This may be a good unit:
Neptune Water Monitor for your boat's freshwater tank: The first accurate and resettable water usage monitoring system for boat's and motoryacht's freshwater systems. Available in both US Gallons and Cubic Meters (accurate down to 1/20 litre)
This epoxy coated bronze meter is installed on the discharge or pressure side of your boat's freshwater pump complete with swivel couplings with 3/4" NPT ends. Accurate to within 1-1/2%. This meter was tested and approved by the California Dept. of Weights and Measures so you know it is accurate. The contact head register on the meter closes a microswitch every time 1 gallon passes through the meter. The remote resettable LCD register then advances by 1 gallon to indicate the amount of water consumed. Deduct this from your water tank capacity and you will know within 1-1/2% how much water is left, eliminating unnecessary fillups and delays.
This self powered remote register with a 10 year lithium battery is installed in any convenient and easily visible location you chose and connected to the meter with the included low voltage wire. You can put it in the galley, the head, the helm or by your engine access hatch. When you fill up just push the button on the remote and it resets to zero, ready to monitor again. As we know most water hoses run about 3 gallons per minute and much less if the marina is busy.
Filling that water tank can take more than 60 minutes so why do it if you don't have to just to be sure you won't run out. This water meter is accurate within 1-1/2% and is far superior to the various tank level monitors that can be off by 25% or more. Commercial vessels and vessels for hire must be certain they don't run out of freshwater and should have this system.
This accurate, durable and reliable system is priced at $199.95 including UPS shipping to anywhere in the Continental USA, a small price to be certain you won't run out of water on your next cruise or on the hook in your favorite spot.
We can ship your order the same day we receive it via UPS. We accept visa/mastercard/discover and PAYPAL to firstname.lastname@example.org
. You can fax, e-mail or phone in your order. Feel free to call us toll free 800-654-3733 if you have a question on this or any one of our many water and oil metering products.