Indeed. Having no filters is permanent, but the plants are temporary (except the floaters). The plants will suffer from lack of nutrients. Liquid fertilizers don't work as well on heavy root feeders. I'm surprised the peace lilies have lasted for the last two months, and may last much longer, but I did pull them out and clean off a few dead roots and brown leaves. They are blooming underwater. I have no idea how long the mondo grass will last, but will find out. Of course the creeping jenny does send out roots along the stem and can survive underwater in the right conditions. It still prefers to be emersed. I'm considering mimulus (monkey flower), if I can find it at a nearby nursery. It too may last underwater for a month or two. Having fun water boarding plants. :}