Without knowing the exact details of your operational
environments (something we will need to establish) our initial
recommendations are as follows:
1) Sample and assess fuel quality in all tanks
(bulk, day, service, etc...) to determine contamination levels.
2) If contamination is detected (note that sample extraction provides
a conservative indication of contamination levels as only a small
area of the tank is assessed), perform tank cleaning and fuel
remediation services to the effected tanks.
3) Repeat 1 above on a regular basis or install fuel quality monitoring
equipment to tanks.
4) Repeat tank cleaning and fuel remediation services to tanks
that present sample contamination results.