On the manual, not sure where you found yours, but it may be what we have which we have in our FILES section.
In case you have not yet found our FILES section, there is a lot of great resource info in there. Including most all of the sale brochures from way back when, owners manuals, appliance manuals and other good stuff.
The sales brochure has a lot of good info on your model camper that is hard to come by in one organized spot. Just scroll to your year and download a copy. Same for the owners manuals.
To get to the FILES section, you have to be logged in. Look up top along the forum for the words "FILES". That is a tab, click it. Then select the area you want to go to can read on for hours, days, maybe even weeks...
A heads up, RV camper owners manuals are not like an automobile owners manual that gives exact instructions on most everything in your auto. The camper owners manual talks more in general and things to help you along the way. For the actual appliances, there are owners manuals with very details info on them from the manufacturer of the appliance. We have many of those in the files section too. If your model is not there, give us the make and model no. on the appliance and we can help search for it too, then add it to our files section for future help to others.
You are also welcome to ask any and all questions about your camper. Just create a post in the appropriate forums and ask away. We have many areas already answered in old post, but we have no problem with asking questions you need help on.
To the tank capacity, in the FILES section is an area called Brochures. Go in there, scroll to 1994, and download a copy. Then look for the T1850 travel trailer spec chart for the tank "system" capacities.
I'll explain the wording they used with "System"
The 94 T1850 has:
24 gal. fresh water system.
25 gal, grey water system.
25 gal, black water system.
All rated capacities are approx. But, heads up, they are talking about the system, not the tank in all cases. The fresh water system includes the tank, the water heater and all the fresh water piping in the camper which is filled with water once full. The water heater holds 6 gallons and pending the floor plan, the PEX piping may hold 2 gallons. 6 + 2 = 8 gallons - 24 gal. = 16 gallons can be the fresh tank size. You can only draw out with the water pump close to the 16 gallons or until the pump dry locks and will not pump the last few gallons.
I am not totally sure the 1994 camper fresh systems are this way, I believe they are, but for sure the year 2000 and newer are. I did the math on the cubic inches of my tank and others (2004 to 2007 models) and then never lined up close to the brochure thinking they where tank sizes. Then it dawned on me, I have a 32 gallon fresh tank, 6 gallons in the water heater and 2 gal in the pipes. = the 40 gallon "system" capacity in the brochure. And when I had the tank out, it was stamped 32 gallons on the tank. The weight sticker calls out the 40 gallons of weight if the system is filled.
The black and grey tanks, do follow the system rating fairly close. Waste water doers not normally stay in the pipes, it all drains to the tank so those tanks are the system water holding capacities,
Hope this helps