Water temp above 75F?

Because it has lots of healthy leaves I assume there's no problem with a build up of salt or other minerals.

I've never really been a fan of the concept of phosphate = blooms so more phosphate = more blooms. To me as long as the plant has enough phosphate it should bloom. Jobe's fruit tree spikes should have enough phosphate imo for blooms. But I don't know how much/often you're fertilizing.

I'm not sure pushing a stake into the soil would be a good indicator of being root bound. I kind of go by the overall size of the plant. If it gets smaller each year I assume root bound whether true or not. But I also don't know if being root bound reduces blooms or not. I assume so, but don't know.

Hi
I generally find that I have to repot at least every second year . Tends to make offsets rather than flowers with much less quality . Find that true for almost all kinds of water plants . I often deadhead to produce higher quality individual flowers rather than multiples . I can go from 6 inch
flowers to over 14 inch standing two feet out of the water.
i do use high phosphate for the process.
Haven't done it this year due to other projects and having a really bad flowering season
You might try high phosphate ferts but suspect you need to thin . ?? i find pots essential because most water plants are very invasive Good luck with whatebver you decide!! gary

Thanks waterbug guy and Gary.

How would I thin this bog out? Would we just start digging and pulling? I suppose I could pump out the 8-10" of water on top of the mud first. It's not like we can stand on the mud and dig. It's going to be a challenge. And if it's like my previous potted lotus, there might not be any soil left.......just roots and tubers. Does that mean we'll have to find a bunch of new soil to add?

This is a 300 gallon stocktank, so it's about 5'x5 and 1/2' big.
Thanks for your input!

I currently have a 100 gal Rubbermaid stock tank 1/2 buried and I sure can't move it. I grow Canna in mine now but this is how I handle dividing containers I can't dump:

I stop adding water and let the soil dry out some. Here in Phoenix and when I lived in Texas I do this in the summer when plant growth slows down from the heat. In San Jose CA and NY I did this in the fall or spring.

When the plants die back and I cut off the foliage. When the soil is still moist I dig out any soil I can with a small hand shovel and a flat pry bar.

If I've really got a problem I use a standard pointed shovel and dig just like in the garden. I start in 10-12 from the tank edge so the chunk of soil comes out between the shovel and tank edge. That seems to do the least damage. I really just use the shovel to kind of loosen things up and then I can go back to hand shovel and pry bar. The pointed shovel does cut tubers but I've always ended up with more than I needed so loosing some was OK with me. Hopefully I get lucky and don't cut the biggest tuber.

Not saying this is the best way, just the only way I know. I do know I do not like digging in saturated clay soil at all and I always did a lot more damage to tubers.

For soil I've only ever used backyard soil. I dig down a bit before the top soil. I've almost always lived places that had a lot of clay. I put the waste soil from the container into the compost, I don't like to reuse any because of mineral build up. I don't know if there's better soil, it's just digging in the yard is convenient and as worked for me so far.

Hi
Would assume you're growing temperate lilies?? i grow tropicals and not sure how different they are . ??
I find they need enough water for pads to float or they "stack " resulting in poor flowering and if crowded tend to offset, again resulting in poor flowering. Does that apply to temperates??
if you separate now will they have time to recover before winter?? I think i would wait until spring and then change the entire method ?? Sorry i can't be of more help gary

Try tossing four handfuls of wood ash into the places where you see new aerial lotus pads beginning to rise.

After six more pads develop, expect buds to rise.