Pipeline shows 0 records found?

If the field you are comparing to in native, Quickbase is a duration field then you're being tripped up by the unit of measure issue. There is some possibility that if you compare the range to 75 days instead of 75 it might work. But if that doesn't work, then I suggest you make a new formula numeric  field in native. Quickbase called [duration in days]; with the formula of

ToDays([My duration field])

that will give you a nice clean numeric field to use for the comparison in a pipeline  

Just set up a formula numeric field like you suggested and it worked!  Very strange.

I've ran into something similar with trying to determine if a record is less than a duration value. I'm not sure why but it appears the function for seconds is adding zeros (000). When you set the duration field to seconds, it will display appropriately. However, if you use the formula builder, you'll see 3 extra zeroes added. This value is also true in pipelines, even though you might expect the value for a full day in seconds to be 86,400, you'll get 86,400,000. 

One of my examples was to look at something within a duration of 4 days. In pipelines if I multiple the total seconds by 1000, I get results that I'm looking for. 

Very strange indeed. 

When you say that you sent the Duration field to seconds, that means to display as seconds.  That affects the formatting of the display but does not affect how its stored.  So it's good to  know that they store durations in milliseconds.