Sludge is not an old wives tale but varies from area to area depending on how "hard" the water is. As for the question, no there is no real need to start over new as you can still clean out the tank. With that I will say that it would definitely be worth it if you have an inefficient unit (i.e. gas fired that is atmospherically vented, etc...) As for stirring the sediment up, it really depends on the system layout & how it is hooked up. I personally do not like systems that run back through the spigot
Replace water heater when installing hot water recirculating system?
Replace water heater when installing hot water recirculating system?Asked by Sam
I am about to have a passive with pump recirculating system installed. Would it be wise to replace my four year old 40 gallon tank just to start new? I have read elsewhere that recirculating systems may/might kick up the "yukky" sluge at tank bottom where the water will now be returned now, and circulate the crud, blocking shower heads and faucet and sprayers etc openings. AFAIK, tank never been drained via the tank spigot as recommended. Or is the sludge issue an old wives tale and can be disregarded for a four year old tank?