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Trouble Shooting The Under Current

By cch20  

Have troubleshooting questions about your Under Current system? Below you will find the most common issues growers may have when growing in the Under Current. Issues touched upon include pH instability, root health, leaf and stem growth and finally system issues. You will find the cause and effect for each issue, along with treatment regimens and preventive maintenance.

Ph Instability:

Potential Hydrogen (pH) is the measurement of acidity or alkalinity of a substance. In a controlled growing environment, the range of pH made available to a plant is completely controlled by the grower. The range of pH regulates the ability of plants to absorb the essential elements required for successful growth and production. Unstable pH levels and instability can cause issues that will affect plant growth. It is important to have correct, stable pH levels throughout the life cycle of the plant to prevent any nutrient deficiencies that can derail a successful harvest. It is recommended a pH range of 5.5 – 6.5 is maintained for optimum nutrient uptake.

Nutrient Quality:

Nutrient quality is an important factor in successful plant cultivation. In relation to pH, the quality of nutrients used has a direct effect on the (in)stability of pH levels. This interaction between water, nutrients and root structure will begin to change the chemical compounds of the solution. As this natural process occurs it will cause pH levels to stabilize if quality nutrients are utilized. Low quality nutrients will become unstable during this process, in effect causing pH levels to swing. It is recommended that high quality nutrients be used in all growing techniques. Our Cultured Solutions line of premium hydroponic nutrients are recommended as a quality nutrient choice for all growing applications. Cultured Solutions provides the cleanest, pH stable, highly soluble nutrients available to growers.

Water Quality:

Excellent water quality is needed for all growing techniques; this is especially true in hydroponic cultivation. Although convenient, the utilization of treated municipal waters can become an issue for many gardens. These waters contain added chemicals and minerals that are not beneficial to plants. It is recommended that filtered or reverse osmosis (RO) water is used in hydroponic applications.

Root Health:

Another factor that must be addressed when discussing pH (in)stability is root health. Bacteria that cause unhealthy roots can excrete bio matter that will cause pH level swings. A good indicator of bacterial disease is if pH fluctuations occur right after adjusting the solution. The interaction between bacteria and solution can change the water chemistry causing pH instability. It is suggested that you run a sterile system; utilizing clean, cool, moving water. A benefit of growing in the Under Current is the ability to keep water cool and moving. These functions can potentially keep dangerous pathogens at bay and limit pH instability.


Roots Issues:

Healthy roots are a must for a successful hydroponic grow. Roots are the way by which nutrients, water and oxygen are absorbed for use throughout the plant. Look for roots that are firm, white, free of debris and discoloration. The root mass should be dense and fresh smelling, with a combination of fine and coarse roots spreading throughout the root structure. When dealing with any type of bacterial or nutrient issues, it is the roots that often are the first to show signs of stress. Issues that can affect roots range from dangerous pathogens, decaying roots and the use of low quality nutrients. It is important that any issues that arise be taken care of quickly with an effective treatment regimen.

Brown and Slimy Roots: 

Brown or discolored roots often are the telltale sign of root rot. This root infection is caused by several species of fungal organisms called Pythium that make their home within the root system. Pythium thrives under conditions such as low aeration, poor drainage and high water temperatures above 72 degrees. Other issues that can cause brown roots is using low quality nutrients that can stain the root structure. These nutrients contain dyes and other chemicals not conducive for a healthy root structure.

  • In the case of “root rot”, it is recommended that an entire nutrient solution change out and flush is performed. Flush the system with a quality root zone optimizer, such as UC Roots. This is a safe effective treatment for infected roots that can be used throughout the life cycle of the plant. Any dead, decaying roots should be removed from the root structure and all equipment disinfected. Run the system 1-3 days at the rate of 5-10 mils per gallon of UC Roots until symptoms cease. Then slowly reintroduce nutrient solution at low rate.


Leaf Issues:

Throughout the course of a plants life cycle they may experience issues that can leave growers scrambling for solutions. Often these issues are noticed first amongst stem and leaf tissue. Plant leaves may be the first to show symptoms because of their delicate nature and their role in the photosynthesis process. The first step in treating any leaf issues is first determining the source of the problem, then taking the correct actions to fix and prevent the problem from reoccurring.

Clawing and Canoeing: 

Plants that are experiencing “the claw” or canoeing are often affected by improper pH levels and/or nitrogen toxicity. Nitrogen toxicity is the most common cause of this claw effect. Leaves will begin to droop downwards and cup into themselves. Theses affected leaves will eventually turn yellow, brown and fall off. Unlike nitrogen deficiency where lower leaf structure is the first to show signs, nitrogen toxicity will affect the entire plant. A key sign to look for is while affected leaves are clawing and turning yellow, the rest of the plant will be dark green. Often nitrogen toxicity is caused by growers supplying additional nitrogen to a plants diet.

  • To treat nitrogen toxicity growers should reduce nutrient strength by 25-50% and cease any additional nitrogen based supplements. Use a quality nutrient line such as our Cultured Solutions Veg A & B, which combines to provide all the macro and micro nutrients needed for lush vegetative growth


Yellowing of leaves is often attributed to nitrogen deficiency in non-hydroponic applications. This occurs when nitrogen is lacking in plant nutrition, often in the vegetative stages of growth. Older, lower leaves are the first to yellow, as the plant pulls nitrogen from this lower growth to provide for new growth at the top of the canopy.

However, yellowing of leaves in the Under Current system can have its cause from feeding high levels of nutrients.  These high nutrient levels will induce nutrient lockout. This is caused by the buildup of salts from excess nutrients. This buildup of salts over time will cause the nutrients to become unavailable to plants, preventing the plant from accessing the nutrition needed for healthy growth. As this lockout takes place the plant will pull the nutrition needed from its leaves, causing the yellowing effect most often associated with a nitrogen deficiency.

  • The first step to treating the yellowing of leaves caused by nutrient lockout is to add fresh, clean RO water (pH 5.9-6.0) to the system and top-off reservoir. Add this fresh water at a rate that will reduce PPM by 5%; continue this treatment for 7 days until symptoms cease. If after a week there is no improvement in plant health it is recommend to perform a system flush. To perform a flush, drain the entire system, fill up with fresh, clean RO water (pH 5.9-6.0) and add UC Roots at a rate of 10 mls per gallon of water for 24 hours. Monitor plants closely and only once symptoms cease should nutrients be reintroduced slowly.

Wilt / Dull / Dehydrated:

Any symptoms such as wilting, dull, or dehydrated leaves is usually attributed to a nutrient toxicity or nutrient burn. Nutrient toxicity is caused by feeding too high of levels of nutrients; essentially more food than your plants can utilize. Leaves become off colored and brittle starting with tips and edges, as symptoms progress the entire leaf structure will be affected and eventually die off. The main concern with nutrient toxicity is loss of leaf mass, as severely affected leaves rarely recover.

  • It is recommended to perform a nutrient change out and reduce nutrient strength my 25-50%. Utilizing a nutrient meter such as a Bluelab PPM/TDS meter will ensure correct nutrient strength and prevent any further issues. Only once symptoms cease should nutrient strength increase at a slow rate.


System Issues:

The Under Current system was built to perform, as such the necessary steps must be taken to ensure that it can operate at peak performance. Some of the most common system issues growers may have are leaks and water pump issues. When setting up your Under Current system, take the time to ensure all fittings are seated correctly and securely installed. Follow all directions and contact tech support with any issues.

System Leaks: 

Hydroponic systems can be susceptible to leaks, this is often attributed to user error or a faulty part.

  • Bulkhead Gasket Leaking:

    1. Problem: Gasket is not seated properly before installation
    2. Fix: Remove bulkhead gasket and inspect for any damage. If no damage, reseat gasket until flush against bulkhead lip and reinstall. If problem persists, contact tech support.
  • Damaged Part:

    1. Problem: Cracked manifold damaged during shipping or installation.
    2. Fix: Contact customer support to order a replacement.

Pump Issues:

Pump issues can be complex, but there is usually a fix for each problem.

  • Lacking Pressure:

    1. Problem:Lack of prime
    2. Fix: Pump must be primed. Turn off pump, close the return manifold valve and raise the water in the complete system above the water pump. Release water by opening valve. Pressure and circulation will be restored. If there are still issues, contact tech support.
  • Leaking:

    1. Problem: Cracked fitting can be the result from over tightening fittings. Female fittings can crack under too much pressure, be sure to hand tighten all pump fittings.
    2. Fix: Contact tech support to order replacement pump parts.
  • Faulty Impeller:

    1. Problem: Pump making “clacking” sound and will not pump solution.
    2. Fix: Contact tech support to order replacement impeller.