I've read from many sources that recommend you have a filter gph that is 5x your tank size in gallons. My question is:
How can I achieve this and still have a slow flow tank for fish such as bettas?
I've found that anytime I follow this 5x rule of gph I end up with a fairly strong current in my tank. Does this rule only apply to HOBs since they notoriously over state their actual gph?