The installation guide, OBS-USR-M006-R2 Solo Tank Monitoring Kit Installation Guide is available for printing and downloading. The Help Desk article (based on that document) is here.
In order to successfully complete this procedure, all you need is your Solo's serial number and a credit card.
Registration
Go to: http://observant.net/signup, and select the Solo Tank Kit.
You will then see the following sign-up screen:
Enter the Solo’s serial number (located on the bottom of the Solo), and give the installation site a name. That name will be used to identify the Tank Monitoring Kit site.
If you have more than one kit to activate, click ‘Add’ and repeat, otherwise click on NEXT to proceed.
In the next screen provide the following.
● First Name and Last Name.
● Company or Property Name.
● Email address (twice).
● Cell phone number (allows SMS text messages to be sent).
● Password.
Click on 
to proceed.
If you have more than one Solo Tank Level Monitoring Kit to register, click on ADD, otherwise click on NEXT.
Confirm that you have as many tank kits as you have previously selected.
Enter the following Observant Global™ billing information:
● First and last names on the credit card’s account.
● Card number.
● CVV security code (typically the last 3 digits following the card's signature).
● Expiration date.
● Billing address.
Enter the following registration contact information, and place the order:
● First Name and Last Name.
● Email address.
● Phone number.
● Organization.
● Read and accept the ‘Terms and Conditions’
Click on Place My Order.
Once payment has been successfully processed, Observant will begin creating the Observant Global account.
An acknowledgment will then be emailed to the user with sign-in details.
Once the C3 Tank Monitoring Kit has been installed, sign in to Observant Global (http://obsrv.it) with your username or email and password.
Next, carefully read the End User License Agreement (EULA).
. . .
If you wish to do so, choose “Accept” to proceed.
Configuration
During the installation process, the following data should have been recorded.
You will need these three items to configure your Tank Level Monitoring Kit.
After logging in, the configuration View will appear automatically. You will have the ability to configure your Kit at this time if you choose to do so
If you haven’t already made the appropriate measurements, you can defer the configuration process until after the installation. Simply click on “cancel,” and you will be taken to the Monitor page.
After installation, you may configure your tank by clicking on the gear icon in the upper right corner. Begin the configuration process by entering the distance from the ceramic diaphragm at the bottom of the sensor to the bottom of the tank.
The button next to the units will allow you to choose to enter dimensions in either inches or meters.
In a similar fashion, enter the “head clearance,” which is the distance from the bottom of the sensor to the level at which the tank begins to overflow.
Choose “next” to continue.
Choose the water level display preference as either as the depth of the water (as shown here) or a percentage of tank capacity (as shown below).
Choose “next” to continue.
Set the preferred threshold levels (as a percentage of tank capacity) to establish the critical levels appropriate to your situation.
Check each box for which notifications should be sent. For example, if you check “Very high” and “Low,” you will receive an SMS (and/or e-mail) when the tank level either rises above the “Very high” mark or drops below the “Low” level.
Click “done” to save your chosen settings.
Finally, check to verify the tank level is displayed in the Observant Global system.
This completes the Tank Monitoring Kit’s sign up and configuration procedure.