lovely, thanks Richard

I think I understand how the dKH reference works. What I cannot picture, or visualize, is what do I do with it? What do I put it in? How or where does it get placed in the tank? Is it connected to anything or is it a "passive" setup or device (ie. not connected to air or water flow)?

Can someone post a picture? I would like to experiment with this on my first CO2 tank, a 20 long, which is all I have room for at the moment. How much room do the drop checkers take up?

-Jason

You put some 4dKH water in it, then a few drops of blue bromide reagent (PH checking solution).. then you just stick it on the glass inside the tank somewhere that you can see easily, and that gets a moderate water flow.

It works by CO2 crossing the air gap between the tank water, and the water in the checker.. this takes upto a couple of hours to happen, so results arent instant. Because there is no physical connection to the water in the tank, you eliminate getting false readings because of PH altering substances in the tank.

By using 4dKH water, the checker should turn from blue/green, to light green/yellowy when the tank acheives a CO2 ppm of about 30.

But what is the "it" you are referring to? What am I sticking into the aquarium that holds the reference solution? Can it be something DIY? Is it a specially shaped glassware? That's what I'm getting stuck on. What does a drop checker look like?

ahh i thought you had one and were asking how to use it.

drop checker

this is the posh ADA one, there are lots of other types on ebay though

Ah! Ok. I have seen that before, but out of context. It makes much better senese to me now. Thank you.

The link in the first posting brings me to a page with explanation, but how and where do I order the KH solution from Bill?

EDIT: Have it setup with Bill allready through email /EDIT

Evert

Anyone in Australia looking for a lab grade KH solution, i will have a 40°KH solution available in the next week, i can dilute it down to 4° or get the lab to do it. Please PM me if you want any.