Water lily feed?

I'm growing a waterlily in a large pot, will it need feeding? If so, how?

 

I use these.......
http://www.jbl.de/en/aquatics-freshwater-products/detail/2346/jbl-the-7-13-balls
Either scatter 6 or 8 around the roots when you plant it up or poke them down through the soil if you've already planted it.

 

Thanks Catz, I'll look out for some!

 

Most aquarium shops have them or similar. They are nice because they work underneath so don't turn the water green.