How do you oxigenate your reservoir?

[Dr.Dutch]

Using air pumps and bubblers to oxygenate a reservoir for the roots/plants is completely unnecessary and bro-science when growing in coco substrate. Coco coir naturally contains a lot of air, providing ample oxygen to the roots. This practice is only relevant in water-based systems like Deep Water Culture (DWC), where maintaining dissolved oxygen levels in the water is crucial.
Water circulation in your reservoir for coco is only necessary to prevent the water from becoming anaerobic.

PS:
And please leave the H2O2 out of your nutrient solution. At that concentration, it does absolutely nothing against fungi or bacteria. Instead, it reacts with the chelates, potentially causing some micronutrients to precipitate out, and it disappears from the nutrient solution in a very short time. See also

From these choices, both hypochlorite and hydrogen peroxide have poor disinfection performance at the concentrations tolerated by plants and are hard to maintain at the desired concentrations through an entire crop cycle without ill effects

Disinfection of nutrient solutions in recirculating hydroponic systems – Science in Hydroponics

scienceinhydroponics.com

Healthy roots minimally leach nutrients into solution [101]. In our experience, increased turbidity usually indicates unhealthy roots with carbohydrate leakage. We have found that the solution in well-aerated DWC remains clear throughout the crop cycle (months) indicating low microbial activity in the bulk solution.
Several water treatment technologies have been used to reduce disease. These include chlorination, hydrogen peroxide, filtration, and ozonation [102,103,104,105]. Some sanitizers can degrade chelates in solution [106]. Ultraviolet light has been used in recirculating systems to reduce microbial activity in solution and to help prevent disease [107], but UV photons break down chelates [108], and the chelates must be re-added. Acidic root zone conditions have also been shown to reduce disease persistence [109,110].
We have not found any of the above treatments necessary. Root-zone disease has been minimal in our systems, perhaps because the root surfaces are uniformly well aerated and the steady-state nutrient levels that come from the daily refill solution result in healthier roots.

Principles of Nutrient and Water Management for Indoor Agriculture

Mass balance principles are a cornerstone of efficient fertilizer use and can be utilized to optimize plant nutrition without discarding or leaching solution. Here, we describe the maintenance of closed hydroponic and soilless substrate systems based on mass balance. Water removed by...

www.mdpi.com

 

[Dr.Dutch]

Correction and clarification on the H2O2 point – conclusion still stands: It has no place in nutrient solution.

The Impact of Adding H₂O₂ to a Plant Nutrient Solution Containing EDTA​

Adding hydrogen peroxide (H₂O₂) to a nutrient solution with EDTA affects the chemical stability, micronutrient availability, and plant growth in several ways:

1. Oxidation of the Iron Complex (Fe-EDTA):
   • Iron is often supplied as Fe-EDTA to remain soluble and plant-available.
   • H₂O₂ oxidizes Fe²⁺ in the complex to Fe³⁺:
     
     
   • Fe³⁺ is less available to plants than Fe²⁺ due to its reduced cellular uptake.
   • Further reactions may destabilize the Fe-EDTA complex, leading to iron precipitation (e.g., as Fe(OH)₃), reducing iron availability.
2. Radical Formation and Oxidative Stress:
   • The Fenton reaction between Fe²⁺ and H₂O₂ generates hydroxyl radicals (HO⋅HO^\cdot), which can:
     • Degrade EDTA, compromising its chelating ability.
     • Oxidize other micronutrients like manganese (Mn), copper (Cu), or zinc (Zn), altering their availability.
     • Oxidize organic substances, such as amino acids or humic substances, reducing their efficacy.
3. Antimicrobial Effects of H₂O₂:
   • H₂O₂ acts as a disinfectant, reducing harmful pathogens like fungi or bacteria in the nutrient solution.
   • However, this antimicrobial effect is limited at low concentrations tolerable for plants and diminishes quickly as H₂O₂ decomposes.
   • High concentrations may harm beneficial microbes, such as Rhizobium or Bacillus spp., disrupting symbiotic processes crucial for nutrient cycling.
4. pH Alterations:
   • The reaction of H₂O₂ with Fe-EDTA produces hydroxide ions (OH−OH^-), increasing the pH of the solution.
   • A higher pH can further reduce the availability of micronutrients like iron, manganese, and zinc, as they tend to precipitate under alkaline conditions.

Effects of Hydrogen Peroxide Products on Basil, Lettuce, and Algae in an Ebb and Flow Hydroponic System

Hydrogen peroxide has been used as a sanitation agent for many years. Recently, hydrogen peroxide products have been used to remove algae from irrigation lines and sanitize hydroponic systems between uses. However, hydrogen peroxide can have phytotoxic effects on plants at high concentrations...

www.mdpi.com

• Findings on Plant Growth:
  • Lettuce: Shoot fresh weight was significantly greater in control and 3% hydrogen peroxide treatments. Higher concentrations of PERpose Plus and ZeroTol restricted plant growth.
  • Basil: Only cultivar differences for SPAD and plant width were reported.
• Findings on Algae Growth:
  • Algae growth was not significantly controlled by any treatment based on algae counts, weights, or spectrometer readings.
  • However, algae species quantification showed significant reductions in Microspora tumidula concentrations with hydrogen peroxide treatments.

Effects of Hydrogen Peroxide on Organically Fertilized Hydroponic Lettuce (Lactuca sativa L.)

Hydroponic production typically uses conventional fertilizers and information is lacking on the use of organic hydroponic fertilizers. Development of biofilm is a common problem with organic hydroponics which can reduce dissolved oxygen availability to roots. One potential solution is the use of...

www.biorxiv.org

Findings:

• Plant Growth: Conventional fertilizers with H₂O₂ led to stunted growth or death of lettuce plants. However, 37.5 mg/L of H₂O₂ with organic fertilizers resulted in yields comparable to conventional fertilizers without H₂O₂.
• Dissolved Oxygen (DO): H₂O₂ increased DO levels in the root zone, but its effects diminished over time. Organic treatments showed more drastic swings in DO levels.
• Fresh Weight: The highest fresh weight was observed in the control with conventional fertilizers. Organic treatments with 37.5 mg/L H₂O₂ had similar yields to conventional treatments without H₂O₂.
• Root Length: H₂O₂ significantly decreased root length, especially in conventional treatments.
• Leaf Width and Plant Height: Higher concentrations of H₂O₂ reduced leaf width and plant height, particularly in conventional treatments.