You're welcome Aquarist14!
Thank you for the compliment - it was about 8-9 hours of straight work!
If you have no bubbles (or leaks) then I think it's safe to say all the CO2 is dissolved so yes. If you have bubbles of CO2 that dissipate into the air, then you are losing some efficiency.
Decrease flow? No, it's a straight shot through with a ceramic liner so nothing gets in the way of the water flow - A reactor may because it's not a straight shot. I don't have experience with those so someone else can give you that information. Honestly, the lily pipe intake is probably a huge reducer of flow because of it's design. The water was instantly clear so I'm not worried.
For the purposes of CO2 injection:
During the day, injecting CO2 causes a drop in pH as it dissolves in the water.
At night, the CO2 is turned off because the plants are using O2 and giving off CO2 - thus the pH would drop even more if the CO2 were to be injected at night. There is also the danger of gassing sensitive fish. Furthermore, pH swings are bad - fish can be stressed by them so people set up their CO2 to turn off when the lights turn off so the pH is more stable and no gassing fish.
The pH controller in conjunction with CO2 injection can accurately control the pH of the tank and it will stop the CO2 if the pH drops too low even during the day. By comparison the timer I have is dumb - it will turn on and off at a preset time.
CO2 tank depends on your situation. Larger = more time between refills, but is heavy and bulky.
For me, paintball tanks are more convenient because I live in the city, I have no car. Renting one to pay $3 to fill my tank is redic... and lugging around a heavy 5-25 lbs CO2 tank is not something I will do
I purchased 3 24oz (2lb) CO2 tanks for paintball and I can walk into any sporting goods store that sells paintball and have them refilled. They are portable for those of us who use feet and metro/subways. The larger tank is great if you have a car.
I think that people may be installing the inline diffuser too closer to the exhaust and the bubbles don't have time/distance to dissolve. I gave my system (see the video) an additional space before the Hydor inline heater. I think that distance was enough to allow the CO2 to fully dissolve ~4-5 feet. I can try to measure it if you want. But at 3bps there are no visible bubbles which is what all of us are shooting for.
I think the reactors are great and if I had space and trust in my building skills I'd tackle it. There are some really cool ones that people have built on here.
For me it was an easy choice: $38 for my time, effort involved, and peace of mind.
Let me know if you have any questions about my equipment.