How long do you bake your baking soda for?
 

I was told 30 minutes on 350F but online I've read 4 hours at 400F. What do you all bake it for?

I've always gone by the guidelines in this article:
http://www.reefkeeping.com/issues/2006-02/rhf/

I'm pretty sure it was written by Randy Holmes-Farley, and it suggests baking at 300 for an hour, though he states that over-heating in terms of either temperature or time doesn't do any harm, but it doesn't do any good either.

+1, at least back when I used to make my own soda ash by baking baking soda. I started just buying bulk soda ash because the one thing I found about this method is that the baked baking soda would have a tendency to clump really badly if added too quickly to water. It's like it's been dessicated to the molecular level and the molecules are desperate to bond to anything and then won't let go.

Not sure if there's anything to be done to work around that short of adding very small amounts at a time into a bucket with a powerhead or pump mixing as you go.

I bake a whole cookie sheet sized about 1/2" thick for an hour. Then mix it into near hot water. Dissolves very easily. Never had a clumping problem. I mix it in a big plastic bowl with a plastic spoon with slots. Each batch i mixed for 2L. But only took less than 10 mins each to mix.

No clumping at all? Wow, I wonder what I was doing differently. It sounds exactly the same as what I would do: I would take the 2 cups needed for 1 gallon and bake it on a cookie tray about 1cm/0.5" thick. I grew so frustrated with the clumping I clean gave up doing it that way. Soda ash is easy enough to source nowadays (BRS/Eli/Concept/etc/eieio) that I don't really plan to go back to doing it that way but a part of me always wondered why it would be such a problem for me and not for others..

I found the few times that I did it that it would practically solidify on the baking sheet, and the larger chunks didn't dissolve nearly as easily. Is that what you mean by clumping? It was like you would almost need to put it through a blender to get it back in to a fine powder that dissolved quickly. I was never sure if soda ash just has a lower solubility, or if it was the fact that I was trying to dissolve larger pieces (I'm sure I could have looked it up, but meh), but it was annoying enough that I stopped doing it and just stuck with regular old baking soda for my alk

Thanks everyone, I baked a whole box on a cookie sheet for a hour on 400F. I didn't get any clumping this morning.

At 350 for 3 hours.

That's exactly what would happen to me, except it would happen after I added it to water. I tried adding it to warm water, I even tried adding it to water heated up to a boil to see if it would be less of a problem, and it was not as bad, but it still happened. It would solidify into a rock hard consistency and the only way to break it up would be to use a blender. Eventually my wife banned me from using her blender :lol:

I'm totally happy with the soda ash from Eli so have no plans to change back to baking soda, but I am just still totally stumped that some people seem to have no problems whereas for me it was basically ridiculous.. There must be something to attribute this to!!

so a whole box of baking soda will last how long