The Multigrow controller is a modular system that can control the climate of up to 8 greenhouse/warehouse compartments in addition to managing other functions like fertigation, hydroponic dosing and environment monitoring; the best part is you only pay for the functions you will be using. You can receive alarms by SMS or email and the controller has remote access using a wi-fi tablet or smart phone. Although the climate control has a high level of functionality, many of the more complex settings are preset in the factory and you will get excellent results without changing these. They are provided for the perfectionists who would be frustrated if they were not available. Luckily, we provide "restore points" so if you change some advanced settings and don't get the results you expected it is simple to put the settings back to how they were.
The Multigrow is available in the following formats:
- A large touch screen format which is proving to be the most popular as it provides a larger, high resolution, high brightness full color touch interface. This is shown in the picture above.
- A screenless controller that is connected to a desktop LCD monitor, keyboard and mouse. This is a low cost option for situations that have a clean, office like environment in which to locate the MULTI. Alternatively, a wi-fi access point can be added to allow a tablet such as an iPad to be used as the user interface.
All of the above options can be connected to a computer network by ethernet cable or wi-fi and the controller can be accessed by any computer on the network that has a standard web browser. In larger installations it is convenient to set up an office computer with a number of screens (perhaps 3 or more) so that a different aspect can be displayed on each screen.
Any of the above options can interface with an iPad or Android Tablet device through the network connection and if the wi-fi is set up to provide coverage to the main areas of the farm this provides an extremely useful interface as the iPad can be carried around to where sensors etc are located to conveniently perform calibrations and settings changes.
Batch dosing refers to the situation where you have a large mixing tank to hold the irrigation water. The tank batch cycle involves filling the tank. stirring and dosing and then irrigating the crop as required by timer or solar radiation summer.
Systems like NFT and DFT do not require this batch processing as they are usually continuously recycled. The tank is continuously receiving drain water back from the crop and as the water level drops due to transpiration, a simple float valve opens to allow make-up water to enter. This may drop the EC a little and change the pH and so it is normal to have a simple on-demand hydroponic doser continuously monitoring the EC and pH and operating small pumps or gravity fed valves to add nutrient and/or pH stock solutions to correct the change.
The MULTI from Autogrow supports up to 8 batched or simple dosed tanks in any combination.
The doser will not adjust individual elements in the mixture and so it is possible for these to gradually get out of balance. In particular, elements like sodium which enter via the water will build up and may reach toxic levels. To avoid this the tank will need to be dumped periodically - hopefully, the grower will use the water for irrigating some outdoor crops rather than allowing it to pollute the environment. Commercial growers will take samples from their mix tank periodically (perhaps weekly) to send to a laboratory for analysis. This will avoid them wasting water and nutrient unnecessarily.
As the crop matures it is common for the recipe to change. The MULTI has the ability to dose up to 10 different stock solutions in varying ratio. For example, 100% A, plus 80% B, plus 60% C etc. These ratios are then easily changed so that the recipe always meets the needs of the crop.
When determining sizing of dosing pumps there are a few considerations.
- The nutrient stock solution is normally mixed to be approximately at a strength of 100:1. i.e. 1 part of A and one part of B will be diluted with 100 parts of water to give approximately the correct EC
- The large tank and grow benches will hold a lot of water. When filled with fresh water the initial dosing will be also very large but once dosed up the maintenance doser only has to top up nutrients etc as they are used by the crop. For this reason it is often arranged for the initial dose to be done manually and the dosing equipment is then only used to maintain the correct EC and pH. If this is done much smaller pumps and valves can be used for dosing.
- When dosing an empty tank, bear in mind that adding the nutrients to bring up the EC will have the side effect of lowering the pH. Be careful not to lower the pH too much before adding nutrients or you may find that the pH falls too low once the nutrients are added.
- If you install pumps that are too small they will have to do a lot of work and will wear out quickly.