If your potting media has high cation exchange rate like clay, it would bind the
fertilizer. The fertilizer has little chance of dissolving into the water
column.

2pods wrote:

Sorry to hijack the thread, but while we're on the subject of lillies, is it
possible to harm pond plants by using lily tabs ?

The consensus seemed to be OK, but after one big tab the plants seem to look
worse.
A bit floppy and "dry" looking ?

Peter