That sounds ambitious....the water change water butt thing sounds good -
certainly better than carrying buckets outside to throw them on the
plants...

I've not come across undergravel heating over here...what's that all
about?

Thanks
Gill

AFAIK it's the same type of deal used in seed trays etc.
One or more waterproofed (natch !) heating elements in cable form to heat
the soil/gravel.

I've heard it's very good for planted tanks, though I don't think it's for
me.

Peter