This Water Chiller Kit includes S.S. 316 Coil, Flow Control Valve, and a Temperature Controller and Sensor. This Kit comes complete with all you see in the picture. This Water Chiller Kit will allow you to transfer the coolness from your supply coil to the warm reservoir. The controller will allow you to set the Maximum and Minimum. water temperature you desire in your system and then will only allow the cooling water to flow through the coil when the Controller finds the temperature outside of the operating range you have programmed into the Controller. Any temperature in hydroponics above 72F will promote disease and pests. Always look to your water temperature when root rot is present.
This kit uses water running through the coil to cool your reservoir, the water can be recycled or discarded depending on the setup of this kit.
The discarded method will increase your water usage on your bill and is best used in a non-metered environment.
The recycled method will need a way to transfer the heat from the water, we suggest running it though a radiator installed in your fresh air intake to cool of the water or any other form of heat transfer that will work in your situation.
Oxygen and Temperature effects - effective aeration
While forcing air bubbles deep down into the nutrient reservoir generally increases the dissolved oxygen levels in the nutrient, there is one other major factor to consider and that`s the temperature of the air being pumped into the nutrient. As the temperature of a nutrient solution increases, its ability to hold dissolved oxygen decreases. So a cool nutrient solution may in fact hold twice as much oxygen at `saturation levelí than a warm solution. For example a nutrient solution at 45 F can hold around 12ppm of dissolved oxygen at `saturationí, (meaning it is the most it can hold), but the same nutrient solution at a temperature of 85 F will hold less than 7ppm at saturation. This means at a solution temperature of 85F there is much less dissolved oxygen available for the plantís root system to take up. To complicate matters further, the requirement of the plantís root system for oxygen at warmer temperatures, is many times greater than at cooler temperatures due to the increased rate of root respiration. So warm nutrients mean a very high oxygen requirement from the plantís roots, but the nutrient can only hold very limited amounts of dissolved oxygen at saturation, no matter how much air is being bubbled into the solution.
Ideally, nutrient solution temperatures for most plants should be run lower than the overall air temperature - this has many beneficial effects on plant growth and development. However, if overly warm air from the growing environment is pumped into an otherwise cool nutrient solution, the warm air will rapidly increase the temperature of the nutrient to that of the growing environment. If air is being pumped via an air machine with an intake close to lights or other heat sources then rapid heating of the nutrient will occur. On the other hand, cool air has the ability to reduce the temperature of the nutrient if sufficient levels are pumped in and thus result in a much more highly oxygenated solution for the plantís roots. If keeping the nutrient solution temperature down seems to be a continual problem, checking the air inlet temperature of an air pump is a good idea.
Overly warm nutrient solutions (ideally nutrient solutions should remain below 80 - 85 F) for most warm season, high light plants and well below 75 F for cool season plants, can have serious effects on the plants root system. Apart from the increased oxygen requirement due to a much higher rate of root respiration which can rapidly result in oxygen starvation, high solution temperatures favour many of the root disease pathogens. Plant roots become highly `stressedí when experiencing high temperatures, particularly if there is a large mis-match between the air the root temperature. Root stress slows the development of new roots, resulting in reserves inside the root tissue being `burned upí during respiration faster than they are accumulated, and stress makes the root system in general more susceptible to disease attack. Keeping a check on nutrient temperature is vital, as is ensuring that air machines are not blasting hot air into the solution and cooking plant roots. Aeration is most effective when cool air is bubbled into a nutrient.
Oxygenation and nutrient uptake
Healthy roots supplied with sufficient oxygen are able to absorb nutrient ions selectively from the surrounding solution as required. The metabolic energy which is required to drive this nutrient uptake process is obtained from root respiration using oxygen. In fact there can be a net loss of nutrient ions from a plantís root system when suffering from a lack of oxygen (anaerobic conditions). Without sufficient oxygen in the root zone, plants are unable to take up mineral nutrients in the concentrations required for maximum growth and development. Maintain maximum levels of dissolved oxygen boosts nutrient uptake by ensuring healthy roots have the energy required to rapidly take up and transport water and mineral ions.
Calcium is one important nutrient ion which has been shown to benefit from high levels of oxygenation in the hydroponic nutrient solution Calcium, unlike the other major nutrients is absorbed mostly by the root growing tips (root apex). The root apex has a large energy requirement for new cell production and growth and is therefore vulnerable to oxygen stress If root tips begin to suffer from a lack of oxygen, a shortage of calcium in the shoot will occur. This shortage of calcium makes the development of calcium disorders such as tip burn and blossom end rot of fruit more likely and severe under oxygen starvation conditions. High levels of oxygenation ensure healthy root tips are able to take the levels of calcium required for new tissue growth and development.
While providing oxygenation with the use of air machines and stones is an excellent method of increasing the dissolved oxygen (DO) levels in a nutrient solution, the temperature of the air intake and nutrient solution must also be managed to ensure oxygen starvation in the root zone does not occur. Pumping hot air into a nutrient not only creates temperature stress in the root zone, it also results in less oxygen carrying capacity in the solution itself - a recipe for root suffocation that will rapidly affect the top portion of the plant as well. Getting oxygenation right means checking both aeration capacity of the equipment being chosen and temperatures in the nutrient and root zone.