Also keeping many small crabs and shrimps, including 4 Emerald crabs.  <An algae blenny and four Mithrax in a thirty... should be enough...> I feed maybe a pinch of San Francisco Bay Brand, Sally's frozen brine shrimp every 3 to 4 day's, and have even gone almost 2 weeks without feeding, and still green hair algae grows. I run three 36in VHO lights 2 white, one blue, 9 hours a day. I have tried many times to keep green macro algae, but my Tang and Emerald's devourer it, and I had no luck with it in a (24hr lit) refugium/sump. Could you please help me in figuring out what the problem is here. <No luck with a refugium? Would like to know more here... a hang on type? What happened?> Your knowledge and patronage is always appreciated. <As are your kind attentions and input... You are doing about all I would/do .. you're not adding anything else? I would use activated carbon once a month... Bob Fenner> Thank you, Rob

(DIY) Calcium Reactor Questions 1. If you over drive your calcium reactor does the excess calcium precipitate on the water surface or attach to everything like Kalkwasser drips? <Mmm, some calcium reactors, various feed stocks can be made to do this... but not practically> 2. What is the maximum saltwater can hold? <The maximum what? Calcium? Several hundred ppm.> 3. Does salinity (1.019) or water temperature (76-80) play a significant factor? <In saturation, introduction of biominerals (alkaline earth elements)? No, not "significant" in hobbyist/husbandry terms> In preparing for a larger main tank I have built a six foot tall calcium reactor.  <Six foot tall? Unnecessary. Was at a local marine club meeting a few days back just to give you an example. The owner had a 1,200 (twelve hundred) gallon system with a two foot high Knop unit...> Poured 50 pounds of Geo Marine in it then I pushed the affluent <Is it rich? Effluent likely> PH down into the 6.5s while maintaining a fair water flow. Within 24 hours I now have what feels like sandpaper grit accumulating on the water surface in the sump. Is this related? <Yes> Fish seem OK. Has anyone else felt this on the water surface? Sump is in the garage. Will this turn my plenum into cement? <Don't know about the latter... but you don't need, want this much feeder stock, this low a pH effluent... Experiment a while... perhaps on a non-living set-up. Bob Fenner> Thanks, Steve Heathcote

New Calcium Reactor hi bob, or j (if your still filling in) <<JasonC here...>> my calc results after a week are ok i guess; calcium 420, but alk is way high (14+), and ph is quite low (7.9-7.95). the fish are fine; corals looks like they're adjusting (not opening up occasionally, etc). actually; my leather hasn't opened up since i started using the reactor (due to low ph? it used to be 8.2). <<a possibility, yes.>> is this what I'm looking for in a steady state? do i just give the animals time? <<well, I would definitely be at work trying to get that pH back up.>> my concern is that my alk is already high, so ph probably wont rise much if at all further? should i be concerned with the low ph? <<yes>> my effluent is ph 6.86-6.91, AquaMedic using the included hydrocarbonate. your opinion is appreciated. thanks, <<would try the Baking Soda regimen to see if this will help the buffering in your tank. Something is definitely amiss.>> Javier
<<Cheers, J -- >>

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