I've read a lot about water gardens and it all sounds so easy but no one talks about keeping the water clean. How can I keep the water clean for my lily and lotus that are in containers? I read that the water only needs to be refilled and not changed. I started with new clean containers but the water keeps getting a layer of scum. I've repotted several times now but I'm still getting that slimey green stuff and a really thin layer that looks oily. I've used a tiny skimmer to scoop out debris, changed the water, changed the soil type and it continues to get nasty. I moved the tub to the greenhouse so nothing blew into it but the same thing happened. I've tried top soil, river mud, kitty litter (which was way cleaner) and no mater what...the water gets scummy on top. I began to think our well water was the problem so today I started the new Helvola lily and dwarf lotus in spring water and distiled water until I can gather enough rain water to bring the water level up. Aside from the slimey problem there's a lot of stuff carried by the wind out here in the country. Once the leaves fill the pots i don't know how I'm going to be able to skim the debris from the surface. Am I fighting a losing battle?
I just use large river rock. About 1 or 2" pieces. No soil of any type. My pots are in my pond which has filtered water flowing thru all the time so don't know if this will help. I have never fertilized a plant in 4 years and they keep growing.
Still or stagnent water will form scum or algae I'm sure. Maybe if you create a way for water to run thru your plants it will clear up. Otherwise I don't see any alternative than water changes all the time. Sorry I'm not much help.
Every now and then I stick the hose in to let the surface water flow over the edge for just a minute. Nothing magor. I also add tadpoles. They keep the water sparkling clean and eat the fallen debri. I never use fertilizer in my smaller water bowls. Just tadpole poop and natural organic breakdown.