You could easily still have a lot of suspended water in your bio. I have three tests, performed while I still have my bio spray drying at 140F. One is to put a sample in the fridge and do look for wisps of moisture suspended when it gets down to temp. Another is weigh-heat-weigh, where I weigh a sample, heat in microwave until around 220F, weigh again. Yet another method is the vapor test where I place a shallow container with the bio in it, such as a tea cup, and set a small square of glass on top, heat to 220F, and look for a ring of condensation around the rim. I don't think clear bio is an indicator of moisture free or soap free,for that matter.

My batches are less than half of yours, at 45 gal., but what I do to dry is circulate in my drum processor with a spray dry fitting until it reaches 140F, shut off heat and continue circulating. Takes around 2 hours depending upon ambient temperature.

Like this (except that I have a spray dry fitting screwed in which fans out the bio):



Spray dry fitting at top of photo:



Hope this helps.