Quantity   Component name
1 × 12V, 3GPM, 55 PSI water pump This is a low-noise, high-quality RV water pump. See http://shurflo.com/rv-products/131-shurflo-revolution-pump-12-vdc-3-0-gpm for documentation
2 × Green 3.5 Gallon FDA Food Contact Approved Bucket and Top I got mine at ULINE, but 3.5 gallon buckets are relatively standard. https://www.uline.com/Product/Detail/S-9942GR/Pails/Plastic-Pail-35-Gallon-Green , https://www.uline.com/Product/Detail/S-9948G/Pails/Standard-Lid-for-35-5-6-and-7-Gallon-Plastic-Pail-Green .
10 × Parker LIQUIfit 3/8" push lock fittings Here's a link to the LIQUIfit catalog http://www.parker.com/Literature/LPCE/New%20PDFs/CAT_0563_UK_bd.pdf
8 × 30PFAF008-80 Spray Nozzle This is a 3/8" push-fit compatible spray nozzle. See https://hypro.pentair.com/en/products/18-hollow-cone-and-flat-fan-low-pressure-misting-nozzles for documentation
1 × Toro 53740 Drain Valve This valve is located at the top of the tower. It mechanically senses pressure to close when bottom valve closes, thus activating the sprayers.
1 × Sensorex pH1000 pH Probe After trying several pH probes, this one seems to be a good quality probe at a reasonable price. See https://sensorex.com/product/ph1000-light-duty-ph-sensor/ for more information.
1 × EC probe with platinum black electrodes and 10K thermistor This is a K=1 EC probe that is the standard probe for the CM-230 EC meter. It's around $20 from several sources on Aliexpress. I ordered it from https://www.aliexpress.com/item/1-00-Plastic-conductivity-electrode-CM230-electrode-5m-pin-plug-for-CM-230-Conductivity-Meter/32679762847.html and received it in about 2 weeks.