I almost felt like adding "and me. This sort of thing is my bag baby" to the title as it reminded me of a quote from Austin Powers.
I have read that it is advisable to have a pump that can circulate twice the amount of what the FT holds. So if I have a 275 gallon tank then I should get a 550 GPH pump. Is that a minimum requirement or can I opt for a higher volume pump like 600 to 800 GPH? With that said what fill and drain rate should I aim for? I know I can use a ball valve to control the output but is there a general rule of thumb recommendation that I can use as a starting point? Also can you recommend a brand to look for in regards to the pumps? That would be helpful.
I am also contemplating if I should cut the IBC as many do which would yield a grow bed and a slightly smaller tank or should I simply cut a medium opening in the top of the tank (for accessibility) leaving it primarily intact? I have two 30 gallon containers which I will use as grow beds and will pick up more as the system matures. I just figured that leaving the tank intact is beneficial because the of the water volume level will remain relatively consistent temperature levels. Any thoughts, comments or recommendations are greatly appreciated.
Larger is better, but larger costs more to operate. The initial price of your pump pales in comparison to the cost of operation so look for efficiency.
My experience shows that the water flow is not critical. I'm not saying a trickle is going to work, but I ran my 800 gallon system for months at about 200 GPH without any problems. My density is about 37 lbs / 800 gallons total system volume which is pretty low in comparison to many other systems. So it probably hinges on the density you intend to maintain. My low density might not work for some plants that require more nitrogen, so what you intend to grow also comes into play.
But to be safe you should probably just follow the Rules of Thumb document until you have more experience. Don't worry you will have an opportunity to replace your pump before too long. They don't last forever. Even the external pumps wear out way too fast.
I agree that Larger is better. I have never had an issue with Pondmaster pumps. Don't worry about the pump moving water too fast. You want to have the power to run multiple beds and instead of restricting the flow with a ball valve, you can divert the water flow with a T fitting to a spray bar. The spray bar will aerate the water in the FT and then you won't be restricting the pump as much by closing off your pipes.