Spotless RV Tanks

Black and Grey tanks both get buildup. Grey tanks can give black tanks a run for the money when the bet is on "Which one smells worse?" - Let's look at how both tanks accumulate and then how we tackle the grime.

Grey Tanks: Soap scum, food particles, hair, fats, oil, dead skin cells, grease, and other residues can build up, leading to unpleasant odours and can disrupt the normal flow of water. In grey tanks, much of the waste floats on top of the water, leaving grease and other organics able to stick onto the sidewalls, coat pipes and leave remains in the gate valve. When gate valves start getting sticky, it can lead to unsanitary conditions.

Holding Tank Basics

Grey holding tanks are dark, damp, and filled with organic matter that settles at the bottom or sticks to the sides. Fats, oils, and grease can form balls and grow over time. Even those who thoroughly wipe down their dishes before washing still experience buildup. Leaving gate valves open worsens the situation, especially in summer heat, which can cause fats and grease to bake onto the tank sides. Bacterial slime can coat the pipes and cause sticky gate valves. Additionally, open holding tanks attract pests like drain flies, which can live in sewers or septic fields where you are visiting. It is recommended to keep grey tanks closed unless doing laundry.

Black Tanks: Hold onto to toilet water and everything that flushes down a toilet. The two bacteria types that break down waste in RV holding tanks are aerobic and anaerobic bacteria. Aerobic bacteria require oxygen to function, are fast-acting, and break down waste into carbon dioxide, water, and mineral salts. On the other hand, anaerobic bacteria thrive without oxygen, work more slowly, and produce gases like methane and hydrogen sulfide during the waste breakdown process. Both types are essential for efficient waste management in RV holding tanks.

Struvite: is a mineral crystal composed of magnesium, ammonia, and phosphate that forms in wastewater. It is a common issue in RV holding tanks, particularly black water tanks, due to the unique combination of chemicals and conditions present in these tanks.

Struvite buildup occurs when anaerobic (oxygen-free) conditions prevail in the tank, allowing ammonium and phosphate ions to combine and form a hard, crystalline scale. This scale can coat tank walls, valves, and piping, causing several problems:

• Clogging: Struvite buildup can block tank sensors, leading to inaccurate readings and potentially causing tanks to be emptied unnecessarily.

• Weight: As struvite accumulates, it adds significant weight to the tank, which can cause sagging and potentially lead to structural issues.

• Odors: Struvite can trap waste and bacteria, contributing to unpleasant odors emanating from the tank.

• Maintenance challenges: Struvite’s hard, concrete-like consistency makes it difficult to remove through regular dumping or tank rinsing. Specialized cleaning methods, such as hydro-jetting, are often necessary to break down and flush out struvite deposits.

  To prevent or mitigate struvite buildup, it is essential to maintain proper tank hygiene, including regular dumping, cleaning, and descaling. RV owners should also consider annual professional cleaning services to ensure thorough removal of struvite deposits.

Saftey Notice on Bleach & Black tanks.

The use of bleach in RV black tanks is strongly discouraged. Chlorine gas can be produced when bleach (sodium hypochlorite) reacts with ammonia, which is naturally found in urine and other waste materials. This reaction can create toxic chloramine gases and potentially harmful byproducts, making bleach an unsafe treatment for RV black tanks. Even small amounts of bleach can negatively impact the beneficial bacteria responsible for breaking down waste, not just your tanks but also the septic system you will be dumping into. Moreover, bleach can damage tank materials and potentially cause leaks or failures in the tank's sealing components.

Holding tanks may not be the stars of the show, but they play a critical backstage role in a well-operating system. From full-time living to on-the-road adventures, they are silent heroes for efficient waste management. Understanding their operation helps us appreciate their design and make informed decisions about their maintenance and use.

The difference between a black and grey holding tank isn't how they are manufactured and function, only by what materials they hold. The grey tank holds water from shower and sink drains, while the black tank holds sewer water from the toilet. Some RVs have a combination tank that holds shower, sink, and sewage water.

Holding tanks have only a few components: the inlet pipe for waste to enter and the outlet pipe with a gate valve for your regular dumping. The last component is the air vent to off-gas, preventing excessive pressure when holding and preventing vacuum suctioning that could cause tank damage or collapse when releasing tank contents.

The holding tanks are installed to release on the driver's side and are designed to operate based on gravity. When levelling your RV, note that the tanks have a gentle slope leading towards the drain. Solid waste settles at the bottom, while liquid waste floats to the top. This separation enables the tank to function without clogging and effectively manage waste.

Gate Valves: These valves control the flow of fluids in RVs. They are used in greywater and blackwater systems to keep fluids from being released and, when opened, fully release the contents from the tanks. Ensure the valve is fully open or closed for proper use to prevent leakage. Lubricate the valve stem with a suitable lubricant to ensure smooth operation.