high alk?

[safeuerwehr]

i started a calcium reactor two days ago at that time my ca was 320 and my alk was at 10 dkh which was no cause for alarm as i have read this is some what a normal reading....yesterday ca was 400 and alk was 25 dkh....so i read that alk will come down on its own but not sure if i need to take immediate action to bring it down as today i test and the alk is at 24 dkh....I am also dripping Kalk to keep ph stable....LMK is this is ok or how to reduce alk.....

[GaryP]

Wow, what a bag of worms!

OK first, the term calcium reactor is a bit of a misnomer. It would better to call it an alkalinity reactor. It produces more alkalinity then it does calcium, as is obvious in your case.

Next, alkalinity will fall a lot faster then the calcium level so I would just suggest turning it off and letting it come down on its own.

Third, the kalkawasser is not needed and is actually probably careful for a couple of reasons. With your alkalinity that high you shouldn't need to worry about your pH until it gets a lot lower. On top of that, Kalk actually produces more alkalinity by neutralizing CO2. And finally, raising the pH with Kalk can cause precipitation which will just drop your calcium and cause your system to be even more out of balance. Just leave it alone for a week or so. If you want to do anything, I would suggest a water change to help things along. Calcium carbonate loses its solubility in water, the higher the pH is. So unless the pH is drastically low, I would leave it alone.

Lastly, you obviously had your reactor turned up to high. I'll let someone else that is more of a reactor wizard then me (Matt?) help you with that. I do think that when you restart it slowly and that you need to adjust it upwards to maintain the proper alkalinity and then fine tune the calcium with something like Kalk to help maintain pH and calcium or turbo calcium just for the calcium level.

In theory, and if the reactor is working to completion of the reaction, you are supposed to get 2 parts alkalinity, for every part of calcium:

CaCO3 + CO2 + H20 ----> Ca + 2 HCO3

HCO3 (bicarbonate) will not boost your pH. That's where Kalk (CaOH2) comes in. It converts HCO3 to CO3 (carbonate).

2 HCO3 + CaOH2 -----> 2 CO3 + Ca + 2 H2O.

Kalk also neutralizes CO2 (carbonic acid - H2CO3).

CaOH2 + H2CO3 -----> Ca + CO3 + 2 H20

I think that a lot of people assume the reason they get low pH from a calcium reactor is excess CO2 (carbonic acid). They may be part of it, but I think a larger part of it is a low carbonate to bicarbonate ratio. A buffer system is made up of two ingredients, an acid and a base. In this system, bicarbonate is the acid (lower pH) and carbonate is the base (higher pH). If the majority of your alkalinity is in the form of bicarbonate, your pH will be low.

[safeuerwehr]

your exactly right gary...i did have it full flow for about 12 hrs...until i read that it should be at a slow drip....so hench the high alk....but it is coming down and i have adjusted it down to where it should be....but i will shut it down and monitor the levels....but for now should i try to bring the alk level down?

[GaryP]

I edited my above post. Check it out. I would leave it alone for now, or maybe do a water change to help the alk. level adjust faster. Keep a close eye on any shrimp or crabs. Crustaceans are supposedly sensitive to big swings in alkalinity. According to Instar it has something to do with their eye stalks or some such.

[GaryP]

Let me correct myself. I did some research and found that I made a mistake in something I said earlier.

A pure solution of bicarbonate actually has a pH of 8.3. Now what we have in the aquarium is not a pure solution by any means, but when the pH gets below 8.3 that means that the equilibrium has been shifted towards carbonic acid. There are also other buffers involved in seawater pH such as acetate and borates. However, the carbonate/bicarb/carbonic equilibrium is what does most of the work in regulating pH. These compounds shift hydrogen ions back and forth and thus try to maintain a stable pH.

A buffer can be thought of as something like a rubber band. It resists a pull in either direction and tries to snap back to the middle. In our case that is in the 8.2 to 8.5 range. Typically, the bicarb to carb ratio in seawater is 6:1. The carbonate balances out the carbonic acid and thus the pH is maintained around the pH of bicarbonate. These compounds all exist at the same time in an equilibrium. Whenever more CO2 or carbonate are introduced, say from a calcium reactor, or the addition of Kalk, the equilibrium and the pH are shifted in one way or the other.

In the case of a calcium reactor, it's not that the carbonic acid level is necessarily any higher, its just that the carbonate concentration is lower because it is used up neutralizing the carbonic acid, which results in more bicarb. When the carbonate becomes completely depleted there is nothing left to neutralize the CO2 and the pH starts to fall.

In addition to all this, as if it needed to be more complicated. The natural trend for pH in an aquarium's pH is downwards. In addition to naturally produced CO2 (from plants, corals, alga, and bacteria) there are also organic acids such as acetic acid (vienegar) that are produced as a by-product of bacterial activity. These push the pH down, as well as the alkalinity. This is the major reason that alkalinity will fall faster then calcium. The only major drain on calcium is from calcification (growth by corals, snails, coralline algae, etc.) When trying to maintain the balance in your water, you have to meet both the demand from buffering as well as calcification. Corals also use more alkalinity then they do calcium in calcification as well. Its not a simple 1:1 reaction.

[matt]

As far as I know, carbonates and bicarbonates reach an equilibrium in water depending on ph, so I'm not really sure what Gary's talking about with regards to "calcium reactors lower ph by producing a "low carbonate to bicarbonate ratio". Calcium reactors introduce calcium ions and carbonate ions into your tank and I don't think bicarbonate has anything to do with it. Typically introducing bicarbonate does not raise ph while carbonate does; since calcium reactors only introduce carbonate, this could not depress ph. The reason calcium reactors sometimes depress ph is simple; you're dosing effluent that has a ph of 6.5 or so into your system.

In this case it sounds like you just have your reactor turned up too much. Don't stop the KW or your ph might really plummet. (If your ph is currently really high, which I seriously doubt, stop the KW just until it falls into a normal range) Instead, just turn off the reactor until your levels are where you want them. Then start it up again, slowly. Get your effluent ph at around 6.5-6.8 (ARM runs best a little on the high side, the new schuran media is best a little low) and drip SLOWLY into your tank, maybe a drop every second or two, no faster. You'll have to keep the CO2 rate down to hold a steady effluent ph at that slow rate. Okay, when that's done, just keep monitoring your tank Ca and Alk and if it drops, bump up both the CO2 and effluent flow, keeping the effluent ph the same. It takes some time to get the right flow vs CO2 vs ph to get a reactor dialed in, but it should be pretty rock solid once you do.

KW is pretty good at maintaining Ca levels but not as good with Alk levels. It's pretty common to use KW and still need to dose a buffer; I use my KW reactor to replace all evaporated water and I still need to add a few teaspoons of baking soda a week, but only occasional dose of turbo calcium.

Unless you're seeing signs of imminent disaster in your livestock, I'd just let the Alk fall on it's own. Watch your ph!

[safeuerwehr]

thanks gary and matt...and like i meantioned before i had my effluent cranked up all the way so now ive addjusted an its only like 1 drop per second....will keep you posted on changed

[matt]

Do you have a ph probe? If not, now's the time to get one, so you can accurately monitor your effluent ph; it's really the only way to dial in the reactor. If you want, post your tank ph and your effluent ph and we can take it from there.

[GaryP]

Matt,

You are absolutely correct in saying that pH is determined by the ratio and equilibrium of carbonate and bicarbonate. As you said, you are introducing effluent at a pH of 6.5 from a reactor. But the question is what happens to that effluent after it mixes in the tank? Why doesn't the whole tank go to pH 6.5 eventually? I'm looking at it from a more systematic approach then simply what is happening in the reactor itself. What is the complete reaction of a calcium reactor? Isn't it something like this?

CO2 + H20 -----> H2CO3 ; CaCO3 + H2CO3 ---> Ca + 2 HCO3

That's bicarbonate (HCO3), not carbonate (CO3) being produced. In addition, if there is residual CO2 coming from the reactor (what gives it the 6.5 pH in the first place), this takes place:

H2CO3 + CO3 ----> 2 HCO3

In both cases, there is an increase in bicarbonate, and in the case of residual CO2 there is a depletion of CO3. The equilibrium is moved towards HCO3 and a lower pH. That's how a buffer works, by moving hydrogen or hydroxide ions back and forth between the complementary buffer components.

What you are proposing is that this happens.

CaCO3 + H2CO3 -----> Ca + 2 CO3

What happens to the 2 hydrogen ions? In a buffered system, I suggest this is what happens.

2 H + 2 CO3 ----> 2HCO3

If that occurs, we end up in the same place, with a net of one calcium and 2 bicarbonate and the loss of 2 carbonate. In either case the equilibrium slides towards more bicarb, less carb, and a decrease in pH.

To me the more important issue is that alkalinity is being produced at a ratio of 2:1 to calcium. As I mentioned earlier, there are other demands on alkalinity besides just calcification, such as neutralization of organic acids and biogenic CO2 and this absorbs some, but not all, of the excess bicarb. However, as I am sure you will agree, a calcium reactor's production rate should be set based on the alkalinity demands of the system. Any shortfall in calcium supplementation needs to come from other sources, such as Kalk or calcium choride. Kalk has the ability to both help regulate pH and also supplement calcium. This added factor though, is what I feel makes operating a calcium reactor a bit too complicated for most hobbyists. Its not just a matter of opening the CO2 valve and fiddling with the rate until it does everything the tank needs. For example, Kalk also produces alkalinity by neutralizing CO2. So, on top of the excess alkalinity that the reactor is producing you have to figure in that from the Kalk. The higher the pH, the lower the solubility of CaCO3, so you can end up with not only an out of balance system, but a precipitation problem as well.

Admittedly, many reefers have had a lot of success with reactors. I'm not saying that there isn't a lot that have. They do a very good job when they are set up and dialed in. That is until something in the system changes and they have to be adjusted again. If you are doing a good job of testing and monitoring, that is not a problem. Don't you also see a change in performance as the media bed get older as well? Isn't there more channeling of the CO2, resulting in lower media contact and performance? I'm sure there is some sort of break even point where performance is balanced with cost and you need to change media before it is completely spent.

[matt]

Gary, I didn't say that ph was determined by the bicarbonate/carbonate ratio, but that the ratio is ph dependent. (It might be, I just didn't say that) Adding carbonate at typical tank ph will raise the ph, because it pulls H+ ions from the tank, but adding bicarbonate does not really lower the ph (theoretically a little, but at typical tank ph it has a very small effect) because few of the bicarbonate ions disassociate into carbonate ions at tank ph. So, I suppose you're right that reactors release bicarbonate rather than carbonate, or I guess more accurately a mixture that's almost entirely bicarbonate, but I'm pretty sure the ionic balance adjusts to tank ph more or less immediately with little effect on the ph. I'm pretty certain the reason reactors sometimes lower the ph is because too much carbonic acid gets into the tank too quickly for the tank's buffers to deal with.

Regarding changing calcium demands and reactors, sure, as corals grow, etc, the calcium demand increases and the reactors need to be adjusted to meet it. This is true with all types of supplementation. And, as the media dissolves, the flow within the reactor changes and so forth. But, it should be pretty minimal; that's why I used pan world pressure rated pumps for my reactors; they keep the flow pretty steady. It's also why the new schuran media is popular; it's not granular, it's large chunks of calcium carbonate and supposedly flow issues are much better with it.

You are right that many people use reactors without carefully adjusting them; in fact, most of the people I've visited using my reactors have them out of adjustment. One common problem is controlling the CO2 flow with the lousy regulators sold for aquariums. That's where the $40 dwyer flowmeter comes in; you get a rock solid CO2 flow and a much more stable reactor ph. The other thing is to have a valve controlling water flow into and out of the reactor; you put a little more flow in than you want coming out, and dial it down just a little with a cheap plastic needlevalve on the way out, and it almost always stays pretty stable. But, you absolutely need a good ph probe to run a reactor IMO, because you need to accurately monitor effluent ph. This can be a fancy permanent probe installed in the reactor, which I never used as it presents another leak point, or just a simple hand held probe; once a week you collect a littel effluent and test it. Simple.

I'm thinking of building a small reactor with the schuran media for my corner tank. I figured out with my current demand, I would need to add somewhere around 100ml/week of B-ionic (maximum) to supplement my KW. So, it would take a LONG time to equal the cost of a reactor, even if I build it...($50 for tube, $80 pump, $150 for CO2 set up, etc...) but now my corals are all pretty small and growing fast. Besides, I've never run a calcium reactor and KW reactor at the same time and I'm kind of curious to see how it goes.

[hobogato]

matt - i used the kald reactor without the calcium reactor for a couple of weeks, and notice a difference in growth over just dosing B-ionic. once i added the calc reactor also, things really started to improve. over the last month or so, i have been tweeking both reactors and now my tank is more stable than it ever has been. my corals are growing faster and the color even looks better (maybe i am imagining things here) my tank pH runs 8.2 day and night, my calc. hovers around 500, and my alk stays right at 10 Dkh. i am dosing magnesium to make sure i dont run into precipitation issues. i think if you add a small calcium reactor to your tank - you will be glad you did.

[Richard]

and the color even looks better (maybe i am imagining things here)


I doubt that you are imagining it. There more to coloration than just lighting. A kalk reactor with a calcium reactor is the ideal setup but just a calcium reactor is still much better than relying on additives like b-ionic IMHO.

[JimD]

I happen to like my kalk reactor and B-Ionic thank you very much. I only use B-Ionic twice a week at 30ml doses each part and my Ca hovers around 440 and Alk at 9.

[safeuerwehr]

matt i do have a milwakee ph meter....tank is at 8.2 and effluent is at 6.9....

[urban79]

dam my eyes are hurt from reading this thread..

[hobogato]

Alfred - is your reactor a single tube or dual tube reactor?

[matt]

I happen to like my kalk reactor and B-Ionic thank you very much. I only use B-Ionic twice a week at 30ml doses each part and my Ca hovers around 440 and Alk at 9.

Jim Norris used this same set up with great results. I think ideally you would have a second dosing pump to automatically drip the B-ionic; the innovative aquatics pumps can dose equal quantity of 2 part additives. That way your Ca and Alk would never budge. For smaller tanks it's really tough to beat this in terms of cost effectiveness. I think in JimN's 240 he was really going through the B-ionic, and I bet Ace would also be spending alot on the stuff. You can make a 2 part additive easily with dowflake and baking soda; not much different than what I'm doing now which is to add a small amount of baking soda and turbo calcium.

You're essentially doing the same thing with a calcium reactor, just in a different way. I'm curious about the new schuran media. I had some doubts about ARM when I was using it; one thing is that toxic metals are more soluble in a low ph solution, so if there are any impurities in the media, they're going in the tank due to the low reactor ph. There have been some studies about media impurities, but to my knowledge nobody has analized the schuran media for this. It's plenty expensive, that's for sure!

One of the many great things about KW is the fact that you have no ph worries, unless of course you accidentally overdose.

[Richard]

I happen to like my kalk reactor and B-Ionic thank you very much. I only use B-Ionic twice a week at 30ml doses each part and my Ca hovers around 440 and Alk at 9.

I should have said just a calcium reactor or just a kalk reactor is better than relying SOLEY on additives like B-IONIC.

It's just a matter of stability I think. Most (not all) people do not follow a real good dosing regime when relying only on additives. So their level bounce up and down like a yoyo.

[matt]

Oh yeah, Alfred, if your tank ph is 8.2, definitely don't stop the KW drip. KW tanks usually run higher than 8.2, which makes me think there's some carbonic acid in your tank from the reactor effluent shot you gave the tank. How's your Alk, coming down? You might want to stop the calcium reactor altogether until your tank Ca and Alk are near where you want them.

If you're using ARM, I think 6.9 is a little high. 6.7 seemed to be the sweet spot for that stuff in terms of maximum effluent dkh without turning the media to mush. One other thing, you definitely need calibration fluid to calibrate your ph probe; you can get it at Analytical scientific supply. I also have a milwaukee probe, and it needs constant calibration. Mine is the cheap one that only calibrates at 7.0. Hopefully yours uses 7.0 and 10.0 (I think?) and has a .01 resolution. I never should have bought the one I did.

[JimD]

Norris was adding 30ml of each part daily along with two of my kalk reactors and he was getting pretty fair results, I know he wasnt using a Ca reactor, at least not for very long. . Just to clarify, Im not actually using B-Ionic, Im using the home brew with baking soda and dow flake. It just proves that theres more than one way to achieve success.

[matt]

Ah, the home brew...I'd like to try that myself. Do you have your own recipe or are you using Randy Holmes-Farley's? Can you post it?

[GaryP]

Gary, I didn't say that ph was determined by the bicarbonate/carbonate ratio, but that the ratio is ph dependent. (It might be, I just didn't say that) Adding carbonate at typical tank ph will raise the ph, because it pulls H+ ions from the tank, but adding bicarbonate does not really lower the ph (theoretically a little, but at typical tank ph it has a very small effect) because few of the bicarbonate ions disassociate into carbonate ions at tank ph.

Whether pH comes from pH, or buffering comes from pH is sort of a chicken or egg proposition. In some ways they are the same thing. pH is determined by buffer equilibrium, and changes in buffer equilibrium are the result of acid or base inputs.

[JimD]

matt and everyone else, here ya go....
www.advancedaquarist.com/issues/april2004/chem.htm

[hobogato]

Ah, the home brew...

im having one of those right now ^_^ oh, you meant the two part additive - my bad.

[safeuerwehr]

matt... i have the upto 10 and i calibrated it before setting it up....alk today was at 19 dkh so it slowly going down....and hobo its the square reactor i pmed you about...and to all hobos wife make a mean home brew.....

[matt]

Definitely do not use your calcium reactor until the dkh falls to a normal range, I just mention it because you said you slowed it to a drip.

[safeuerwehr]

yeah its off now.....thanks matt

[matt]

Just curious, what's your tank dkh, ph, and calcium now that it's been a few days?

[safeuerwehr]

matt....just ran some tests and heres what i came up with

ph 8.4 with electronic monitor....has been holding here for a few days now...
cal 340 seems low but thats been my normal reading prior to adding the reactor
dkh 12 which has really come down from the 25 after reactor overload

now when do i start up the reactor again and how often do i drip the kalk.....LMK thanks for checking up on this....

alfred

and on a side note...my tank is looking much healthier since i put the new skimmer online....the cyano is almost gone and the hair algae is receeding and floating off the rocks.... :D

[GaryP]

For what its worth, I would try to get your calcium back up and in balance with the alk. before starting the reactor. Some calcium chloride should do the trick. I certainly wouldn't worry about a pH of 8.4.

[TexasTodd]

When you start your reactor you want your CA and ALK EXACTLY where you want to keep them. You don't want to run them up or down with the reactor. This is the number one mistake with CA reactors.

Start with the reactor putting out slightly lower amounts than you think is needed. Measure 2x a day. If the tank specs have fallen, use B-Ionic's two parts to bring it back to optimum. Then adjust your reactor up slightly. Keep doing this every day until the reactor keeps it even. If you try to do it all just using the reactor you'll keep swinging up and down for a LONG time.

Do you have a single or dual reactor? Shoot for a EFFLUENT ph of about 6.5 out of a single, or, 6.8 or so on a dual.

Todd

[safeuerwehr]

todd.....I'm running a dual chamber square reactor....I had the effluent down to 6.8-6.9 with a drip rate of about 60 drops per min..with the co2 bubble rat of around 30...if u read my original post I had the effluent cranked up all the way so it overdosed the tank...but I did more reading and now I have and idea as to where to start..this system still has a few bug that I need to work out but I'm well on my way to getting an understanding on how a reactor works....thanks for any and all the info and advice.

alfred

[matt]

Gary's right about adding some calcium chloride (wait, did I just say Gary was right about something?) to bump up the Ca to 400 or thereabout. This might knock your ph and alk down a little, no biggie. Here's a link to a site that can calculate how much you need to use, and some other good info.
http://home.comcast.net/%7Ejdieck1/chem_calc3.html

Once that's done, start up the reactor, very slow effluent drip, if you're using ARM go for 6.7-6.8 effluent ph. You can also check the effluent alkalinity with a salifert kit using the low resolution (1 drop of the green reagent) it should be around 25, anything over that is great. If it's under 20, lower the ph to 6.6 and try again. Todd's also right about using the reactor to maintain levels rather than raise them. Otherwise you'll have a real see-saw.

I would keep dripping KW 24/7. Unless your ph is too high (Calfo says 8.6 in the afternoon is fine) there's no reason to stop it. If you have a high calcium demand, KW on it's own won't keep up. Another thing, it was probably the KW that saved your tank during your calcium reactor bath...if you hadn't been dripping KW and you put enough reactor effluent into your tank to send your alk as high as it got, you probably would have had a very low ph.

[GaryP]

Gary's right about adding some calcium chloride (wait, did I just say Gary was right about something?) to bump up the Ca to 400 or thereabout.
I was probably overdue. It happens every once in a while.