I put my tropical Nepenthes in large aquariums. I cover the aquarium
top with glass. There are some gaps for ants and things to climb in to
the aquarium - it is still quite humid inside the tank though. My plants
are in separate pots each, which sit on top of upside down pot bases or
other support to keep the bottom of the pots above water level. I also
put shade cloth over the whole of the aquariums so that the sunlight
doesn't destroy the plants (quite intense sun where I live).
My plants are grown in peat with dead spaghnum spread around the top of
the pot. The plants have handled tap water without any problems here so
I just use tap water to water them about every three weeks because water
in the pots slowly evaporates through the gaps. Algae builds up very
thick but I don't worry about it and the plants don't mind it either.
The pitchers sit either on the upside down bases around the pot or in
the water supported by the thick algae. Most pitcher buds get immersed
in the water but they always grow up without any problems. The growth
rate for my plants are incredibly fast inside the tank and the pitchers
get pretty big. This has worked for plants like x rokko, rafflesiana and
related crosses, thorelii, mirabilis - all fairly hardy. I found that
plants like ventricosa, maxima, albomarginata did not favour the
conditions in the tank - probably didn't like the fairly high
temperatures inside.
All the best,
Kenny Leong.