About to start fertilizing mine and so I was doing some research today. Came across this page. Can't speak to the accuracy of the info, but the last paragraph might be of some help. Talks about the rate of fertilization if you aren't getting a bloom.

http://www.suttlefish.com/fertilizing_pond.html

The people who gave you advice are both right technically. You can keep fertilizing, but liming works in conjunction to make the bloom happen.