Hey Polly!
Glad you could join us! I use the waterlily baskets and plant my waterlilies in pea gravel and then top off my pots with egg rock so that the koi dont' get the pea gravel all over the bottom of my pond. I love the once a year fertilizer stakes. If I had to ferlilize the waterliies every month, it is a chore that just would not get done. Hardy waterliliies need temps in the 60's to send up any flower buds. I typically divide my waterliies in the early spring when they are still dormant and do my fertilizing at that point. Additionally, I have read that waterlilies like to be in about 2 feet of water. I will tell you that mine are in about 3 1/2 feet of water and I have no problem with my waterlilies flowering.
When planting your WL, make sure you don't cover the growth points of your waterlilies. You can use a number of diffierent mediums to plant your WL. I have seen a number of people that use the unscented 100 % clay kitty litter and I know there are aquatic wl mediums that you can buy too - these however tend to be rather pricey.
I do not have tropical waterlilies, so hopefully somebody will jump in with their experiences.
Carolyn
