Cleaning Marinas and Floating Docks

How To Clean Marinas and Floating Docks with Bio-Shield®

Including cleaning of:

  • Concrete Floating Docks
  • Wooden Floating Docks
  • Aluminium Floating Docks
  • Timber Jettys
  • Concrete Launch Ramps

Why choose Bio-Shield® for your Marina and Dock Cleaning?

Bio-Shield has been developed through 38 years of use in a demanding commercial environment and is proven to  work extremely well in Marinas and Docks.
Bio-Shield is a high quality product, and contains no bleach, acids, salts or phosphates.

The high concentration of active ingredients in Bio-Shield® when compared to other outdoor cleaners like Wet and Forget or 30 Seconds means it will cost less per diluted litre and cover more area at a lower cost.  Bio-Shield will not only clean concrete and timber surfaces, it will keep them clean longer than water blasting alone, with less damage, up to 97% less water use and at least half the cost.

Bio-Shield has very low toxicity and breaks down quickly into naturally occuring compounds with no genotoxic effects on marine species.

Should I water blast clean or use Bio-Shield?

Water blasting concrete to remove algae, moss and lichen growths will damage the surface by stripping away the cement and sand, leaving a rougher and more porous surface. 
Water blasting timber is even more destructive shredding the timber and leaving a furry finish.
Waterblast cleaning is a time consuming, expensive, and ultimately futile way to clean these surfaces: if they are not sterilized in conjunction with water blasting, the spores within the concrete and timber will quickly regrow and discolor the surface again.

The best method for cleaning and concrete and timber docks are exterior cleaning solutions like Bio-Shield.

A simple application will kill and remove the growths and keep the surface clean for extended periods. 
Regular lighter applications of Bio-Shield at the first sign of re-growths will effect a rapid clean up and keep the surface clean for an extended period. Reapplication schedule will depend on the micro climate around the treated surface - shaded areas may need  at least annual application, a drier, sunny and open area may only need 2 yearly applications.

DIY Application or use our Professional Application Service for your Marina and Dock Cleaning.

If you don't want to do DIY application we offer a professional Bio-Shield Application Service in Auckland or with our partner applicators around New Zealand
Prices are competitive - substantially less than the cost of water blasting. The benefits of using Bio-Shield is lower initial cost to clean and a treated surface will stay clean for longer than water blasting alone. Please contact us for a quote to supply  or to get in touch with a regional Bio-Shield Applicator near you.

Bio-Shield - Marina Dock with Moss and Black AlgaeConcrete Cleaning - Before
Bio-Shield - Marina Dock with Moss and Black Algae
Bio-Shield - Marina Dock Cleaned with Bio-Shield

Bio-Shield® Application Instructions

The concrete surface can be either dry or damp. Timber is better treated when dry to maximise absorption of the Bio-Shield by the algae growths.
All boats hulls, topsides, dock fittings and mooring ropes are unaffected by Bio-Shield - in fact Bio-Shield can be used directly on boats, sails and dodgers to clean them.

Check the weather forecast, or rain radar - brief showers after application on concrete will assist the action of Bio-Shield®
Air temperature above 10 degrees C° will help to accelerate bio-cidal action.

Keep children and pets off the treated surface until it dries. Do not feed pets on the treated surface until  the surface has been flushed by rain.

Premix the Bio-Shield® 1 part to 20 parts water in a pressure sprayer

Bio-Shield® Mixing Ratios - for a Pressure Sprayer

Clean WaterBio-Shield ConcentrateDiluted Bio-Shield
1 Litre50 ml1.05 Litres
10 Litres500 ml10.5 Litres
15 Litres750 ml15.75 Litres
20 Litres1 Litre21 Litres


If you have a respirator, now is the time to put it on, along with a pair of gloves and soft soled shoes and/or a pair of long pants. If you don't have a respirator, try to stay upwind during application. Evaporation of the solution on a warmer day will generate vapour that should be avoided where possible.

Application is best done on an overcast day at any time of the year, or early morning and late afternoon in summer if a warm sunny day is forecast. This slows evaporation and speeds the treatment process.

Start at the far end of the dock and work backwards towards the access ramp.
Ensure saturation of the concrete and timber.
Ensure the moss in any cracks or under the access ramps is soaked through to the base of the growth but try to avoid excessive overspray into the marina.

On any thick or large clumps of moss place the nozzle of the sprayer directly into the moss and inject it into the clump to ensure penetration to the deep roots and achieve a good kill.

On timber docks, use best practice for timber and apply a 2nd or 3rd lighter coat to ensure complete saturation so the  timber stays wet for 10 to 15 minutes.
On concrete there will be a dramatic colour change within minutes as the Bio-Shield starts to work. This colour change is temporary and will fade over 24 hours before the concrete begins to clean up.

Clean Up

Bio-Shield acts to kill the moss, algae on concrete over the next 2 to 3 hours. On timber, Bio-Shield will give an effective kill in 3 to 4 hours.

After a few days there will be visible color changes to the dead moss and lichen growths. Black algae does not change color. On concrete there will be visible signs of the clean up starting after a few weeks as the concrete begins to lighten up.

Full clean up on concrete can take from 3 to 6 months and 3 to 12 months on timber depending on the condition of the surface and the level of growths present.


It is best to reapply Bio-Shield® at the first signs of moss or green algae re-growth. 

On concrete and timber, this would mean reapplication of Bio-Shield every  2 to 3 years to keep the surface clean.
Moss may regrow annually in damp or shaded areas until the growth is under control with regular applications.
If the area is shaded and remains damp over winter then 6 monthly applications may be required.   On open and sunny areas the  application schedule can be up to 2 years.

Maintenance application will be easier, faster and use less diluted solution; any new growths will die off and the surface will clean up quickly, sometimes within days.
Once the surface is clean, Bio-Shield® will give optimal results with regular treatments.