I treated my 1400 gallon Switzer just to be safe. Chemical was around $500, but should never have to be touched again. I still send samples in every two years for piece of mind. A little bit of $ for a large investment. Don’t remember the treatment off hand. Went thru Wood boiler solutions llc.Just curious is anyone treats their water in a closed/pressurized system? 1000+gallons so traditional boiler treatments are normally sized for a 30 gallon system and would get very expensive for a system with 1000 gallons.