Hi Mike,
Rule number 1 is that Light causes algae, so reducing light will ALWAYS help to reduce algae. Will it solve the problem completely? Maybe not but reducing the light intensity is an important first step. It lowers the stress and makes all the other things you do more effective.
The 10X rule is based on filter ratings and takes into account media and all the things that cause drag. The rule is aware of filters only delivering half it's rated flow, otherwise it would be the 5X rule.
240 x 10 = 2400LPH target flow rate. 1700+1350 = 3050LPH so this is fine.
As you mention, the problem might be the reactor, but only if the spud is the old type 12mm diameter. If it is the new type, 16mm then this will be the same diameter as the filter spud and the flow reduction will not be a major factor other than the bioballs inside, so yes, you have a point, he might remove the balls to improve flow. That's a good idea. :idea:
Cheers,