My DIY controller reads a pressure transducer hooked to my filter It's not wireless though. You could do something like that though.
If you're handy, here's the parts to make one.
Raspberry Pi Zero WH - $36.49 (you can hunt around online and they're like $15)
Amazon.com: Raspberry Pi Zero WH (Zero W with Headers) : Electronics
www.amazon.com
Battery - $40 (You could cut this cost out by plugging it into electrical at the pad)
Amazon.com: Pisugar Portable 900 mAh /1200 mAh Lithium Battery Power Module for Raspberry Pi-Zero, Pi-Zero W/WH Model Accessories (Not Include Raspberry Pi) (1200 mAh): Home Audio & Theater
www.amazon.com
ADC hat for the Pi - 17.95$
Buy Seeed Studio 4-Channel 16-Bit Analog-to-Digital Converter(ADC) Based on ADS1115 with Analog Grove Connector for Raspberry Pi Same Size as Pi Zero: Desktop Barebones - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Pressure Transducer - $16.90 (Screws right into the outlet of your filter at the top, can even put a splitter on it to keep your analog version)
Generic Carbon Steel Alloy Variable Pump Water / Air Pressure Sensor(DC 5V) - - Amazon.com
www.amazon.com
Then you just run the pressure transducer to the ADC hat and run software on your pi that reads it and transmits it to your smarthome software, or runs a webpage where you can view it, etc, etc. All wirelessly. I recommend node-red running on the pi to program it, it's simple to use and there's a few of us on here that could lend a hand should you need it.
EDIT: This ADC board is easier to use (no voltage divider, just plug and play) but it's sourced from a UK company
The ADC Pi is an 8 Channel Analog to Digital Converter for the Raspberry Pi with 0 to 5V inputs for connecting analog devices to your RPI ADC project
www.abelectronics.co.uk