Hi,

My project for this summer is to grow a tropical water lily, that will spend
the "hottest" months outside in the sunniest place on the patio. Hopefully
this has not consigned us all to a cold summer ;-)

I have a large black tub to grow it in and will have an aquarium heater
installed to keep the water temperature warm enough on colder nights, but I
know that algae will grow rampantly in such conditions.

So I wondered whether the black dye used to colour water in Kew's pond was
available to buy, and if so what it is? They added it to stop algal growth
and it obviously didn't affect the plants. (Saw it on "A Year at Kew")

Any ideas, or has anyone tried using it?

TIA
Marina
E. Sx