Blichmann Thrumometer...I should have read the fine print

So I bought a Blichmann Thrumometer online thinking I could put it between my BK and pump to monitor the recirc before going into the fermenter.  I had to check my temps with a digital stem thermometer about 20 times last Sat before I got it down to transfer temps.  The Thrumometer showed up yesterday and I noticed a tag on the side that says “Do not exceed 140 deg”.  What a bummer! :'(  I guess I’ll have to figure out a plan B.  Any sugestions?
-J.K.L.

morebeer.com has an inline oxygenator that is just a series of stainless T’s that you screw an O2 stone into one end, a thermometer at the other and  a nipple for the flow to come in,  Terrible description but here’s the link:
Inline Oxygenation Assembly (No Barbs) | MoreBeer