There's a MUCH simpler solution for about $20
If it'll even cost you that much...'cuz all you'll prob'ly have to buy is a few feet of 3/4" hose and tee fitting. On many sailboats, the head sink drain already shares the same through-hull with the toilet intake. Even if the sink drain through a separate through-hull above OR below the waterline, there’s certainly no reason why the sink on any boat can’t share the same through-hull, provided the toilet and sink are on the same side of the boat, and the head intake through-hull is close to both. If they are, it’s a simple matter to tee or wye the sink drain hose into the head intake hose next to the seacock; both hoses are typically the same size: 3/4" ID. After you’ve closed the head intake seacock in preparation to close up the boat, fill the sink with fresh clean water and flush the toilet. Because the seacock is closed, the toilet will draw the water out of the sink, rinsing the sea water out of the entire system. If your toilet is electric, be careful not to let it run dry…doing so can burn out the intake impeller. It will also be necessary to keep the sink plugged except when in use, either by installing a conveniently located shut-off valve in the drain hose or with a rubber sink plug. Otherwise the toilet will pull air through the sink, preventing it from priming. If the plumbing makes it impractical to tee the sink drain into the head intake hose, "plan B" is just about as simple: tee a new piece of hose into the head intake hose...add a shut-off valve (about $5.95 at any hardware store) and a gallon milk jug. After you've closed the head intake seacock, fill the milk jug with fresh water stick the hose into it, and flush the toilet. As for the CycleFlush...I'd never heard of it before, but after going to the same sites on the net that you prob'ly did, I wouldn't recommend it..for a couple of reasons: 1) It requires leaving the head intake seacock open while no one is aboard. That's dangerous...open seacocks and the #1 cause of boats sinking in their slips. 2) Just backflushing the head intake line doesn't rinse out the channel in the rim of the bowl or the pump...but it does continually introduce more sea water organisms into the line, some of which are large enough to get trapped and die in it, and can also contribute to sea water mineral buildup in the intake hose. 3) There's absolutely no need to repeatedly flush out the intake...all you have to do is flush all the the sea water out with a couple of quarts of clean fresh water once. So unless it has something to offer that isn't any of their specs--and for $125 including shipping, whatever it is would have to be really impressive--I wouldn't buy it, nor recommend that anyone do so.
