I am currently using a DrDAQ directly connected to PC1, an old but normal desktop PC running Windows XP which is acting as a Server, then going via a 20 metre ethernet cable to the ethernet port of PC2, which is an environmentally friendly silent PC, continuously monitoring and recording day & night six different parameters of a central heating boiler using Picolog. This has worked fine all year, but now I want to add two more temperature sensors, using a second DrDAQ connected to the parallel port of PC2 which is also running Windows XP. I have tried this, and I am able to view the Picolog display which now includes the additional light and temperature sensors on the second DrDAQ (I selected those two for convenience as I don't have two more temperature sensors). In principle, therefore, I can see no reason not to be able to display the additional two temperature sensor traces at the same time as the original six traces. However, these sensors are going to be used to measure the temperature of the water in two separate water tanks. The water in both these water tanks is fed from mains water and is obviously earthed. The PCs are earthed, too and so too are both DrDAQs (via the PC's). Can you please advise me which additional two temperature sensors to use. I assume that the temperature measuring elements must be electrically isolated from the earthed water in the tanks, and must be compatible with, and connect to, the second DrDAQ. The sensors must not be damaged by continuous contact with water which will probably have a temperature range from 1 deg C to 35 deg C. The water temperature sensors are about 20 metres from the second DrDAQ which is directly connected to the parallel port of PC2. Please advise. Thanks.