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By Bob Fenner

The single most common vector of carrying disease from one system to another is by way of nets, specimen containers and other catching equipment that wipes off skin, slime and disease-causing organisms from one batch of organisms to another. This pull-out describes a simple, effective dip & rinse treatment for reducing spread of infectious disease.

Transmitting toxins and disease-causing organisms between systems can be easily curtailed with the conscientious use of a sterilizing dip and rinse solution. Nets and specimen containers used for capturing and transporting livestock are especially suspect, but all systems and components should be thoroughly cleaned/sterilized between use to eliminate cross-contamination by different plants, fishes and invertebrates.

Dip Solutions:

Many different chemical preparations have been and are being used; all with their concurrent strong and weak points. The following is a brief description of the most common:

1) Halogens: Chlorine, bromine, iodine bleach solutions are too dangerous if not removed thoroughly, are damaging to nets and other equipment, and are outright too noxious for humans.

2) "Dye Solutions": Potassium permanganate, malachite, flavines and others are hard on your gear, messy (stain everything) and may lose strength without indication.

3) "Salts" are ineffectual for many poisons and pathogens, given common concentrations and dip times.

4) Ammonia-based compounds: like Roccal are much too dangerous for non-recirculating or non-open systems. If not completely rinsed off, the dip will kill your livestock.

So, what to use?

The Solution: 

Formalin or formaldehyde is the best. Inexpensive, readily available and relatively safe to use. It doesn't stain, won't oxidize netting or harm you if used conscientiously.

The Set-Up: 

Two water-holding buckets; one for a dip the other for rinse.

The Dip: 

A few gallons of tap water and an ounce or so of 37% (standard, stock concentration) formaldehyde.

The Rinse:

Warm to room temperature tap water. 

Generally, these dip and rinse solutions should be re-made every day. In heavy use situations the formaldehyde may be "used up" more quickly; whiffing the dip solution to ascertain that some detectable strength of formaldehyde is present is suggested. Our stores in San Diego, California, Wet Pets, add a few drops of methylene blue to the dip solution; for one to distinguish between the dip and rinse solutions, and two, as an indicator to renew solutions when the rinse becomes blue.

Formaldehyde is available from Kordon and other aquatics manufacturers in small quantities. Ask your dealer for it.

Operation: 

Between uses, nets and specimen containers are dipped briefly or stored in the dip solution and then rinsed in the rinse solution. Simple enough? If some small amount of formaldehyde is transferred to the live-holding system, it should not present a problem; many aquarium therapeutics and water conditioners contain substantial amounts of this preservative.

Formalin/formaldehyde is toxic in high concentration. Though it is a frequently encountered household compound, it should not come in contact with your skin in full concentration. Spent dip and rinse solutions should be poured down the toilet or sink.

Other Techniques: 

Physically drying, rinsing in hot water, using physical sterilizers are time-consuming and not always effective. Using a separate set of equipment per individual system is perfect but laborious and expensive.

Make and use dilute formaldehyde dip solutions daily and you will find your disease-incidence rates reduced considerably.