Ive heard that there are a couple plants out there that are very good indicator plants for levels of fertilizers in the water column. If you can list what plants have been good for you in the past please do so =). Here is my experience with Heteranthera Zosterifolia.
Lack of N - leaves turn pale and transparent.
Lack of P - tips will start turning black.
Lack of K - plant will stunt.
Lack of micros or (Fe) - plant will become transparent
Lack of N - leaves turn pale and transparent.
Lack of P - tips will start turning black.
Lack of K - plant will stunt.
Lack of micros or (Fe) - plant will become transparent