Marine Holding Tank Treatment

The #1 treatment for smelly holding tanks

If you have sewage smells coming from your holding tanks or heads, or if your sensors are blocked, you need a solution, fast!

Noflex Digestor is a breakthrough treatment for holding tanks that will make you wish you discovered it earlier. It's the fastest, most cost effective way to eliminate smells, clean out the sludge in your tank and unblock pipes and sensors. 

Introducing Noflex Digestor

Septic tank treatment

How it works:

1: When Noflex granules are added to your tank they sink to the bottom where they react with the sludge, releasing bubbles of oxygen.
2: This disperses the sludge and releases proteins that are a source of food for the live ‘good’ bacteria in your tank.
3: These bacteria then eat the odour-causing sludge particles and you’re left with an smell-free holding tank!

Noflex Digestor is:

Fast - you’ll notice the difference within hours
Safe - it works by getting the good bacteria to eat the bad bacteria
Proven – it’s been used in commercial applications for years and is now available for septic, RV and marine use in Australia
Cost Effective – A pot of Noflex goes a long way. On average it lasts 3-4 months - that's around $3 per week

Buy now

Does your holding tank need treatment?

marine holding tank

Your holding tank needs treatment if:

-  Sewage smells are coming from your heads or plumbing
-  Your toilets are backing up or flow is slowing
-  Your tank is over flowing
-  Your sensors are blocked
-  There's sludge in your tanks that you can't get rid of

Why Noflex is the best holding tank treatment

-  It doesn't mask smells, it neutralises them
-  It activates the 'good' bacteria that eat the 'bad' bacteria
-  It gets rid of sludge and unblocks pipes
-  It's safe - the main by-product is sodium carbonate (washing soda)
-  It's cost effective - a single pot lasts 3-4 months

Buy now

How to use Noflex Digestor to treat your holding tanks


The tank MUST be vented to air. If there are vent filters they can be removed and bypassed as they will no longer be necessary (and are often more trouble than they are worth).

Avoid using the system during the initial part of this procedure.

Start with an empty tank. Pour about 4 Tablespoons (Tbsp) of Noflex down the external pump out line with 2 litres of fresh water. This should clean that line.

Then on EACH toilet (if there are more than 1) start the flushing pump to get a good flow of water into the holding tank. While flushing, pour 4 Tbsp Noflex into the bowl and continue to flush for 30 seconds. Let this sit for a day, then repeat on each toilet, but only use 2 Tbsp of Noflex.

Let this sit for approx. 8 hours, then start using the system again.

Pump out within 7 days (The sooner the better).

This procedure should have cleaned out the sludge in the pipes and tank and the odour should be gone. NB. If the tank was very badly contaminated, and the odour has permutated through the tank walls and the pipework, there will be residual odour in the bilges and any soft furnishings nearby. This odour could take some time to dissipate and bilges and affected areas need to be ventilated as often as possible.


After each pump out, add 2 Tbsp Noflex with about 10 litres water to the holding tank via a toilet bowl. Continue dosing at a rate of 1 teaspoon (tsp) per person per day. If
there is more than 1 toilet, alternate between them each day. As the system improves, this dosage may be reduced to about half of the above.

If there is odour from the tank vents during flushing, increase the dose a little. The product works best on a routine basis, rather than large doses.

If the boat is to be shut down for more than a week, add 1tsp for each 20 litres of effluent. Also put about 1/2tsp in each toilet bowl with water. This cleans the bowl and adds a shot of Noflex to the tank when you come back and start up.

Other Products For Marine Tanks

Zwitterionic Laundry Detergent

Non-foaming, bio-degradeable laundry detergent.

More info

Zaal Toilet Bowl Cleaner

Non-foaming, scale-removing cleaner designed for marine systems.

More info

Sea Solve Salt Remover

Non-toxic, bio-degradeable salt remover safe for all surfaces.

More info

Satisfaction guaranteed. 100% refund if you're not happy with our products or service.

We accept:

Payment methodsPayment methodsPayment methodsPayment methods