slow & steady- slow sand filtration for hydroponics

7/27/2019 Slow & Steady- Slow Sand Filtration for Hydroponics

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May 2013 Written by Dr. Lynette Morgan font size

Sometimes taking your time truly does produce better results, which is why microfiltration using sand is one of the best defenses against nutrient-borne pathogens (and if youre careful, the sand wont get

into the cracks)

Battling the dreaded pythium and other root rot pathogens in a hydroponic system can be a demoralizing and long-term issue for some growers, with little in the way of effective chemical or other controls.

Even when roots look pristine, white and healthy, we all worry from time to time if nasties are starting to invade our hydroponic nutrient or causing issues without us even knowing what might be occurring at

the microscopic level. One of the best defenses against nutrient-borne pathogens is other beneficial microbes. In fact, if present in high populations and combined with effective microfiltration, control overproblematic phytopathogens becomes an extremely effective practice.

Slow sand filtration

SLOW & STEADY: SLOW SAND FILTRATION FORHYDROPONICS

Slow & Steady: Slow Sand Filtration for Hydroponics http://www.maximumyield.com/inside-my-com/features-articles/item/789-slow-steady-slow-sand-filtra...

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inside the filter. While its not a requirement to inoculate a new filter with microbial mixtures, as these will naturally develop over time, it is advisable to age a new slow sand filter for a few weeks before it is

required to treat nutrient or water. Microbial populations also work most effectively in warm temperatures, with sufficient oxygen and with moisture; so, the filter material should not be permitted to dry out,

even when not in use.

Slow sand filtration, if constructed and run at the correct flow rates, is highly effective against a wide range of root disease pathogens that can be carried in the water supply or nutrient solution. As a passive

disinfection technique, slow sand filtration is easy to set up, cost effective, environmentally friendly and low maintenance. Its only limitations are that some space is required to house the filter and that it is

largely ineffective against viruses and nematodes. For indoor growers experiencing ongoing root rot pathogen problems, slow sand filtration could be one of the best options for safe, long-term disease

control.

References and sources of information

Spatial and Temporal Analysis of the Microbial Community in Slow Sand Filters Used for Treating Horticultural Irrigation Water. (2003). Applied Environmental Microbiology, Vol. 69 (Is. 4), 2116 2125.

Barth GE, Hall B and Chinnock S. (1997). The Uses of Slow Sand Filtration for Disease Control in Recirculating Hydroponic Systems. Proceedings of the 4th National Conference of the Australian

Hydroponics Association.

PUBLISHED IN 2013

Dr. Lynette MorganDr. Lynette Morgan holds a B. Hort. Tech. degree and a PhD in hydroponic greenhouse production from Massey University, New Zealand. Lynette is a

partner with SUNTEC International Hydroponic Consultants and has authored five hydroponic technical books.

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slow & steady- slow sand filtration for hydroponics

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