How can I solve Holding Tank Odours?
Should you have an odour problem from a holding tank vent, you should look at ways of increasing the ventilation to the tank. Holding tank odours are caused by anaerobic bacteria and increasing ventilation will allow aerobic bacteria to regain control and odours will rapidly reduce and stop altogether.
Check there are no air leaks in the vent hose or the access panel on top of the tank and also try installing a larger air vent and/or another vent hose on the other side of the holding tank and connecting it to a fitting on the other side of the hull. This will get a good cross flow of air in the tank and will certainly solve the problem. Expensive carbon filters or Sulphur Dioxide filters just restrict the air flow and can aggravate the problem, it’s best to remove them.