MB...

Have you tried taking the plant out of the pot to get a look at its roots structure? Just lift her out and take a pic of the rooting system. the colors of the roots can tell a lot as can the tendens coming off the main root stems can as well.

3 gallons is small...yes its doable as i have done, but i allowed for extra oxygen with the lava rock.....perhaps yours are oxygens starved.

You can take fishing rod and poke long holes all the way thru the soil to improve the O2 flow.

But i would love to see the root system.

Come now, show us amandas pretty little panties