I have some sheets but it'll be Feb before I get to it really.
Too many other projects going that are more important time wise.

Regards,
Tom Barr

Here is another idea! It is a CO2 "thermometer", a device that is an analogue of a digital thermometer. I haven't, of course, tried to make one of these yet, but only because I am busy with other things, and because I haven't yet figured out how to weld or glue a membrane to a piece of plastic without damaging the membrane. Who wants to make a prototype of this?

Yes, this is the same thing I suggested to Greg Morin much like their ammonia alert thingy.

Having a ref color scale next to it is ideal though, too many folks have trouble determining the color differences.

Regards,
Tom Barr

That would be great if they chose to produce something like this. But, without the technology to weld or glue the membrane to the plastic, achieving a perfect seal around each ref. KH well, it isn't a DIY project.

I'd be happy to take a shot at it as soon as it slows down a bit here. 3 Blizzards in 3 weeks and another on the way WTH ??? Shoveling snow is not nearly as much fun as I remember it to be. Should'a held out in PA for a few more weeks...

I need as much feedback as possible on diffuser materials just as soon as folks try them out, as I really don't care to own an assortment of it. Happy Holidays ! Prof M

Which material are you working with Tom ? Grtz, Prof M

Why not slap a webcam with a reference white/gray/exposure-point on it and you have a "Continous DIY Colorimeter Drop Checker (tm)".

Hi Tom,


Earlier in this thread you said to dry baking soda like this.

>>>Cooked/baked bakign soda: 400F for 45 min.
Use about 2x what you think you need.<<<

I was hoping you could look at this link and tell me what you think.

General Chemistry Online: FAQ: Introduction to inorganic chemistry: What happens when sodium bicarbonate is heated?

This site says that at 392 degree's F that the sodium bicarbonate actually changes to sodium carbonate.

So is this the reason for the 400 degree oven temp. so that it will be converted to sodium carbonate?

""Sodium bicarbonate is even less stable with respect to heating. Solid NaHCO3 begins to lose carbon dioxide and water around 100°C, with complete conversion to sodium carbonate by 200°C:
2 NaHCO3(s) CO2(g) + H2O(g) + Na2CO3(s) ""

Thanks,
Bill

Do you think it's time dependent?
I do.

I think it does raise a good point.

So, rather than such high heat, maybe 100C or less, the air dryers work well to remove H20.

And guess what's used in the air dryers? CaCl2, which is readily available.
My advice is based off of what several reef folks have gone through at RC.

I know there's issues with such methods, but for the hobbyists, I try and balance the trade offs with some things that they can do.

You could place the Bakign soda in a sealed jar with a nice batch of CaCl2 and baking in thin layers in seperate trays. This will help remove the water from the baking soda, without decompsing it.

CaCl2 is commonly used in air dryers for Chemistry.
Might take awhile though.It's tough to rectify either situation to a very accurate degree for the hobbyists.

I think maybe lower heat would work fairly well if you spread the baking soda out in a thin layer and just heat to about 80-90C.



Regards,
Tom Barr

Tom,

Any thoughts on how baking at the higher temperature would affect the accuracy of the drop checker when trying to indicate a CO2 level of 30ppm.

I made a 40dKH ref solution up having heated to 200c and mixed 90ml of this with 10ml of DI water to produce a 4dKH reference solution. I did a quick check with a Nutrafin KH testkit and it certainly given the inaccurcies of such test kits, the results did seem to be around 4dKH.

When I get time I'll probably try mixing up a new batch of 40dKH solution, having baked the bicarb of soda at a lower temp (80c - 90c) and make up a 4dKH solution from this. Then I can compare 2 drop checkers in the same tank to see if there is an obvious difference in the colour reaction.

Al