TSoul, welcome to the website and congratulations on your new Cresendo. I am sure you will enjoy this forum as much as going out Rving in the new rig. I believe the my gray and black are only 65 gals each and it would be nice but not a must to have to have larger. When you get the time and tanks have been dumped. Fill each with fresh water untill absolutely full and then measure with a five gallon bucket under the dump vlave how many each tank can hold. This way you will know what you have. The level sensors and or monitor can be adjusted to be close to the level in tanks. Tissue can give you a false reading in the black tank so a trick has been to pour about five gals of ice into a 2/3 tank of fresh water in the black tank just before you leave and while driving it will bounce around inside tank and clean the sensors; ice melts and when you get to your destination you can dump the water. Good luck and injoy!
Mike, Amy & Muffin, Full Timers
RVSA Certified Master Technician
iRV2.com -Gulf Stream Owners Forum Leader
2000 Scenic Cruiser
99 Chevy Silverado 4 X 4 Toad
2006 Saturn Vue AWD Toad
NASCAR #3 & #8