Loss investigation should include gain investigation since with high water tables, underground tanks are as likely to suffer ingress as they are to suffer egress. Even double walled tanks with tight interstitial spaces can suffer gains. Most losses and gains though are caused by line failures and not by tank flaws and line faults are easier to find and less expensive to rectify.
With so much technology available, one might think that it takes a major investment to monitor for losses and gains but in fact it may take only a little attention to detail and perhaps a little professional help.
Gains of water are a worrying problem when 40mm gravitating to the tank floor can result in stranded vehicles and subsequent repair claims by customers before even considering the cost of repairs and the loss of sales while repairs are carried out. There are systems which can measure gains of 0.38 litres per hour but with water ingress, this is not good enough. 45 litres of water will show as 40mm in an average 10000 litre tank and 0.38lt/h is 9 lt/day giving an owner only 5 days before he has a major problem. He needs a system with much finer tolerances - MassTech can help where few others can.
Losses of fuel are a bigger problem but are normally easy to find. It may even be a simple paper exercise. If you want to be, you are in the hands of the experts who will not take over - rather they will become part of your team.
One thing you should know it that calibration errors in tanks cannot be a source of fuel loss but pump calibration errors can be.