It depends on the product you used. Maybe the debris is a result of the way your biocide kills the bugs. You should be able to setup a circulation pump
and run thru the existing primary w/o manual cleaning
My current boat
sat 6 years, no conditioner and had little care before that. I used algae-x and later switched to Archoil 6200. And to make a long story short, after a couple years got access to the main tank tops and cut in entry ports
an entered the tanks
. 3 600 gallon tanks
were clean. No water
, no sludge, no build up in the bottom. Whatever was there apparently dissolved and was caught in the filter w/o notice. After the first primary change I ran 2 micron w/o problems. I always add Archoil 6200 every fueling. Filters got changed about 500 hours w/o clogging.
I've been around marine
diesels for 60 years and never had to manually clean a tank. Even ships that were mothballed 20 years. But the diesel
was better then. I always reconditioned the existing fuel
and cleaned the tanks with filters, additives and circulation. If you're running an engine
that pumps and returns large volumes of fuel
, just using the engine should clean the tank. Keep spare filters. Use a good conditioner at fueling.