I recently spent some time up near an active volcano in northern CA, about 3 hours from where I live. They have boiling mud pits, fissers, hot geyers etc.
Lots of geothermal activity.

The new weed:



Not sure if it'll grow weell in our tanks this way, but.........Iv'e seen it all over in very different temps terrestrially.

Pretty flower too.
Really a noticable bright lime green in the rivers.



and





There is crow's foot in there also.

You can see the large yellow emergent stands growing out of the water, but other patches that are growing underwater and they are permanent.

This is one of the few places in CA where the water supply is constant.
It's also constant temp and CO2.