Reactors and Additives - Page 2

DJ88 · #11 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.).
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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 · #12 01-30-2002, 05:05 PM

Acro · #13 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 · #14 01-30-2002, 05:25 PM

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If 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.).
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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.

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Is Bryosis calcium based ? If it is, then it will consume Ca and alk too

No it isn't.

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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).

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.

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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).

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.

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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

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

reefburnaby · #15 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 · #16 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.

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The kalk reactor will consume a lot of the acidity of the CO2

Am I misreading this?

DJ88 · #17 01-30-2002, 05:36 PM

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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

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 · #18 01-30-2002, 05:53 PM

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

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

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. [img]images/smiles/icon_biggrin.gif[/img]

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 · #19 01-30-2002, 06:01 PM

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

reefburnaby · #20 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.