TEFLON TAPE. Brand spanking new rig. No line no waiting. Get it home, out comes the plug, on goes the teflon tape. I use good old Mexican grain vinegar to acidify the tank. Sixteen cups into a 10 gallon tank. Light a fire under it. Set thermostat on max high. Leave hot vinegar and water for 48 hours. Drain but do not flush. Mix one pound of baking soda into water and inject into heater. Leave heat on max for 24 hours ... "Ewwww!!
I have tried all manner of tank cleaning and this one makes a mockery out of the other cleaning attempts. when it is finished, the inside is taken down to bare shiny aluminum or glass, whatever the case. if the tank uses a magnesium sacrifice, replace with a standard PLASTIC plug for the cleaning.
Folks have recovered as much as FOUR FULL CUPS of buildup using vinegar and baking soda. It is USELESS to use vinegar alone. The neutralizer is vital to REMOVE sediment.