[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Bishop CO2/pH controller

Regarding the Bishop pH controller at

>Has anyone else built this thing?
	I built a couple of versions of it, but couldn't get it to work well
enough to be useful.  It's a clever idea, but the probe is S-L-O-W to
respond to changes in the tank CO2 level -- so slow as to be useless, in
my experience.  If I were going to try it again (and I might -- it's a
clever idea), I'd try to speed it up by putting the probe IN the tank
("diving bell" style), and by increasing the surface area to volume
ratio, which I think it critical: if you have a 5 ml sample and 1 square
cm of surface area, you can wait all day for the sample color to change.
> I am unsure of the VCC
	It all runs on the regulated 5 volts.
> He also didn't mention how much reagent to add
	The usual 3 drops/5 mls seems like a good amount.
	My advice, for what it's worth, would be to go with the Hurley pH
control system (www.thekrib.com/Plants/CO2/hurley-co2.html) with a $33
"Silver" probe from Pet Warehouse.
	If y'all techie types would care to continue this discussion off-list,
please drop me a line.
Sherman   lovell at wa_freei.net