Most of the precipitated iron either sticks to the sides of the tank or stays in suspension and goes to the iron filter where the media removes it. Anytime I manually flush the contact tank, it runs clear within seconds.
My Banjo filter traps about a teaspoon of sand in a month so flushing it once a quarter works for me.
I have my iron filter programmed to backwash 3 times a week. Once a quarter, I also do a few back-to-back manual backwashes at higher pressure. I open up the micronizer bypass for more GPM and jack the pressure to 80 PSI.
I've been wondering about this for years; this is the first definitive answer I've gotten. Good (I guess) to know that it's normal. I use a simple spun filter following the 120-gallon contact tank, and it has to be changed every 2 or 3 months. I wonder if the swirly contact tanks (http://www.apwinc.com/retention_tank.html) have the same problem? I may know in a few weeks.
Originally Posted by LLigetfa
LLigetfa, what kind of filter are you using? Backwashing three times a week seems like a lot? I was hoping to only backwash twice weekly at most. What have you done to determine needing the three times weekly? Do you have anything after the iron filter? One more question what are you using for on oxidizer?
Mikey, what is the price of that contact tank?
Don't know; mine came as part of a system. Call the vendor -- under "Contact Us" on the page I linked.
Originally Posted by statin