Seachem Paraguard contains no formaldehyde or methanol and will not alter the pH of your aquarium. Other products which make their way into the UK also use ingredients which have been banned by the VMD government department and could be deemed \" harmful\" Seachem Paraguard is the only fish and filter safe parasite control product available . Seachem Paraguard should be used whenever new fish are added to a community tank. Dosing Remove all invertebrates and chemical filtration from the aquarium . Use 5 mL (1 capful) of ParaGuard(TM) for every 40 L . Repeat this dose daily as required as long as fish show no stress.