The dechlor is the sticky wicket 'cuz chloramine doesn't evaporate off like regular free chlorine. That's one of the reasons that the water treatment folks use it, it lasts longer. To get rid of it you have to break the chemical bond between the chlorine and the ammonia that is used to prepare the chloramine. Once that bond is broken you then have the ammonia issue to deal with, so you have to use a dechlor product that does it all or else have another way of dealing with the ammonia.
How about a bog garden sitting above the elevation of the tank so that you could just let gravity do the dripping after your water is degassed by the biological filter You could use a cheapo digital sprinkler timer (battery operated ones run all summer on a pair of AA's) to fill the bog and let the timer control the filling of your bog. Install an over flow just in case the pressure changes and you get more than you bargained for. The higher pressure fill line from the timer to the garden vessel can be fitted with a liquid fertilizer Bernoulli effect uptake that you could add a liquid dechlor through.
The garden vessel could be anything from a drilled spare tank to a peach crate with an EPDM liner, depending on your tank size. You need about 6" of washed gravel and some plants (Gunner has been modding AC filters to grow Pothos plants as a denite filter with very positive results).
The bog could be set directly on top of the tank or off to one side or even in a different room I suppose, but it needs to be above your tank. The outflow from the garden could then be regulated by some Walmart drip emitter valves.
I know that the bog works because we use them to filter our Koi ponds, and Koi are right up there with Trinidad Plecos when it comes to generating fish poo.
The 4 zone timer was $20 at Costco / Price Club, emitters are about a buck at Walmart, along with the feeder intake and a filter - another $3-5. A large pot of Pothos at H.D. or Lowes house plant dept. would run around $10 and the rest is gravel and whatever you decide upon for a shallow vessel.
Seems that it should work great 'cuz you're off of the grid - only dependent on the sun, water pressure, gravity and a couple of AA batteries - plus you get the added advantage of the house plants making oxygen for your fish room and there's nothing to buy but dechlor and a pair of batteries every 4-5 months. The whole thing might cost $50 if you had to buy the gravel, lines, vessel, etc.
Use an old toilet tank (the older ones hold as much as 10-12 gallons). Install the dechlor feeder on the supply line, plug the hole where the flapper is with a piece of acrylic and some silicone and use the tank bolt holes to silicone in some rubber stoppers to hold your drip hoses. Already has a float valve so you wouldn't need the timer. Drop a heater in and you're ready to go.
I haven't the foggiest if this would work but I thought it might give some ideas to play with.
or- Keep the bowl attached, fill with gravel and plants and siphon your drip from the bowl. Then you've got the neighborhood talkin' about the crazy fish guy with a toilet hanging on his wall.
