How to Dose Solbio and Prepare Your Toilet Cassette Properly

If you want the best performance from Solbio Original, getting the dosing right and preparing your cassette correctly—especially when switching from traditional chemicals—makes a real difference.

This guide keeps it simple and practical, and also shows you a few additional ways to get even more value from the product.

Getting the Dose Right

A standard dose of Solbio is 40ml, and this should always be used with at least 1 litre of water. The water is important as it ensures the base of the cassette is fully covered, allowing the product to work effectively across the entire surface rather than sitting in one concentrated area.

There are a few easy ways to measure 40ml:

• Use the dispensing tap – hold it open for around 2 seconds

• Use a measuring cup if you prefer accuracy

• Decant into a smaller bottle for trips away

The last option is often the most convenient. For example, if you take a 120ml bottle, you know that roughly one third of the bottle equals one dose.

This means:

• You don’t need to carry the full container

• It saves weight and space in your caravan or motorhome

• It’s quicker and easier when emptying and recharging the cassette on site

If you’re travelling in a hot climate, it’s better to add more water, not more product. Higher temperatures increase evaporation and can concentrate the contents of the cassette. Adding extra water helps maintain the right conditions inside the tank and keeps everything working as it should. Increasing the amount of product won’t improve performance in these conditions.

Why Preparation Matters (When Switching to Solbio)

If you’re moving over from a traditional toilet chemical, there’s one step you shouldn’t skip.

Most conventional products contain antimicrobials designed to kill bacteria (which isn't great - read about that here). The problem is, those same chemicals can remain in your cassette and continue to suppress the natural bacterial activity that Solbio relies on to work effectively.

If you don’t remove those residues, you may not get the performance you expect.

The good news: you only need to do this once when you switch.

How to Prepare Your Cassette for Solbio

Think of this as a proper reset of your cassette.

Step-by-step:

1. Thoroughly clean the cassette

   • Empty it fully

   • Rinse well

   • Give it a proper scrub, just like you would at the end of the season

2. Fill with fresh water

3. Add 40ml of Solbio

4. Close and shake the cassette

   • Make sure the solution coats all internal surfaces

5. Leave for at least 24 hours

   • Rotate the cassette onto different sides during this time

6. Empty and rinse again

After this, your cassette is ready to go.

Ongoing Use

Once you’ve done the initial clean:

• Add 40ml of Solbio along with at least 1 litre of water after each empty

• Ensure the liquid covers the base of the cassette before use

• In hotter conditions, increase the amount of water, not the dose

• No need to repeat the deep cleaning process

• Avoid using antibacterial cleaners inside the cassette, as these can interfere with performance

Other Ways to Use Solbio

Solbio isn’t just for the toilet cassette. It can also help keep other parts of your caravan or motorhome fresh and clean.

Flush Water Tank

Some caravans have a separate flush water tank that feeds only the toilet.

• Add 20ml of Solbio each time you fill the flush tank

• This helps keep the tank clean

• It also gives a fresh smell with every flush

Grey Tank (Waste Water Tank)

Grey tanks can develop unpleasant smells over time, often caused by food residue and build-up inside the tank and pipework.

Solbio can help manage this in two ways:

Quick / On-the-Road Treatment

• Pour 40ml of Solbio down each plug hole (e.g. kitchen sink, bathroom sink, shower)

• Wash down with around 1 litre of water per drain

This helps:

• Freshen the tank

• Clean the pipework

• Keep things under control while travelling

Deep Clean

For a more thorough clean:

1. Empty the grey tank fully

2. Close the outlet valve

3. Pour 100ml of Solbio down each plug hole

4. Run taps until the grey tank is completely full

5. Go for a short drive to agitate the contents

6. Leave for at least 24 hours

7. Empty the tank

Toilet Bowl Cleaner Spray

Solbio can also be turned into a simple, effective toilet cleaner:

• Add 40ml of Solbio to a spray bottle

• Top up with water

This gives you a ready-to-use cleaning spray for the toilet bowl that works in harmony with the rest of your system.

Final Thought

Solbio works with natural processes already happening in your cassette and waste systems. Give it the right conditions at the start, and it will do the rest—keeping things fresh, clean, and working as they should.