When using open hydroponic systems to grow your vegetables, algae will grow, in fact it thrives, where sunlight is available to exposed open water.
Algae becomes a nuisance in high quantities as it reduces the available oxygen in the water as well as utilizing the nutrients in the solution. This will affect the growth of your other plants.
It is also unsightly.
This instructable shows a mechanical, cost effective, solution to combat algae growth in my system.
Step 1: Realising That Your Algae Is a Problem
Once the plants are removed, the actual amount of algae in the system is revealed.
One method is to use hydrogen pyroxide as a chemical solution to combat the algae growth.
Another method, which I will be using, is to prevent light from gaining access to the open water through covering the nutrient tray.
Step 2: Choosing the Type of Covering for the Nutrient Tray
250 Micron plastic is to be used.
The reason for the thickness of the plastic, is that the sun's UV rays aren't able to penetrate through.
It is easy to work with, (not too flimsy).
And I also had part of a roll in stock, (LOL).
The reasoning behind using the plastic is to create a dark environment underneath, which will stop the algae from receiving sunlight, which will prevent it from growing and cause it to die off.
Step 3: Cutting the Plastic and Attaching It to the Nutrient Tray
The plastic sheet is cut slightly larger than the nutrient tray on all sides.
This is to allow for the plastic to be clipped onto the nutrient tray.
2 Methods were used to attach the plastic.
1. A piece of 20mm diameter polyprop pipe was used initially. Each piece is approximatly 15cm long. The pipe was cut, using a carpet knife, through the length. The plastic was placed over the nutrient tray and the pipe was used to as a clip to attach the plastic to the nutrient tray.
2. Page binder sliders were used as the next option to attach the plastic and tray together. This became the preferred method.
Once the plastic was attached to the nutrient tray, X cut's were made over the openings of the pot holder trays and the pots inserted into the available openings.
Step 4: The Final Look
The nutrient tray has been completly covered with the plastic over the open water sections and the binder sliders used as the preferred attachement method.
The only open sections are where the plants have been planted in the system as well as the inlet area for the nutrient solution.
Step 5: Does It Work
The idea that algae will not grow without available sunlight is now to be tested.
The first picture shows the algae before covering, the second picture show the amount of algae after the system has been covered for 5 days.
YES it works. There is a marked reduction of alge in the covered system verses the uncovered system.
Step 6: Comparisons
The first picture show the algae in the uncovered tray.
The second picture shows the reduced algae in the covered tray
Step 7: Final Comparison.
The proof is in the pictures.
The pictures shows the comparison between the uncovered and the covered trays only after just 5 days.
This method shows how one can slow down and even prevent algae growing in your open hydroponic systems with an easy and inexpensive solution.
I hope this instructable is helpful.