What is the cost of biofilm to your business?

Posted on 02 Sep 2016 by Valerie




What is the cost of biofilm to your business?

Biofilms, the slimy residue that lines your irrigation lines and blocks drippers, are a serious issue that affects every nursery and grower. You probably haven’t thought about it much more than annoyance over a blocked line but biofilms cause more trouble than this.

Destruction of biofilms is critical in plant pathogen prevention. Biofilms are the home for bacteria, fungi and viruses who are protected by the cellular matrix of the film preventing most disinfectants and medications from working. Disease is directly related to biofilms even for humans: 65% of human microbial disease are the result of biofilms.

Block drippers, valves, sprayers, filters and other parts of your watering equipment. All of which take time to clean and re-assemble. And this isn’t a solution but ongoing time requirement to solve symptoms of the underlying problem of untreated biofilms.

Lack of consistent watering with sprayers no longer having the same coverage if they work at all. Drippers blocked which you may or may not recognise by the stress to your expensive advanced plants before it is too late.

How much does not thinking about biofilms hurt your plants and wallet? Well let’s do some math-

Say you’re a medium grower who specialises in a variety of plants including some advanced trees, and you put a value on your time of $30/h.


4 sprayers get blocked every week taking 10 min to clear each one = -$20.00/week

5 drippers get blocked every week taking 10 min to clear each one = -$25.00/week

Plants aren’t being watered

Half the plants under a sprayer are stressed and stunted from lack of watering = $200 month

2 of the blocked drippers went unnoticed and stunted the tree. You can’t sell it until it recovers next season $200/month

Two of those blocked drippers killed a sensitive tree on a hot day = - $400.00/month in summer


Having losses of one tray tube stock from regular disease issues= -$100/ month

Say you lose two medium plant a week randomly in your nursery -$50 /month

Say you lose one advanced tree every other month - $200 every two months.

Total= Loss of $10570 every year. Some of these numbers may be higher or lower in your nursery, we have based this on information provided to us from the experiences of nurseries around Victoria. I encourage you to do the math for your business and see what biofilms are costing you.

Cost to solve = $0.69 per 10 000 of water using Vibrex and a CDLa dosing unit.

Biofilms? What are they?

Ok, so I understand now that biofilms are an issue but what actually are they?

Put most simply, it is the films and clumps of slimy material that grow and line every pipe that is exposed to water. The slimy material is a defence response by massive colonies of various types microorganisms that are well protected within the biofilm layer. If you look down a sprayer line or any pipe exposed to water you will be able to see the brown to green slippery layer that coats the pipe interior.

All nurseries have biofilms and even though you do not recognise them as an issue it is likely you have been experience some or all of the symptoms. All water coated surfaces have biofilms, but the warm, high surface area, exposure to surrounds through pipe outlets and high volumes of untreated flow water that nurseries feature is very conducive to excess biofilm production. Even buried, painted or black poly do not prevent biofilms, it just causes growth of non-photosynthetic microbes and films.

Some of the symptoms of biofilms:

Consistently blocked drippers and sprayers leading to plant stress or losses

Time spent clearing drippers and sprayers

Green to brown gunk blocking filters and other pieces of equipment

Disease outbreaks

Battling with algae that grows tougher and tougher

Lowered plant survival or consumer complaints from early plant death

Many of the microbes that live in biofilm do not directly harm the plant (except for when they stop the water supply) however many of the occasional and chronic disease outbreaks will be the result of pathogens living in this very same layer.

Some of the pathogens that live in this layer include:







Plus a whole host of various harmful bacteria, viruses, protozoa, algae (and algal toxins), fungi and invertebrates.

Biofilms are the home of disease causing microbes. Within this layer they are well protected from many chemicals and agents. They grow and multiply seeding your irrigation water with a constant flow of disease conveniently directed to their new plant hosts. This leads to plant losses, stress and shrinkages that all hurt your wallet.

They only effective way to combat biofilms is with an effective disinfectant such as chlorine dioxide.

Is biofilm costing you money in labour, killed or stressed plants from lack of water or disease? The answer is yes and it is cost effective to solve with chlorine dioxide!


5 stages of biofilm development. As shown at stage 5, water is seeded with microorganisms from the biofilm layer. Taken from: Looking for Chinks in the Armor of Bacterial Biofilms Monroe D PLoS Biology Vol. 5, No. 11, e307 doi:10.1371/journal.pbio.0050307

How to remove and prevent biofilms?

Biofilms are one of the ultimate strategies employed by microorganisms to defend themselves from attack while they grow, multiply and spread. Pathogens, such as plant diseases like Pythium, can continually seed irrigation water with disease while being protected from treatments hiding within the depths of the biofilm.

Biofilm is not readily removed by many of the treatments that are used by nurseries. Flushes with extreme doses of chemicals can be used to remove existing biofilms but at the end of the treatment they will take hold of the pipe surfaces and begin settlement of your pipelines within seconds to minutes. Lower doses of most acids, chlorine and peroxide treatments cannot remove biofilms. Using ineffective treatments such as hypochlorite may attack the surface layers but they cannot penetrate and truly work on the biofilm itself; in fact, such treatments can cause an increase in biofilm growth as they bounce back.

The only way to truly combat biofilms is sustained low doses of an effective disinfectant like chlorine dioxide.

What makes chlorine dioxide special in comparison to the other disinfectants?

It’s a gas dissolved in water. This is a special property that makes it highly effective at tackling biofilms. Gases pass more easily through boundaries than liquids meaning the chlorine dioxide can get down to the pipe surface even when covered by biofilms, killing the microbes along the way and detaching them from the surface.

It’s an extremely strong disinfectant. Generally regarded as being 3 to 5 times stronger than regular chlorine it can readily kill organisms that many other disinfectants cannot.

While a strong disinfectant it has a lower oxidation strength but has a higher oxidative capacity- which in English means it isn’t wasted on tough organics like dirt but more readily and aggressively attacks weak organics like microbes.

Not dependent on water chemistry. You do not have to be concerned with water pH for disinfection as it is effective over any pH you would provide to your plants.

Cheap for sustained low concentration dosing. All it takes is maintaining a residual of 0.25 to 0.3 ppm to ensure biofilms are being removed and prevented from forming.

Comparison of Vibrex chlorine dioxide treatment before and after a sustained treatment. Pipe surface has been completely cleared of biofilm.

Regen Ventura- Affordable Chlorine Dioxide Dosing Equipment

So why doesn’t everyone use chlorine dioxide in their nursery water treatment?

It, like everything, comes down to cost.

Chlorine dioxide being a gas dissolved in water makes it highly effective for water treatment but because it is a gas it cannot be easily stored or sold as-is and therefore must be generated on site. This results in a higher equipment price than other disinfectant dosing units as you require reaction cells and two dosing pumps. Those who want the highest performance from their watering and can see the costs of biofilm and pathogens to their business have made decisions to make this investment as the payback exceed costs. But not everyone has the money to invest- there is always another dam to dig or equipment to buy.

We here at Grayson Australia understand this have challenged ourselves to develop a simple and affordable chlorine dioxide dosing system available to smaller nursery applications that does not compromise on quality. Our solution is Regen Ventura.

Regen Ventura make this cost reduction possible in two ways:

Non-dangerous chemicals are added to the storage vessel as an easy 1:1 2-part mix. The remainder of the container is filled with water. The chemicals have been designed to be safe to use and produce a dissolved chlorine dioxide mixture that has stability for up to a month.

A high quality venturi injector is implemented to dose chemicals easily using only the pressure of your pipe line. No electrical inputs are required.

Dosing is controlled by using the high quality tested valves to adjust flow and pressure across the injector and features both a coarse and fine adjustments on dosing line. The injector used is Mazzei injector who are renowned for producing high quality products. All adjustments can be measured using the included flowmeter which features durable 316 stainless steel fittings. A helpful guide will run through the DIY installation, best arrangement for you, and how to setup and run the system.

Included in the package is a high quality test kit, test tablets, dosing unit, chemical mix tank and the chemicals meaning you can be sure what you need to get started with your chlorine dioxide dosing. You could be eliminating all of your biofilm issues

with Regen Ventura for only $1498 +GST.

Call us today to discuss how we can end your biofilm troubles!

Ph: 03 8727 6900