Hi Devonm2012,
I had the same problem of loosing boiler fluid in the expansion tank
and replaced it with the CAMCO,pink boiler antifreeze(concentrate,to be diluted) from Camping World.PS:I found NO leak.
But you can contact the OASIS people:
Siggy
OASIS:
====== “ RHOGUARD”, boiler antifreeze, or CAMCO boiler antifreeze at CW.
Call Precision Temp they will ship to you
in 1 gallon containers.
Service Manager/PrecisionTemp
513-641-4446 ext. 109
800-934-9690 ext. 109
Fax 513-641-0733
Email: gwulfmeyer@precisiontemp.com