There are more than a few problems, or at least challenges with this. The rub to larger and more efficient and affordable pumps has been that our very commonly undersized sumps, for starters, can't handle the flow quietly - presuming you drill an adequate sized hole to begin with. The same problem (oversized sump return pumps) has led to unduly creative overflow modifications on the display to quiet the push (a push, by definition, since the bulkheads are designed to handle half flow or less but are asked to commonly do more...hence siphoning air, etc and noise).
Then there is the issue of having all of one's eggs in the same basket. As the pump ages...all outlets dependent on it suffer. And if the pump needs cleaned or fails, everything suffers while its down (circulation, calcium supplementation, chilling in this case, aeration by gas exchange from water turnover), etc
i honestly feel it is a serious mistake to have a single pump solution. And if you must, please have an adequate backup pump waiting and shut off valves and slip unions flanking the running pump for quick swaps for cleaning, replacement, etc.
The best solution, IMO is to have one large pump on a closed loop for the display (or comparable stream pumps to do this job). This is the heavy duty for flow in any system and the cause for noise. As a closed loop (or via stream pumps) this is now quieter (very quiet actually) versus the toilet flushing trend of vigorous sumps in recent years LOL
Then a second pump in your sump can do balance of flow duties as you'd hoped...chiller, gentle display loop/return, etc
