I have cleaned my unit but the red light stays on

Likely so these units usually put out ozone into the air in your home which is a known lung irritant. If you truly have indoor air quality issues the only way to properly attack it is through three steps
source control - what's causing it(uv lights to kill it usually)
ventilation - bring in fresh outdoor air and exhaust stale indoor air(ERVs and HRVs depending on your climate some dealers won't sell these if they don't offer it to you they are dumb find someone who does they are Recovery Ventilators)
filtration - a whole home filtration system (look to dealers who carry Lennox who is the only company with a 100% ozone free product line and the highest filtration rates available on the market "MERV 16" filters or Trane is ok as well as Carrier systems)