Baking Soda, Washing Soda and Baked Baking Soda

[jfinch]

I made a batch of baked baking soda when I ran out of washing soda. When I used it I noticed that it did not cloud the water ( Mg(OH)2 ) as much as the washing soda I had been using. Curious, I decided to titrate my baked baking soda. Pure sodium bicarbonate should have 11.9 meq/g while sodium carbonate should have 18.9 meq/g. My baked baking soda only has 14.4 meq/g. I then think I aught to check the baking soda and washing soda too. My box of Arm and Hammer baking soda has 11.7 meg/g. My new box of Arm and Hammer super washing soda only has 16.3 meq/g. At this point I'm wondering if my lab skills are lacking as the baking soda number is right on but the washing soda one is low. So I get a bottle of reagent grade sodium carbonate from the stockroom and titrate it. This stuff titrated to 18.7 meq/g. I guess my titration skills are ok

A couple things surprised me. The baked baking soda wasn't all converted to sodium carbonate. This isn't a big deal, I kinda like it this way. There's not as much rise in pH when using. But the more surprising thing was the washing soda. It titrated to only 16.3 meq/g. What else is in there? I doubt it's bicarbonate as sodium carbonate is used to make sodium bicarbonate (not vise versa). It might be CaCO3 which wouldn't really be a problem either. But it could be... well who knows? Anyone here hazard a guess?

Anyway, I now feel more comfortable using the baked baking soda over the washing soda since I know I'm starting out with a product that's all good.

[Boomer]

Washing soda is nominally Na2CO3.10H2O, Sodium carbonate Decahydrate but it loses water to the atmosphere (effloresces), developing a white powdery surface to the crystals. The material is Na2CO3.xH2O where x will be less than 10 by an amount depending on the age of the crystals and indeed varying from crystal to crystal. Pure Soda Ash is Na2CO3. This may have something to do with it all.

A couple things surprised me. The baked baking soda wasn't all converted to sodium carbonate.

It normally isn't. You usually end up with a mix somewhere between Baking Soda and Washing Soda. It depends on how much CO2 is blown off.

[Mimbler1]

Boomer, does baking longer or at a higher temp convert more bicarbonate to carbonate?
thanks Mike

[jfinch]

Washing soda is nominally Na2CO3.10H2O

Thanks, that just might explain it. And makes me feel better

[Randy Holmes-Farley]

jfinch:

How long and at what temperature did you heat it?

FWIW, I forgot to take that water of hydration into account in my article on solving alkalinity problems where I calculated how much alkallinity you get from washing soda (where I equated washiong soda and sodium carbonate).

[Boomer]

You mean YOU made a mistake. Hang on a sec...........got to get the little black book out and give you a check mark

OOP'S, just noticed another one Washiong Soda

We know how many times I have done that

I remember long ago, even though I'm old, you teasing me about Soda Ash as an old word

Sodium Carbonate = Soda Ash = Na2CO3

Sodium Carbonate Decahydrate = Washing Soda = Na2CO3.10H2O

[jfinch]

Randy, I baked it in a small dish at 300F for two hours. Since it wasn't spread out as much as it would have been on a cookie sheet, I stirred it about 4 times during the drying. I think I would have had better conversion if I would have spread it out more.

If my washing soda has 16.3 meq/g and is hydrated, that calculates to a MW of 123 which is only about 1 additional water. I obviously wasn't aware that sodium carbonate normally exists in a hydrated form, but I don't think Arm and Hammer washing soda has much water.

[Randy Holmes-Farley]

One of the reasons that I didn't recommend washing soda in my article on the DIY two part additives (in addition to the lack of purity controls) is that I could not find any Arm and Hammer documents that described how much water is typically in it.

[jfinch]

I can't edit my last post, but it should say "16.3 meq/g and if hydrated..." not is hydrated... I don't know if it is or not. It could very well be other impurities. But I do feel better thinking it's H2O

[Boomer]

Randy

I could not find any Arm and Hammer documents that described how much water is typically in it.

I spent more than an hr lookin and could find nothing either. I suppose one would have to call them for an answer. Maybe I'll do that for you tomorrow. I'm on vacation for 5 weeks I also need you to PM me your home address, as I' going to send you all that fancy HACH stuff I have just sitting around. FREE to you and other assorted test kits and some probes. Many will need new reagents

[biodegraded]

I several days ago looked into replacing the reagents for my Hach alkalinity test kit. The set was 5 cents less than buying a whole new kit. I found that any of the titration only kits were the same (calcium and total hardness, for example.) The only time one saved a few bucks buying just the reagents is for those kits with fancy readers like color wheels.

[Boomer]

My kits aren't the norm, they are digital titrators. The titrator alone is $ 120. Not to meniton all the glass ware, graduated cylinders, beakers, etc = + $ 175, without any reagents. My kit was almost $ 500 when I got done custom building it .My phosphate kit is a color disc, that measures all forms of phosphate, $ 140 .


FF-3 & PO-24

www.hach.com

[Randy Holmes-Farley]

My Hach silica and phosphate kits use the wheels, so the reagents are less expensive. I agree that with the calcium/magnesiium and alkalinity kits, there isn't much there except reagents.

[biodegraded]

Nice kit, Boomer. I hadn't thought you'd be giving away a digital titrator kit to someone. That's very generous. In that case, yeah, the reagent costs are a smaller fraction of all the stuff. I do like my Hach kits, even the lower grade ones.

[jfinch]

I use the Hach reagents using a Hach Spectrophotometer DR/2000 machine at work to test some parameters of my tank water. Boomer, you mentioned in another thread that this machine might not be ok for seawater. Is that true? If so can you elaborate (because the Hach water handbook say's those methods are good for freshwater, seawater and wastewater)?

[Boomer]

Yes, that is true. I called them a few years ago and asked the question is it accepted for seawater and when it got right down to it the answer was no. I should have thought of you yesterday when I was on the phone for an hour with HACH for Scott, aka Travellar Mod of the Anemone forum. He was lookin at the new HACH HSA -1000. I thought it would work as it works off of electro-chem but the Cl -and sulfate in NSW are waayyyyyyyyy to high and the Mg and Ca are on the border. I will call them for you tomorrow and Arm & Hammer also

[Boomer]

Called Arm & Hammer and waiting to find the x value in Na2C03. xH20, is that x the std 10 or something else or is there a range they allow, say 6-10

Called HACH on the DR-2000 or on other similar Colorimeter/Spectrophotometers

You must go to the manual for a particular ion, note its interference levels of ion x, y or z etc.. to see if it is higher in NSW. Example, the meter can be calibrated to seawater, but if the ion interference, for say PO4, is no greater than 5,000 mg / l Cl- , then it will not work, as NSW is 19,000 mg / l. You can not use this unit for Alk, this has been brought up before, must be a titration method. For nitrate, yes but you will have to make up your own stds ( just what I said before). The manual will list all of the interference ions and their levels, so you will need to go here to see the ion levels in seawater, to see if the concentration in seawater is to high for those ions interfering to measure X ion and if it is with range of the unit.

http://users.rcn.com/patwilde/ocpertbl.html

So, in short, it will work for some ions in seawater, it will give wrong readings for some if you don't make up stds and some ions you will not be able to measure at all. You will also need to calibrate the wave length for seawater, also in the manual

[jfinch]

Thanks Boomer. I feel like I should be paying you or something
I'll read through their water handbook. ortho phosphate, silica and copper are the only tests I use ('cause we do those tests daily for our cooling water and condensate). Unless you think I should be checking for chlorine residual, sulfite or triazole?

[Boomer]

I would not use that book, they have a full on line PDF for that DR-2000. I see no wave length correction for seawater in the book. Also take special note, there are three ways to measure PO4, i.e., Amino Acid Method, Molybdovanadate Method and Ascorbic Acid Method. This is a real issue here for seawater. The Amino Method will do PO4 Ok but not the Moly Method, Mg interferes at greater that 1,000 mg / l and NSW is around 1,300 mg / l. The Ascorbic Acid method also seems Ok.

Silica looks OK

Cooper looks OK

Others ?/

Well, I would say Sulfate at 900 mg / l or so but the unit only goes to 70 mg / l and Ca interferes at 500 mg / l

DO if the NO2 is not above 10 mg / l, which it should be nowhere near

Ca and Mg but that is a no go, only goes to 4 mg / l

There are others to play with, look at the list it is a mile long but but I didn't look at their interference factors

[olemos]

I'm still new at this
what's the diferance of making the dow flakes with baking soda and doesing kalkwasser ?

[Randy Holmes-Farley]

The difference? You mean why pick one over the other? There are a variety of differences that may make one or the other more suitable in a given situation. What kind of tank do you have (or have planned)?

I compare the pros and cons of different supplementation methods here:

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm

[jfinch]

Boomer, again!

I'm using the phosver 3 powder pillows, I think that's the ascorbic acid method so I should be ok there. I seldom check copper, actually I've only checked it once along with my tap water and RO/DI.

Our ammonia test method includes a distillation step and I haven't had the nerve to drop my salt water in the still , but I've thought about getting the Nitrate reagents...

[olemos]

Originally posted by Randy Holmes-Farley
The difference? You mean why pick one over the other? There are a variety of differences that may make one or the other more suitable in a given situation. What kind of tank do you have (or have planned)?

I compare the pros and cons of different supplementation methods here:

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm

I have 350 GL 5 month old ready to introduce corals
yes I would say why pick one over the other (dosing kalk or dow flakes) from what I understand thy both do the same thing
again I'm new at this just trying to understand what works better
and why

[Randy Holmes-Farley]

Depending on what corals you want to keep, you might want to use either or both. If you expect a big demand for calcium and alkalinity, perhaps a CaCO3/CO2 reactor instead, or in addition to, one of those methods.

Anyway, the article compares them and should help you decide. The only issue is that the DIY two part is not discussed, just commercial 2 part systems that are more expensive.

[Boomer]

Jon, yes that is the one, as long as the silcate is not over 10 mg / l, so that should not be an issue at all

Nitrate reagents

Will not work until **YOU** make up stds with a known concentration of NO3 at x salinity (HACH has no such std for NSW). You must spike a seawater solution to a know level, i.e. 5 mg / l and then check the meter to see what the error correction will be. This is in the owners manual so they tell me

For nitrate, yes but you will have to make up your own stds ( just what I said before).

I'll send you the bill