Here is a side by side comparison. Only thing different in the input of the two analysis below is bulb efficiency. As you can see in the results, it affect the dosage considerably (highlighted in red). Generally, cheap bulbs are lower efficiency and thus, one must reduce flow in order to regain UV dosage.
So even though they're the same wattage the one with over twice the efficiency produces over twice the dose....... Interesting.
Could a guy change from a lower efficiency bulb to a higher efficiency bulb and expect to see similar results without changing anything but the bulb????