Here's a shot of the Bacopa breaking the surface of the Duckweed
patch in the jug experiment and a shot of the original clump of these stems. I took one, cut it so that it was just tall enough to be at the surface of the jug two days ago, and it is doing well.
I wonder if I can get this to flower this way... if so I will have an excuse to keep the jug as it will look a little more aesthetically pleasing to my wife.
I added some more sand to allow better rooting of stems as they get taller.
KH is run down to between 6 and 7... say 6.5. I thought the bottom might have been 4, and it may be, but I had to add some water due to my testing.
I did a pH test a few days ago. It's been riding 8.4 so I took a glass of water out after sundown (min CO2 concentration) and let it stand for a few hours while intermittently bubbling it to see if I could inject some CO2 into a depleted water. The second test did show a slight drop in pH, not enough to say 0.2 but enough to see a definite difference in the purple colour towards 8.2. I have to assume that is from a slight increase in CO2 concentration. This using only air. How much was from me bubbling and how much was from just surface contact, I don't know. With the Duckweed
mat in the jug, surface transfer would be minimal anyway.
I forgot to test the pH in the morning to see where it sits after the plants do their respiration bit and to compare it to my little bubbling test.
I may buy a small air pump and stone and bubble the jug to see where the pH ends up.
Anyone have any suggestions for a really quiet really small air pump and a fine fine stone?
I know this doesn't get the KH addition test anywhere as adding CO2 into this environment using just air would only work in a severely depleted tank. But I am curious and I have some work to do before testing anything else anyway.
I could start with fresh water, bubble in the air and compare the KH reduction from the get go.... another time, but I might expect the KH to be depleted slower, not at all or have a higher "bottom end" if the air can diffuse CO2 into the tank at a similar rate as the plants will use it.
I am looking toward setting up a plant only tank with the bare minimum of external support (filters, pumps lighting) so everything that I do here is pertinent. I've got this west facing wide window ledge in my office that would be cool to have a tank in and not have to worry about fish.