Reactors and Additives [Archive] - Canreef Aquatics Bulletin Board

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pocilipora

01-27-2002, 06:03 PM

Does any one here using a Calcium reactor, also use additives? Such as moly,stront,iodine,etc.

DJ88

01-28-2002, 12:22 PM

Chris,

I think most people(I know from what I have seen) use only the reactor. I don't dose anything else myself. I use ARM in my reactor.

reefburnaby

01-28-2002, 03:27 PM

Hi,

I really only use a buffer to bring up my alk...once in a while.

- Victor.

SuperFudge

01-29-2002, 10:43 PM

Hi Chris,
Nothin for this guy either!....but if it makes ya feel any better,my girlfiend likes to sprinkle that Damn carpet deoderizer,then stir it up in the air with the vacume every once in a while,so i can give you good list of crap that gets in there ! images/smiles/icon_biggrin.gif

Victor,you have a reactor....Co2`s much cheaper than buffers... images/smiles/icon_wink.gif .

Marc.

reefburnaby

01-30-2002, 12:44 AM

Hi,

Yeah, I use buffers to keep my tank at a relatively high alk. I have a bit of green/brown algae in the tank. They produce CO2 that uses alk. Once the algae disappears, then it should be fine.

Although it is possible to dial my reactor to keep the alk high, this could cause my calcium levels to reach unsafe levels (>450ppm). So...I dial the reactor for constant calcium levels and add buffers to keep the alk above 15.

- Victor.

[ 29 January 2002: Message edited by: reefburnaby ]

[ 29 January 2002: Message edited by: reefburnaby ]

SuperFudge

01-30-2002, 10:26 AM

Victor,

I doubt the small amount of algea in your system could even put a dent in the alk.
A low Calcium is probably(believe it or not)is one of the parameters i least concern myself with.
Alk being at the top of the scale.
Having said that i cannot explain the chemistry involved but i could say that a low alk and a high calcium is probably much more of a concern than the reverse,IME.
When tested(albiet never images/smiles/icon_wink.gif ),my calcium reads only in the neighborhood of 375-400+/-,yet my Sps thrive.....i think maintaining high alkalinity allows sps to metabolize(?)all elements more efficiently.
In the past,when i used buffers it was totally the reverse....with kalk/buffers i could maintain calcium but not a decent alk,this resulted in a MUCH(like probably 3-4X) slower growth rate aswell as a loss of good color.

At this point if anything i would even increase my alk higher and loose abit more calcium.

Of course its JMVHO though,Marc.

[ 30 January 2002: Message edited by: Fudge ]

reefburnaby

01-30-2002, 11:49 AM

Hi,

I guess I should point out that my Ca reactor adds most of my alk in to my tank. I only add a dose of buffer every month.

Did you know that we are using the same philosophy (high alk and medium Ca). So, I dial in my reactor to have constant Ca levels (380 ish) and my alk is never allow to go down past 10 dKh. The reason why I try to keep Ca levels constant is because I don't want it to go out of control and hit 500 ppm (which means calcium snow). I think that is much worse than having my alk dip to 10 dKh or as high as 12 dKh. Also, high Ca ppm causes faster buildup of calcium deposits on equipment and such.

- Victor.

[ 30 January 2002: Message edited by: reefburnaby ]

SuperFudge

01-30-2002, 12:12 PM

<blockquote>quote:<hr>Originally posted by reefburnaby:

Did you know that we are using the same philosophy (high alk and medium Ca). So, I dial in my reactor to have constant Ca levels (380 ish) <hr></blockquote>

Oh,i mustve misunderstood your prior statement....."Although it is possible to dial my reactor to keep the alk high, this could cause my calcium levels to reach unsafe levels (>450ppm)".

images/smiles/icon_confused.gif

Marc.

[ 30 January 2002: Message edited by: Fudge ]

DJ88

01-30-2002, 02:17 PM

You have me confused Victor..

<blockquote>quoteI have a bit of green/brown algae in the tank. They produce CO2 that uses alk.

I am fighting bryopsis in a small tank and have to say I have a LOT more algae than in your 90. I am seeing no difficulties keeping my alk at 12dKh all the time. And if I desired it takes nothing for me to push those numbers up.

From what I have read your Ca reactor isn't doing it's job. If you are having to add buffers to keep the Alk levels up you need to increase the CO2 injected into your Ca reactor. A Ca reactor is there to maintain your levels. If you are adding buffers it isn't doing it's job. IMVHO.

I know you know the chemistry behind all of this but, I can keep my Alk at the levels you want in my tank with no use of buffers, and my tank is heavily stocked in Ca and Alk loving corals in comparison to yours. Just an assessment I have made from seeing your system and it's occupants. I keep my tank at 12dKh as they love it and grow like weeds but can crank it up a few notches if I want. I have done it but prefer it at 12.

Maybe I am lost in space tho. But when you need to add buffers something isn't working properly, IMO.

images/smiles/icon_confused.gif images/smiles/icon_confused.gif images/smiles/icon_confused.gif

Marc,

What do you keep your Alk at? Curious to find some differences in our systems besides lighting. Want to see if I can get an idea as to what causes the color differences between the purple digitata in my tank and yours.

[ 30 January 2002: Message edited by: DJ88 ]

SuperFudge

01-30-2002, 03:25 PM

Hey Darren,

Last time i checked it was about 210 PPM as carbonate hardness,so if i remember right thats about 11+? dkh........overall total alkalinity will be a slightly higher tho...

I would bet the majority of the colour difference results from a higher alkalinity in your tank..... harder to achieve with an increased demand in my system.....soon i will have about 1/3rd the sps and i will seperate the frag vat....giving me a good boost.

Marc.

[ 30 January 2002: Message edited by: Fudge ]

DJ88

01-30-2002, 03:53 PM

<blockquote>quote:<hr> FWIW, changes in CO2 only will have no impact on alkalinity (but of course huge ones on pH). So if you bubble CO2 into seawater, the alkalinity will remain unchanged (but the pH will drop). Likewise, if you somehow suck off all the CO2, the alkalinity will remain unchanged (but the pH will rise) Changes in alkalinity through the day would, IMO, reflect process involved in alkalinity addition (limewater etc.) and alkalinity consumption (e.g., calcification, parts of the nitrogen cycle, etc.).
<hr></blockquote>

That is a quote from Reef Central discussing alkalinity levels and CO2.

You may want to look at your CA reactor. I don't think it is doing what you think it is. FWIW

Acro

01-30-2002, 05:05 PM

Acro

01-30-2002, 05:16 PM

Victor, Have you ever had your calcium over 450ppm? and if so what was you alk at at this time?

DJ88

01-30-2002, 05:25 PM

<blockquote>quoteIf there is a lot of CO2, then alk is consumed and Ca stays the same.

Did you see what I quoted above? I'll post it again.

<blockquote>quote:<hr>FWIW, changes in CO2 only will have no impact on alkalinity (but of course huge ones on pH). So if you bubble CO2 into seawater, the alkalinity will remain unchanged (but the pH will drop). Likewise, if you somehow suck off all the CO2, the alkalinity will remain unchanged (but the pH will rise) Changes in alkalinity through the day would, IMO, reflect process involved in alkalinity addition (limewater etc.) and alkalinity consumption (e.g., calcification, parts of the nitrogen cycle, etc.).
<hr></blockquote>

CO2 has no effect on Alk. This is from a chemist who does research with CO2 in solutions. Where are you reading that CO2 consumes Alk??? This is where I am really lost. It doesn't make any sense to me. Even without a chemistry degree I can see that CO2 has no effect on Alk. It does on pH as I see this daily with my pH monitor. I have measured my alk at many different times in the day and it never varies by any huge amount. pH does that is for sure. And I now know this is due to CO2 in the system.

<blockquote>quoteIs Bryosis calcium based ? If it is, then it will consume Ca and alk too

No it isn't.

<blockquote>quoteAlso, you use an kalk reactor (and I don't). The kalk reactor will consume a lot of the acidity of the CO2. Hence, alk is maintain (never increased).

Stopped using it over a month ago till I build a new one. *anyone want a used nielsen reactor?* My Alk is still at 12. Measured it three times today to make sure. And CO2 isn't acidic. Once it interacts with the water it lowers the pH of the water.

<blockquote>quoteAlso, my tank has three times the volume as yours but maybe 50% more water surface area. So, it will take longer for my tank to blow off CO2 (hence more alk consumption...if the CO2 does not get blown off).

With the larger waters surface to me you would get rid of excess CO2 faster than I would. The reason people have the effluent of a Ca reactor drip into a container is to increase the surface are of the effluent to release any excess CO2 in the effluent. As for Alk consumption I think you are a bit off in what happens in a system with regards to Alk CO2 Ph and Ca. I know you know the formulas and such. But I still say if you are having to add buffer to your system your Ca reactor is not dialed in correctly. To me it is as simple as that.

CO2 does not use up alk. that is what confuses me the most. I have posted two separate quotes by chemists to this fact.

<blockquote>quoteI haven't add Calcium to my system for a very long time. So I am either not consuming calcium (at all) or my reactor is working. So far, my SPS are growing and my coraline is spreading. So...it must be the reactor is working

Your Ca requirements in your 90 are quite minimal. It doesn't suprise me your reactor can keep up. But if the Alk is dropping(which is more important to keep track of in a system) your Ca reactor is not working. It doesn't get much more simple than that.

<blockquote>quote:<hr>If there is a lot of CO2, then alk is consumed and Ca stays the same. So, there are many things that can happen. If things aren't perfect, either Ca or alk will be consumed faster than the other. In my case, alk is falling a little bit faster (1 dKH over a month). Does that make sense ?
<hr></blockquote>

nope. if your alk is dropping your Ca reactor isn't working. CO2 doesn't consume alk.

reefburnaby

01-30-2002, 05:30 PM

Hi,

Wait a minute, if CO2 drops pH and it isn't an acid...then what is it ?

----

Wait....I am working out equations....it is a bad day for me today....

- Victor.

[ 30 January 2002: Message edited by: reefburnaby ]

DJ88

01-30-2002, 05:33 PM

In solution. you stated CO2 is an acid. It isn't. In solution CO2 brings the pH of the solution down.

<blockquote>quoteThe kalk reactor will consume a lot of the acidity of the CO2

Am I misreading this?

DJ88

01-30-2002, 05:36 PM

<blockquote>quoteI haven't add Calcium to my system for a very long time. So I am either not consuming calcium (at all) or my reactor is working. So far, my SPS are growing and my coraline is spreading. So...it must be the reactor is working

I think you are consuming very little Ca in all honesty. If any at all. And if that is the case(which I suspect) your Ca reactor is doing nothing other than acting as a water circulation system. The main indicator for this is the fact that you have to add Buffer to your tank to boost Alk back to normal levels. That is a warning sign from your tank that something is not right. You may want to heed it.

DJ88

01-30-2002, 05:53 PM

<blockquote>quoteWait....I am working out equations....it is a bad day for me today....

Sorry if you are having a bad day Victor.. images/smiles/icon_sad.gif those bite.. Usually all modays are like that for me.. images/smiles/icon_biggrin.gif

But that aside,

Equations mean squat to me. I work in electronics and laymans terms in reef-keeping I am not a chemist. When I go to school to learn chemistry I will look at them. I understand in easy to decipher words and sentences. I see equations and such in a post and I skim over them. You may as well write in greek for all that it is worth. images/smiles/icon_biggrin.gif

I know you know the equations. We all do. I can go get them all off boards or other online sources if I want. Personally I don't. Those formulae are useless to me. They are pretty but.

What I think it comes down to is that your Ca reactor is not doing what you think it is. Post the equations in the chemistry forum on RC and also post what you are having to do with your tank to keep Alk up along with your tanks parameters. Talk to a chemist and I am sure you will see what I and others are trying to convey to you. Something is fishy in your reactor.

First you need to have a lower effluent flow rate to get the Ca and buffering out of that piece of equipment. Too high a flow and too low of a CO2 rate and you get water passing through with no dissolving of media and thus no Ca or buffering happening in your system from your reactor. The best indicator of this is that you have to boost your Alk.

The first thing you shoudl think when you are having to boost your Alk is that my reactor is not keeping up. If it is not keeping up I need to do something such as;

<ul type="square"> Increase bubble rate of CO2, keep flow rate the same, to drop pH of effluent to increase buffering Slow down efflunet flow rate. Keep CO2 the same. This will increase buffering due to the decreased pH of the effluent. all of the above
[/list:u:fd90559103]

Your system is telling you something. Adding buffer is making up for what your reactor is not doing. If your tanks Alk is dropping due to consumption why not use the Ca reactor as it was meant to be used? It is an adjustable device there to do a job so you don't have to do it.

Acro

01-30-2002, 06:01 PM

You can only go down a dead end road so many times

reefburnaby

01-30-2002, 06:05 PM

Hi,

This is why kalk is dripped (and not dumped). There has to be enough CO2 to combine with the OH-.

Kalk is composed of Ca and OH-. So

kalk = Ca++ + 2 (OH2-)

CO2 when mixed in water becomes :

CO2 + H2O <=> H2CO3 <=> H+ + HCO3-

where H2CO3 is a carbonic acid and HCO3- is a bicarbonate. Okay...so, when the two mix...you get :

Ca++ + 2(OH-) + 2H+ + 2HCO3- <=> H2O + 2HCO3- + Ca-. So, the alk stays the same...but no more CO2 and one more Ca++.

AH....i see the light. Okay...CO2 doesn't get absorbed. Okay...you are right...it is a weak acid. However, acids from fishes and decaying matter (say...did you notice my decaying macro algae ?) will absorb some of the alk.

I will check my reactor (again). I am sure it is okay. Either that...or I am confusing myself between the time I didn't have the reactor on my 90 and after. I did have problems with my reactor intially (kept plugging up at the valves and the flow was fine one day ... and nothing two days later). I fixed that...so maybe that's why I add some buffer. Okay...I'll check it tonight and see what it is.

Thanks.

- Victor.

reefburnaby

01-30-2002, 06:59 PM

Hi,

I know some like to avoid the math and get to the practical stuff. I like to mix it a bit...mix some practical and get some theory down too.

I mentor a lot of engineers so I have to provide "proof" that I am not making things up. Which...usually means equations.....

- Victor.

Canadian

01-30-2002, 07:23 PM

Just for the record:

"You do not really understand something unless you can explain it to your grandmother."

-Albert Einstein

And my grandmother isn't a chemist.

DJ88

01-30-2002, 07:33 PM

Victor,

It is not that I want to avoid the math. As a technician I had to work with formulas all the time. Especially now.

It is that in this hobby the GAFF(Give A F*#k Factor) for chemical formulas and such is very low. How many people honestly go that indepth with this hobby. With regards to chemical intereactions. If I can explain it in such a way that everyone including myself can understand it then I am doing those out there reading a big favor. When people see those formulas they roll thier eyes and scroll down probably 90% of the time. I do. If I really wanted I can sit down adn research it to undersatnd all of it. But why? If you like to at home, great. Kudos for you. We aren't chemists, and most here aren't engineers. I'll gurantee you that there are people on this board who won't participate in these discussions as they are intimidated or can't understand the first thing about chemical interactions down to the molecular level. I last took Chemistry in high school. 15 years ago. I am sure there are others who didn't even take chem as they had something else they were more interested in.

With that said, I still think your reactor is not running right. It isn't a matter of plumbing, you need to slow the effluent rate to decrease the pH so that you are actually using your reactor for something more than a water circulation device.

I'll let this be now. Maybe you will take the advice and experience being offered and follow it. Maybe you won't. Your choice. But I know that if you don't you will still be adding buiffer to your tank for a looong loong time. And once you try putting more of a Ca demand on your system to the point that it starts falling too you will need to add Ca as well. Then what is the point of even running a reactor if you are dosing as well??

Hmmmm???

Acro

01-30-2002, 07:35 PM

Andrew,
I would have to go on the show Crossing Over in hopes to explain it to my grandmother. j/k ] images/smiles/icon_wink.gif
Victor,in all seriuosness you don't need to get to complicated about things. Bottom line... Ask yourself why you have a reactor in the first place.

[ 30 January 2002: Message edited by: Jamie Cross ]

Aquattro

01-30-2002, 07:46 PM

Just in case this helps anyone, here is an excerpt from Sanjay Joshi's paper.

"There are basically two adjustments that can be made to an operational reactor — the effluent flow rate and the amount of CO2 added. In the steady state, the trick is to balance the output of the reactor with the daily consumption of alkalinity in the tank.

Increasing the CO2, while maintaining the effluent flow rate, results in a decrease in the pH of the reactor and hence an increase in the solubility of the CaCO3 media, and hence a higher alkalinity in the effluent. This increase in alkalinity of the effluent will be seen up to a pH range of 6.3 to 6.5 and any further decrease of the pH in the reactor will start resulting in decreasing alkalinity. Increasing the effluent flow rate, while maintaining a fixed amount of CO2 will result in an increase in pH in the reactor and hence a reduction in the alkalinity of the effluent. By adjusting both the effluent flow rate and the CO2 injection rate, a fixed pH can also be maintained in the effluent. Some advocate maintaining a fixed pH of around 6.5 in the reactor.

I find it much easier to adjust the reactor based on the alkalinity output rather than the pH measurement. I would recommend first setting up an effluent flow rate so it flows in a continuous steady drip, and then making adjustments to the CO2 flow rate to increase or decrease the alkalinity of the output. For most tanks this approach will work fine, but if you have a heavily loaded small-polyped scleractinian (SPS) coral tank, then it may require you to increase both the effluent flow rate and the CO2 injection rate. A certain amount of fine-tuning is required to adjust the reactor for your particular system.

Having a good estimate of the daily consumption of the alkalinity in the tank and understanding some of the “reactor math” can help in eliminating some of the trial and error in fine-tuning the reactor. Let us assume that the reef system contains T liters of water, and the effluent flow rate is L liters per hour and the estimated daily alkalinity consumption is c milliequivalents per liter (mEq/L) per day. Now, measure the alkalinity in the tank and the alkalinity of the effluent. The difference between the two values will give you the increase in alkalinity due to the reactor — call this d (mEq/L) — as follows:

alk/day added due to the reactor = (d x L x 24)/T Equation 1

So, now we need to adjust the reactor so that the daily increase due to the reactor is approximately c mEq/L. This will give us the setting at which the reactor will replenish the alkalinity that is consumed daily.

Looking at the Equation 1, we can see that there are three ways this can be achieved:
Only adjusting d — the increase in effluent alkalinity
Only adjusting L — effluent flow rate
Adjusting both d and L.

The effluent alkalinity can be increased (or decreased) by correspondingly increasing (or decreasing) the amount of CO2 and keeping the effluent flow rate constant. This provides one convenient way of tuning the reactor output to the aquarium needs. When increasing the amount of CO2 added care must be taken to keep the pH level above approximately 6.3. I personally use this approach to adjust my reactor. If I find that I have to injected too much CO2 so as to cause the pH in the reactor to drop below 6.3, I am better off also increasing the effluent flow rate through the reactor.

Increasing the flow rate will result in a decrease in effluent alkalinity if the CO2 flow rate is not simultaneously increased. Several manufacturers recommend adjusting both the flow rate and the amount of CO2 simultaneously to maintain a constant pH (about 6.5) in the reactor and hence a constant alkalinity output in the effluent. I prefer having to just adjust one parameter — the CO2 flow rate. Both approaches will satisfy the needs of the user, but the key is to balance the daily consumption to the daily addition of alkalinity."

StirCrazy

01-30-2002, 09:45 PM

http://jabot2000.homestead.com/files/emoticons/stupid.gif

<blockquote>quote:<hr>Originally posted by reefburnaby:
Hi,

kalk = Ca++ + 2 (OH2-)

CO2 when mixed in water becomes :

CO2 + H2O <=> H2CO3 <=> H+ + HCO3-

where H2CO3 is a carbonic acid and HCO3- is a bicarbonate. Okay...so, when the two mix...you get :

Ca++ + 2(OH-) + 2H+ + 2HCO3- <=> H2O + 2HCO3- + Ca-. So, the alk stays the same...but no more CO2 and one more Ca++.

- Victor.<hr></blockquote>

I do like chemical equasions http://jabot2000.homestead.com/files/emoticons/cop.gifbut don'f forget Victor that the equasions you are using as a example are assuming all you have is "PURE water, PURE kalk, and C02". and all in exact ratios. we all know there are hundreds of other chemicals in the tank that will cause all new and exciting reactions to happen. so in all practicality it is ok to use the equasions to get a idea of what is going on but unless you want to do a studdy one every element in the tank and there ratios and then bring up the effect that motion of the elements and temp cause.. well you see I alreays would have packed it in images/smiles/icon_smile.gif I love Chem but not that much http://jabot2000.homestead.com/files/emoticons/jawdrop.gif

Steve

Aquattro

01-30-2002, 09:58 PM

Steve, I saw that....

Silverfish

01-30-2002, 10:57 PM

Well, alls I can say is .... tomorrow I pick up my 15lb co2 tank and I hope to soon say good-bye to that pesky dosing!!

ldzielak

01-30-2002, 11:08 PM

These reaction formulae show the basics, but these are balanced equations, with no indicators as to what shifts the balance, temp? pH we all know does, this is how the reactor works right? When you change the CO2 flow and leave the rest, you change the balance. ARM says to set pH to 7.5 but if you read on the boards some say 6.5 the answer is find the balance for your systems demand and match the pH or output of the reactor.

Victor, how did you solve your valve pluging problem? I have to adjust my effluent needle valve every day or two.

DJ88

01-30-2002, 11:13 PM

Lee,

I am running ARM in my reactor and have been keeping the pH at 6.9-7.0. I measured my alk today in my tank and it is still at 12 and my Ca is at 490. so you can run it higher than regular media. If you run it down near 6.5 it turns into soup. just so ya know. images/smiles/icon_smile.gif

Aquattro

01-31-2002, 12:07 AM

Darren, that's good to know. I'll fire mine up tomorrow. If I hurry, I'll beat Grayfish, er, I mean Silverfish images/smiles/icon_biggrin.gif

reefburnaby

01-31-2002, 12:56 AM

Big Opps....

I looked in my log book tonight and I notice that I haven't add buffer since late November. Okay... I take that statement back that I add buffer. I used to add a lot of buffer in my old 20....

According to my log, the only thing I add is Selcon -- in the form of Selcon soaked food.

Sorry for the confustion. I can't think straight today...I had the CTO (Chief Technical Officer), two directors and three managers breathing down my neck today. Not a fun day.

Yah...I'll try to tone down on the equations next time...

Thanks.

- Victor.

reefburnaby

01-31-2002, 04:48 AM

Darren,

I should clarify this some more. I think the difference between your tank and my tank is that you probably have two to three times the calcium consumption as mine (if not more). Since the reactor produces both calcium and alk (at a balance rate), then you will be adding more alk and calcium in to the system than me. Let's suppose that our algae is the same and it burns off the same amount of alk. What may seem to be a big drop in alk for me, you might see it as a small change. This is because your system is consuming a lot more alk than mine and you are adding back a lot more alk than mine.

Also, my tank has three times the volume as yours but maybe 50% more water surface area. So, it will take longer for my tank to blow off CO2 (hence more alk consumption...if the CO2 does not get blown off).

Is Bryosis calcium based ? If it is, then it will consume Ca and alk too (hence the large calcium + alk demand). It probably isn't but...

Also, you use an kalk reactor (and I don't). The kalk reactor will consume a lot of the acidity of the CO2. Hence, alk is maintain (never increased).

I haven't add Calcium to my system for a very long time. So I am either not consuming calcium (at all) or my reactor is working. So far, my SPS are growing and my coraline is spreading. So...it must be the reactor is working images/smiles/icon_smile.gif

The alkilinity, as I understand it, is design to prevent the pH from dropping too much when an Acid (like CO2...with is carbonic acid) is added. To prevent the pH from dropping too much, the alk ions actually absorbed the acid to create a salt (neither acidic nor basic). Now, it is possible to have high alk and low pH...it just means not all of the alk ions are bumping in to the acid particles. If given't enough time, the alk ion bonds with the acid. This is the primary function of a buffer and it's job is top absorb acids. Be it carbonic acid, acids from nitrogen cycle...eventually it will depress.

I am not sure if I got my biology correct, but Corals do exactly the reverse of what a reactor does. It takes two bicarbonates, a carbonate and a calcium ion...then it uses those to form its skeleton. Ideal, if the alk is consumed by other means, then the reactor should be able to match exactly the draw from the coral. Suppose the Ca ppm was very high...then precipitation occurs more often (CaCO3, thus the Ca drops and alk stays the same. If there is a lot of CO2, then alk is consumed and Ca stays the same. So, there are many things that can happen. If things aren't perfect, either Ca or alk will be consumed faster than the other. In my case, alk is falling a little bit faster (1 dKH over a month). Does that make sense ?

- Victor.

[ 30 January 2002: Message edited by: reefburnaby ]