[Sinhalaya]

I had numerous plants in my aquarium die and some are dying. After considering many causes, my LFS person thought my tank might be too acidic. This was because I use ADA soil and have high tech CO2. But when I tested my water the PH was >8.4 and the KH was >300. Is this what's killing my plants? Shouldn't the Co2 and the drift wood lower the PH?
(all other parameters are within normal ranges)

 

[Sinhalaya]

Water temperature is 78 degrees with two 200 heaters at both ends of the tank. Lighting is a 48" Finnex Ray 2 and a 48" Finnex Fugeray Planted Plus. Other parameters are
Nitrate <20
Nitrite 0
Hardness (GH) 0
Chlorine 0

Our water is softened so it is not hard at all and there's never any chlorine after it's filtered. I still add prime just to be safe. The only things I did not get from a aquarium store are the rocks, I believe they are moon stones there are about 8 (small and medium size). The tank has been established for a couple of months and the KH and PH are always high even with water changes.

 

[Sinhalaya]

The only things that have survived up to date are the anubias nana (dwarf). Every other plant has died, I've tried a wide range of plants and all have died. The anubias is also dying but its from BBA than anything else. The BBA is new and did not contribute the death of other plants.

 

[Sinhalaya]

I live in texas, Travis county. The water here is VERY hard so most houses use softners. I think all the water coming in through the main lines runs through the softner. In case even the garden tap also runs through the softner is there any other way to solve this?

 

[Sinhalaya]

how about using something like "API pH Down"? maybe that will help the plants

 

[Sinhalaya]

This makes a lot sense since I never had any problems with my 10 gallon at my old place. The plants in my 10 gallon have not died but are not thriving either, in fact they're slowly declining. Since I just did a huge water change yesterday I'll wait until Monday to do another water change. Would that be too soon? Hopefully running the water from the garden hose will not be too cold for the tank. Thanks all for your help.