Wise decision...
The Monomatic has been out of production for nearly 20 years...no parts, or even the chemical for it, have been available for at least 15 years. Lord knows you don't want to replace it with another recirculating toilet...they STINK, and don't hold any more than the one you have. And while a 5-6 gallon "pumpable" portapotty is appropriate for sailboat up to 25-26', I don't think it is for a 30' sailboat...people just expect something a little better on larger boats. Depending upon your power resources, you have several excellent choices. If they're limited, you can't beat a PH II and holding tank...if they're plentiful, or you're willing to add to your batteries, you can enjoy the pushbutton convenience of a macerating electric toilet--in which case, the Raritan SeaEra would be the best choice. And if you'd like to avoid the hassle of maintaining a holding tank and pumpouts, now would be great time to add a Lectra/San--(CG Certified Type I MSD that treats waste and discharges it overboard). Spring is a couple of months away, so you don't have to make a decision immediately...check all of this out on the Raritan website (link below), ask more questions, and give it some thought before comitting to anything.
