Ok. So you have 2 7gallon tubs. Here is two choices:
(1) Use the tubs separately as individual systems.
-Benefits: You can grow different strains more easily since each
plant has its own reservoir and can have a unique nutrient program.
Also, if one plant gets a root disease, it can't share it with the other
through the reservoir since they're separate.
(2) Combine the 2 7gl buckets together.
-Benefits: More nutrient solution VOLUME = More stable PH
less maintenance, less checking pH and adjusting. Would recommend
growing the same strain since they share the same nutrients.
As far as a pump, I love my GH Dual Diaphram pumps. Its got 4 air hookups
so 2 stones per bucket. It's also VERY QUIET. Most people will probably say
it's overkill, but the water turbulence helps move the roots in solution, allowing
more air to get to interior root areas and increase overall uptake.
