Baking soda & Washing soda ? Brad?

Hi Mike and thanks again for the help.

I knew that I should have taken chemistry instead of rock science in high school all those years ago. ;)

I was also thinking that the pH would reach a ceiling one day and am hopeful that we are both correct.

The tank is really loaded with hard corals, many SPS and LPS, and a lot of live rock. The thing that concerned me was that my coral growth rate has slowed, the coraline is in a holding pattern and I was starting to see a small amount of problem algae pop up. After seeing these changes take place I tested the Alk and realized that it was very low and in the range of 1.5-2.0 so I started to use the buffer but when the pH climbed I would stop and never get above 2.5meg for more than a day.

One interesting thing is since I started using Brad's buffer the Alk tonight is at 3.0-3.2meg which I am very happy to see. I have never had an increase in Alk like this when using the commercial buffers like I have seen using bs/ws combination.

As far as the Calcium goes it did drop from 370 down to about 250-300 based on my calcium test since last week. I had added some Tropic Marin Bio-Calcium last night and will continue to use that and the combination of Brad's buffer to bring things back to par. Once I get things back to normal, Alk about 3.5-4.0 and Cal around 400, I will start to use kalk again for my top off and hopefully at that point I will be able to use less buffer and still keep levels that I and my corals will be happy with.

On a good note, the expansion from my LPS today is better than it has been in quite some time and overall I am very suprised with the quick response from only two days of adding a buffer of this type. I can even see the polyps expanding on my green/yellow soft coral that I have not seen in sometime.

Thanks again for all the help.

Doug
 
Hey guys, me again :) I must say I've had 3 semesters of college chem thus far and I'm still a lil' overwhelmed by all of this, but I have q's for ya and hopefully you can help (I have all the chem professors and other biology profs confused to this point, so watch out! hehe).

Ok, here goes. First I want to know how is it possible to affect the alkalinity w/out altering pH? I have had several customers bring in to me water samples that were a lil' low in pH, ie. 6.0 or less (freshwater here fellas). They have used several commercial phosphate and carbonate buffers as well as baking soda to bring the pH up. Well they were having huge shifts in alk, going from a mid range of 180ppm to about 300ppm. But alas the pH never moved. What's up w/dat? I've been told it could be an accumulation of CO2, so I should aerate the samples before testing, did it, notta. (I should point out that I've used several different tests on each sample and have pretty much ruled out defective tests).

Now if it it were a problem w/excessive CO2, wouldn't carbonic acid be formed? And wouldn't that resultant acid cause a drop in the alk? Please help me here, I'm soooo frustrated and confused over this. I have had more people experience this and nothing seems to help them. Do u have any ideas?
 
Hi Fishbait,

Well, I'm no chemist and I'm certainly not that up on FW, but I'll tell you what I think. Maybe a chemical type can tell you chemical reasons why.

My experience with SW is that ph is established based on the component parts in the water. The carbonates are one of those components, continually interacting with each other, the tank water, and the atmosphere. At NSW levels of all those elements, and in an open air atmosphere that's not polluted, you have the typical 7-10 dkh alkalinity and ph of around 8.3. Put another way, the hydroxide ions and hydrogen ions in this soup establish an equilibrium at that ph.

Below around 2 dkh, ph will start to fall and can fall quickly, and above 20 dkh ph will begin to rise. At around these points, the actual ionic makeup of the water changes. Obviously at 4 dkh ph can fluctuate much more easily with changes to the water, while at 15 dkh ph will be much more durable. I'm guessing that these alkalinity ranges more or less correspond with ph ranges of 8.0 - 8.5, assuming a consistent atmosphere. Put another way, at 2 dkh you still have the ion balancing point at the same place, just fewer hydroxide/hydrogen ions on each side of the equation. At 15 dkh, you have the same equilibrium point, but many more ions on each side of the "tug of war".

When you add bicarbonate, or carbonate, you simply increase the ions on one side of the equation temporarily (resulting in a ph change). But ultimately, due to interaction with the atmospheric co2, the more major ions transform to the other side of the equation restoring the original balance and ph.

Now, here's where I'm guessing much more. As gases involved in the environment change, the ionic balancing act gets "skewed". More co2 = more constant skewing of ph to the lower side (see Mutagen's post above about co2 exchange/ph) with the hydrogen ions being more dominant, while less co2 = less constant skewing of ph to the low side with hydroxide ions being more dominant. Photosynthesis is also a tremendous contributor to the gases involved as the process uses o2 and releases co2.

During all these processes, carbonates are being used which is why the natural trend in a closed system is for a loss of alkalinity. I'm guessing that the loss is somewhat more rapid with a co2 rich atmosphere, than it would be otherwise.

I have no idea if this answered your question or even helped. I'm also interested in hearing further responses. And I apologize in advanced to the more chemically fluent for my tortured use of chemical terms.
 
Man, can I use u guys for stand-ins next semester? :D All I can say is my head is hurting from all of this thinking. Mike u have a ton of info there and to be honest I don't follow alot of it. Maybe one of u guys could give the chemical equation of what may be happening? I tend to understand things like this better if I see it. I really had no idea that atmospheric gases had THAT much of an affect on our systems. I think I learn more here than I do at school!!
 
Fishbait,

This thread is getting long and I'm no longer sure what all your questions are, so I'll try to translate what Mike said into chemical equations.

CO2(g) <-----> CO2(aq) _________H
H2O + CO2(aq) <----> H2CO3 _____Keq1
H2CO3 <-----> H+ + HCO3- _______Keq2
HCO3- <-----> H+ CO3-- _________Keq3
H2O <-----> H+ OH- _____________Keq4

Each of these equilibrium equations has its own equilibrium constant. The solubility of CO2 will depend on the partial pressure of CO2 in the surrounding atmosphere and it has its Henry's law constant. At equilibrium, all the equation's equilibrium constants are satisfied. Anything which perturbs the system will temporarily create a state of disequilibrium. For a given alkalinity and CO2 partial pressure there will be only one equilibrium pH. However, our systems are in a constant state of change with respect to both alkalinity and dissolved CO2. We also perturb the system when replenishing alkalinity and calcium. The manner in which the system is perturbed depends on the method we choose to replace the alkalinity.

The equilibrium constants for these equations in salt water systems are now fairly well established and it is possible to solve for all the constituent concentrations at equilibrium. Basically it is 5 equations and 6 unknowns plus a charge neutrality requirement so the system is properly specified for a unique solution.

This system provides a great deal of confusion. It is a simultaneous equilibrium system where CO2 effects pH but not alkalinity. Furthermore, we use the terms alaklinity and buffer interchangeably though they don't have the same chemical meaning, but that's OK becuase the alkalinity and buffer capacity are provided by basically the same constituents!

If you continue to pursue chemistry courses, you will eventually study multi-component, multi-phase equilibrium and all will be revealed!

Good luck, Mutagen
 
Hopefully this thread is still being read!

Hopefully this thread is still being read!

Went to Walmart and United (the largest supermarket chain in West Texas). Couldn't find Washing Soda. Had the clerks look it up on the computer (since they had never heard of it) and it wasn't there.

Where do you folks buy it at?

If I can't find it, I'll give Mutagen's baking the baking soda thing a go. How precise is the 450 deg for 30 minutes thing?

Sound like a fun and an easy DIYer and I'll save a buck or two. That's 20 minutes of long distance you know!!:)
 
Hi Aaron,

My wife picked up my Arm and Hammer washing soda at Jewel. I am not sure if they have stores all over the Country but it is a large food store chain in the Chicagoland area.

Did you look in the detergent section? My wife said it was near the dish soaps and household cleaning solutions.

HTH

Doug
 
Hi Aaron,

I found it in the local grocery store, Save Mart. When I mentioned to my wife, she knew about it instantly (I'd never heard of the stuff). I would try some other local grocery chains, but you probably already know that :)
 
Hi Aaron,

I had another thought. Like I mentioned earlier in the thread, you can also find sodium carbonate at pool/spa supply places, or hardware stores where they sell ph products for pools. Just check the label because various chemicals are used for ph up products. But some definately use sodium carbonate.

Another possibility is to send me an email with your address and I'll buy you a coupla boxes of washing soda and send it to you. This amount will only last you .... like about 5 yrs :). I'd gladly do that if you want.
 
Thanks Mike!!

Let me give it "the old college try" today. I've got three more stores mapped out. One of them was the LFS. If I couldn't find it at the first two, I was going to throw in the towel and buy buffer at the LFS ;)

I'll email you if I'm unsucessful.

Thanks again. Yet another reason why this board is so good. It is full of good people...
 
Conflicting info above

Conflicting info above

Is it 1 part baking soda to 6 parts washing soda or 6 baking soda to 1 washing soda
 
Doug said:
I had added some Tropic Marin Bio-Calcium last night and will continue to use that and the combination of Brad's buffer to bring things back to par. Doug
Click to expand...

Doug,
I just wanted to point out that Tropic Marin Bio-Calcium increases alk. If you want to just increase ca, use calcium chloride instead. I know it doesn't state this on the container (I use it also), but according to my test kits and RFH it is a balanced additive.

Chris
 
chriss said:
Doug,
I just wanted to point out that Tropic Marin Bio-Calcium increases alk. If you want to just increase ca, use calcium chloride instead. I know it doesn't state this on the container (I use it also), but according to my test kits and RFH it is a balanced additive.

Chris
Click to expand...

Thanks Chris.

I didn't know that about the Bio-Calcium and appreciate the info.

I ended up installing a Calcium reactor on my 90g tank since the calcium load in my tank kept increasing with the addition of more SPS corals.

Thanks again.
 
Probably a stupid question but when you say 6 parts to 1 part is that a certain amount or can it be 6 cups to 1 cup or 6 oz to 1 oz?

Just verifying. Thanks
 
Use whatever measuring units you wish, just keep the ratio 6:1.

So 6 cups to 1 cup or 6 grams to 1 gram all works.

This needs some more confusion :D
I found that I was having chronic high pH issues because I dose kalk which has much higher pH than even washing soda, so I had to eliminate the washing soda from my buffer formula.

The pH of baking soda seems to want to be about 8.0 which chills out the kalk. (7.0 is neutral, so it still fizzes vinegar at pH 8.0. Our tanks are somewhat basic) Now my pH hangs around the 8.1-8.3 range very nicely. It still goes up a little during the day, but I have a ton of algae making a ton of oxygen, so it makes sense.
 
Yes thanks Frick-n-Frags! I mixed it up and dosed according to the teaspoon per 25 gallons on the website for the first time 2 1/2 hours ago. I did a test and it did bring my alk up 1.2 dkh. I want to dose again to bring it up some more, but how long should I wait or does it matter? PH is stable at 8.33 currently.

ALK was at 7.8 and now is at 9. I would like to get it to 10-11 but dont know how long I should wait between dosing or if it even matters.

Thanks
John
 
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