"OdorSafe" hose is stiff as an ironing board!
It should not be heated to bend it tighter than it wants to go willingly (no hose should be, 'cuz it weakens the hose and can cause it to collapse and kink). Unless the gray pvc fittings are barbed at both ends (which I've never seen...they're all threaded at one end, barbed at the other), they can't be used as inline fittings. You don't want to use them at the tank either, 'cuz although they're called 1.5 thread by 1.5 barbed, the barbs are actually 1 5/8"--making 'em all but impossible to get a hose onto. So be sure to use only nylon or marelon thread-barb fittings at the tank.SeaLand has 90 and 45 degree inline radius fittings, which are what you need between the toilet and the tank. They're hard to find in boat stores, but you can call 'em Monday (800-321-9886) and ask 'em to fax you that page from their catalog and order 'em direct. They're component fittings, so you'll also need some pvc cement. To get hose onto a fitting, warm it with a blow dryer (use a heat gun ONLY if you really know what you're doing with one...'cuz overheating sanitation hose will damage it)...use a little dish soap on the fitting and the inside of the hose. Do NOT use ANYthing oily...you'll have a permanently slippery connection that can work off the fitting. Double clamp (iow, use two hose clamps) all connections...the screws on the hose clamps should be on opposite sides of the hose. You say you have a lot of tight turns between the toilet and the tank...that's not good, 'cuz every turn is a place for a potential clog. The shorter and straighter the run from the toilet, the better Can you re-route the hoses to straighten it out? If the total feet of hose between the toilet and the tank is longer than 6-8', I strongly recommend that you find another location for the tank. Tell the folks on the Sabre list I said "hi!" If there's enough discussion and questions, I'll be glad to join the list again to answer 'em.