The ebay purchased nano glass co2 diffusers I have (all three of them from 2 different vendors) are essentially inadequate as best as I can tell. They do not do a very good job of diffusing the co2, the bubbles are fairly large and they give off a bit of a whistling noise that you can hear across the room.
I swapped today to Fluval's diffusion disc (same one that comes with their 88 sized pressurized co2). Its not as attractive as the glass but it does a 100% better job at diffusing the gas and it doesn't whistle while doing it
I received a call from one of my LFS's ... they have in 3 Blyxa Japoinica plants for me. I can now replace the Limnophila! I trimmed it again and moved tops down to bottoms, but a lot of the remaining bottoms are definatly getting worse for wear. Sadly I can't get out there until Saturday to pick them up, but at least I know they are waiting for me