The Amazing Shrinking BTA

[sp1187]

I've got 4 BTA's, all of the same type/color.
Three are growing nicely. The fourth (the last one added) has shrunk from 4" diameter to the size of a quarter since purchased in March.
NO3(50/60) & PO4(1.2) are elevated, but I have to wonder why that would affect one adversely and the other three thrive.

 

[maroun.c]

All I can think off would be alleopathy if they were not closes but thats a very controversial topic. Try to run some heavy carbon for awhile and change frequently to see if that makes any difference.