Thanks,
One experiment few ever seem to take upon in this hobby, light limiting.
Like the limbo, how low can we go?
For all the banter and carrying on about limitation of CO2/NO3/PO4/Fe etc, why have not folks tried do this more often?
I do this with shade cloth at the lab, many horticulturalist do this at the nursery.
Old scholl Dutch and European tanks tend to have 2w/gal or so.
Knowing what we know from a high light/high CO2 system concerning nutrients, then applying this knowledge to the low light tanks, affords us the best of both worlds and gets the most efficacy out of the lights at lower levels.
If we attempted to test and analzye at low light, many things would allude us.
It would take longer for one.
Second, the test kits would be required to have a higher resolution/accuracy level to detect changes.
Third, algae responses are intensitfied at high light, eg: not many folks had Green Water till PC lighting came along.
CO2 demand is driven by light and available nutrients(EI addresses that).
So less light= less demand and more wiggle room with CO2 dosing.
The arguements are very good for this exploration, but consensus dating back 60 years suggest 2w/gal is fine for most any plant.
Which is low by today's standards and about high med by standards 20 years ago.
Regards,
Tom Barr