I have in inground Rubbermaid stocktank pond (300 gallon).
I had a waterlily in there that I had divided just last year. Also in the pond were 2 water irises......one of which got way too big over the summer.

I think I lost a fertilizer tab into the water, while feeding the water lily. Then duck weed went crazy. Then the water lily totally quit........maybe put out 1-2 leaves, but no blossoms.

I cleaned up the pond today. There were alot of tadpoles, which should have eaten the duck weed.......not sure why they didn't.
Question: Why did the waterlily poop out? When we pulled it out (was in a 7 gallon container), half of the container was still dirt.....no expansion of the water lily. There was a growing point putting out little leaves.

Could the overgrown water irises have been taking all the nutrients away from the lily? Could the duck weed covering the entire surface have shaded the lily too much?

I've been growing lilies in this pond for quite awhile, and I've never had one act this way. Never had such a huge water iris in with it either.
I had been fertilizing the lily ever 3-4 weeks, prior to it pooping out.
Any ideas?
Thanks.