Home E Support Overview E AST FIT™ Systems Resources AST FIT™ Systems Resources Our FIT systems are integrated units that consist of a tank and built-in filter. No plumbing or setup needed. FIT 800 BrochureFIT 400 BrochureAST FIT System Manual View HereConfiguration Instructions View HereInstallation Assembly View HereOperation & Backwash View HereSpecifications & Sizing View HereFAQ & Troubleshooting View Here