Pretreatment septic tank systems.
In the effort to reduce sludge levels and prevent clogging in the leach field, many septic tanks have pre and post tank treatment systems. The pretreatment system is generally a separate tank with a filter before the primary septic tank. The idea is to keep the sludge level in the primary tank lower. It is a good system in that it increases capacity of the system and allows for longer periods of time between pump outs, but it usually does not do anything uniquely different than the single tank system. These types of systems must be inspected using the same method described in our FAQ how to inspect a septic tank and what to look for.
TankTechsRx for Septic Systems will work the same way with a pretreatment system it does in the typical single tank. Just add one liter once a year in the typical tank by flushing down the toilet assuming the total volume of both tanks is less than 1500 gallons. Over 1500 gallons or a tank with heavy sludge would require 2 liters the first year, then one liter per year thereafter. The mother culture will grow in the pretreatment tank and then drain into the main tank where it will continue to grow consuming the sludge in both tanks. From there it will pass into the drain field keeping the entire system healthy.