I am trying to decide between a 50 gallon Titan replacement tank or a 28 gallon auxiliary tank added to my bed.My thinking is the Titan is probably best except for one thing, I put very little use or miles on the truck for 8-9 months of the year and I am worried that 50 gallons of fuel could go bad in that kind of time frame.I always keep my tank full or as close to full as possible inorder to prevent condensation in the tank, and 50 gallons will sit in the tank for months with the occasional top off.If I went with the auxiliary tank I am thinking I could leave it dry for the idle time and only fill when I am traveling for the 2-3 months pulling our 5ver.I have a 2016 F350 with a Reflex roll up bed cover so the auxiliary tank will be small and in front of the hitch, but below the bed cover. I have priced both and the cost installed the way I want is pretty close with either tank.So I am looking for some advice from those who may be more knowledgable or experienced and would appreciate any comments on my decision. Thanks for your thoughts.Keith

I have a 30 gallon tank in bed. We only use in spring, summer, and fall. In the winter I keep 5 gallon so the tank has some action to help keep clean. When I need fuel I use the 5 in the bed tank and fill the underbed tank and put 5 gallon fresh fuel in bed tank. No problems in 12 years.

We have an 85 gallon aux. tank with an electric pump for over 30 years. When traveling we buy diesel fuel at best price for the distance. When at home we empty it then refuel wih gasoline for the car, mowers, again at our price and convenience. Buying fuel in volume saves up to 20% Payed for that tank in no time. My truck is our gas station.

I have a 60 gallon auxiliary tank in my truck. Bought it when my truck was brand new. Best upgrade I have done so far. My truck is used almost exclusively to tow, so it also sits during the winter. I haven’t had problems with fuel sitting yet. If I had a short bed I would probably want the replacement tank to save bed space. But that is a lot of cost for not a lot of extra capacity.

I would not worry about condensation especially in Florida where the temp changes are not that drastic. I have a 50 gallon Titan in an 08 Duramax. I have 150K on the pickup and no issues. I would not want to lose the bed space but to each their own.

Have a 40 gallon in bed tank. Enough to tow all day

Help with auxiliary fuel tank decision or replacement.

Lynnmor
Explorer
Sep 25, 2018
I like my fuel range with the 50 gallon Titan tank for yet another reason. I live in PA where the fuel taxes are the highest in the nation, so for two years now, I have bought exactly one half tank of fuel within the state. My last camping trip is an example, I took two 5 gallon cans along and went the entire week without giving the greedy governor a dime. After returning home, I travel a bit farther to a station out of PA to fill up the truck and any empty gas or diesel cans. While out of state, I also buy groceries other items.
Trailblazer87
Explorer
Sep 25, 2018
I have a 60 gallon RDS tank with to box, it gives me more than 12 hours of drive time with the trailer. So plenty of time to find a campground, go do our touring, then find up before fueling and hooking up and moving on. I consider it a convenience that I can choose when to stop on my terms and not when forced to by necessity.
larry_barnhart
Explorer
Sep 23, 2018
fj12ryder wrote:
Peggy bought mine for Christmas and it was a couple years before I installed it. I finally did because the last trip I was off on the two lane roads a lot and got tired of trying to find fuel stations that I could get into and out of easily. A fair amount of wasted time finding a station and then discovering I couldn't get to the diesel pumps without a lot of jacking around. Immediately after installation the stress level dropped a bunch.

However now we only travel 250-350 miles in a day and could probably get by without the tank, but when we were doing 400-500 miles a day it was a godsend.

same for us. Never look for a cheaper price just easy in and out.

chevman
fj12ryder
Explorer III
Sep 23, 2018
Peggy bought mine for Christmas and it was a couple years before I installed it. I finally did because the last trip I was off on the two lane roads a lot and got tired of trying to find fuel stations that I could get into and out of easily. A fair amount of wasted time finding a station and then discovering I couldn't get to the diesel pumps without a lot of jacking around. Immediately after installation the stress level dropped a bunch.

However now we only travel 250-350 miles in a day and could probably get by without the tank, but when we were doing 400-500 miles a day it was a godsend.
Cummins12V98
Explorer III
Sep 23, 2018
Kevinwa wrote:
Cummins12V98 wrote:
I personally don’t care to extend my range. 250 miles or so we stop for fuel along with other reasons. Just carry the 5 as a backup.

Exactly, you and I were after two different things, I wanted extended range between fills, you wanted emergency fuel. Hope I didn’t offend, I just was pointing out the difference.

No offense taken!

I think everyone should try without an auxaliry tank to see if they really want one.
Kevinwa
Explorer
Sep 22, 2018
Cummins12V98 wrote:
I personally don’t care to extend my range. 250 miles or so we stop for fuel along with other reasons. Just carry the 5 as a backup.

Exactly, you and I were after two different things, I wanted extended range between fills, you wanted emergency fuel. Hope I didn’t offend, I just was pointing out the difference.
Cummins12V98
Explorer III
Sep 22, 2018
I personally don’t care to extend my range. 250 miles or so we stop for fuel along with other reasons. Just carry the 5 as a backup.
Kevinwa
Explorer
Sep 22, 2018
Had the Titan installed in my 2016 F350 early this spring. Love it and glad I went that route instead of the in bed. Only one tank to fill. No thoughts, just fill. I have Almost tripled the towing range of the F350 with this as I typically refuel when I have 20-30 litres remaining. So now I have 170 litres of useable fuel before fill and before I had 70!

Best addition to my truck ever.

And the 5 gallon jerry can that was suggested earlier doesn’t even compare. You aren’t extending your range with that, just carrying some emergency fuel. Not the same thing.
Dave5143
Explorer
Sep 21, 2018
I had an RDS 30 gallon aux tank installed on my F250 earlier this year. I love the flexibility the extra fuel gives me in planning my fuel stops. One thing I discovered about my truck however is the fact that it seems to have a vent on the top of the internal tank. I discovered that the hard way when I left the manual valve open. What a mess. I installed a solenoid valve in the fill line and wired it to one of the upfitter switches in the cab. Now when the gauge gets down around 3/4 of a tank I'll turn the valve solenoid on and watch the level slowly rise while I'm driving without risk of overflowing the internal tank. If I forget to turn it off when I cut the engine no worry of overflow since the circuit is only hot when the ignition is in the on position.
For me the aux tank was the cheaper option even though I had the aux tank installed professionally.
Grit_dog
Navigator
Sep 21, 2018
You got it backwards. Condensation is pretty much a myth with plastic tanks, but is a concern with a metallic slip tank. Besides, just run em down low and fill when running the truck again.
I've never subscribed to the full tank for storage theory and I shelf many engines every year off season. Fresh fuel (especially if talking gas, not so much for diesel) trumps the potential of moisture IMO, in most cases.