That would be extreme underfiltration. I would say a 5-6x turnover per hour would be a fair minimum to consider, and that would be 120-144x per day...I am bad 12-15X tank volume per DAY I am sorry about that. Fishman you are right thanks for calling me on that.
This is a growout, according to the OP. I would agree on that high of a turnover if they were trying to keep it in there for life, but for a temporary setup, that's a bit much imo.I try for 10x per hour. IMO a 55 is too small for an adult Oscar and needs a 75. On my 100gallon (with an Oscar) I run a wet/dry at 1000gph. Allowing for return length and bends puts it more towards 8-900gph as the pump is a 950gph and secondary is 280gph. On my 90 with Oscar, I run 2 Emperor 400's