Bill Stock wrote:

I bought some Cabomba a couple of weeks ago and it seemed to do OK at first,
but has been losing needles lately. I know the water was too alkaline for
it, but my CO2 regulator was delayed. I have the CO2 running now and the PH
is down to 7.5ish for now. I plan to go to 7, once I get a PH controller.
The soil is not the greatest either, plain aquarium gravel (clown puke) with
quite a bit of natural sediment. Everything else is OK, light, Iron, N-P-K,
etc.

So do you think the PH is the main issue? It does seem to look a little
better tonight, but that's somewhat subjective.

My water is liquid rock and I presume this is the reason why I can't
grow this plant. My pH will naturally rise beyond 8.2. But I now inject
CO2 for the plants and get the pH down to 7.25. The Cabomba still dies.
The lighting is 3 watts per gallon. Two things I can do is soften the
water or increase the lighting. Neither of which I'm prepared to do, so
I avoid the plant. Let me know if you find a solution!

Nikki