Crystallisation in Marine Toilets: Causes, Symptoms and Maintenance

If your boat or RV toilet is getting harder to flush, the pump sounds strained, or there’s a smell you can’t track down, there’s a good chance crystallisation is the culprit. It’s one of the most overlooked problems in marine and RV toilet systems, and it quietly gets worse and worse.

What is crystallisation?

When urine sits in a toilet system, minerals in it react with each other and with hard water to form a hard, white or brown scale. You may also hear it called urine scale, calcium build-up or struvite. It starts as a thin film and grows into a thick crust that can be as hard as concrete.

Where it builds up

Crystallisation forms anywhere urine and wastewater sit or splash, including:

the toilet bowl outlet and pump housing
joker valves, duck valves and other one-way valves
the inside of discharge hoses and pipework
tank-level sensors
the walls and roof of the holding tank.

Why it matters

Crystallisation narrows hoses, stops valves from sealing and makes pumps work harder. It also gives odour-causing bacteria a rough surface to live on, which is why a crusted-up system nearly always smells. Left alone, it leads to blockages, failed macerators and expensive hose replacement.

Dissolve it, don't just mask it

Many products on the market just cover the smell. ProPower Marine works differently. Its probiotic microbes break down the organic matter that binds the scale together, softening and helping manage deposits over time. At the same time, they take over the system from the odour-producing bacteria, so the smell goes with it.

How to use ProPower to treat crystallisation

Dose ProPower Marine through the toilet so it passes through the bowl, valves and pipework on its way to the tank.
Leave a small amount sitting in the toilet line when you leave the boat or van (about 20 mL in a glass of water, with a short flush).
For heavy build-up in the tank, fill it to the brim after dosing and leave it for a few weeks.

Regular use will help reduce further build-up, so your system stays free-flowing, odour-free and cheaper to maintain.

Shop and learn more: ProPower Marine Tank Treatment