Thanks. Ye my cab is only 4ft high, minus 8 inches for filter and light, minus another foot for 3L airpots at the mo.
Bit worried that 8.5L will produce such a healthy root system that i'll get a canopy that i don't have the lighting power and space for.
Thinking of making my own autopots, i'll have to have a look at their 'aquavalve' and see how it works.
Cheers,
steely