Water & Fuel-Tank Treatment for Fishing & Marine in Namibia

The closed fresh-water circuits — main-engine jackets, auxiliary cooling — where mixed metals sit in hot, slow-moving water and corrode from the inside out. CCW 5 films the metals and its built-in indicator colours the coolant, so a motorman verifies protection by eye during rounds: colour strong, charge live; colour fading, top up. On a boat, a test you can do while holding a torch in your teeth is the test that actually gets done.

Descale first, then protect: a neglected circuit carries scale and corrosion products that inhibitor dosing prevents but only slowly reverses, so plan the Chloracid 90 descale in the yard window, flush thoroughly, then charge with CCW 5 and let its built-in indicator carry the daily discipline. Surveyors read maintenance logs — start the treatment log the day the descale finishes, and the indicator colour check makes every entry a ten-second job.

Because the growth never announces itself: the microbial mat in a diesel tank builds through a lay-up and blinds the filters on the first hard steam of the new season, when the boat is committed and the quota clock is running. Chemicide No 7 dosed before the lay-up sterilises the interface while the boat stands; dosing after it means killed sludge still has to leave through the filters. Either way, change filters after the first treatment of a dirty system.

The microbes live in the water, not the fuel — the condensation layer under the diesel is the habitat, and Namibian harbour temperature swings refill it nightly. Chemicide No 7 treats that interface; the sheet lists it for boats’ diesel tanks in so many words. Treat the bunker tank and the boat tanks both, and change filters after the first treatment of a dirty system: the kill is immediate but the debris still has to leave through the filters.