in some embodiments oil field fluids may have increased viscosity via addition of viscosifying agents such as polymers whether polysaccharide or synthetics the term u201c oil field waters u201d as used herein includes waters used in secondary recovery water used to hydrate polymers and water used in tertiary or enhanced oil recovery methods the oil filed waters may be fresh water or salt water e g an unsaturated aqueous salt solution or a saturated aqueous salt solution such as brine or seawater in various embodiments one or more biocides may be added to one or more oil field fluids and or wellbore servicing fluids the term u201c biocide u201d includes any compound or agent used to kill biological organisms and or microorganisms including antibiotics bacterialcides fungicides pesticides herbicides insecticides miticides rodenticides or combinations thereof as used herein the term u201c swedge u201d is meant to refer to any connection that serves to change the size or line threads with another connection disclosed herein are an apparatus and methods for treating tanks with biocide in embodiments the apparatus and methods eliminate the need for climbing to the top of a treatment tank to inject biocide into the tank in embodiments biocide is injected into the bottom portion of a tank in an embodiment the biocide is.