The Fish Works Guide to re potting water plants
Repotting your water plants is easy. All you need is some overgrown water plants, water plant soil, some spare pots and some newspaper1) Line the pot with a bit of newspaper that will block the holes of the pot.
2) Separate an individual water plant that has grown out of its pot. Try to cut the plant so that it retains much of its new growth roots. Cut-away any old growth leaves.
3) Place the root ball of the plant (if there is no root ball, then just dangle the roots into the pot, holding the water plant at the eventual level that you wish to have the plant sitting.
4) get handfuls of soil and sprinkle the soil into the pot so that it will support the plant at the right level.
5) press the soil down and keep filling until the soil reaches around 20mm below the top rim of the pot.
6) Fill in the remaining 20mm with gravel (this will prevent your naughty fish from digging into the water plant soil!).
7) Place the water plant into the conditions that particular species likes (sunny? shady? correct water depth etc).
8) Hey presto! You have done it!