I’ve been using the Fibaro sensor with temp probe for several weeks now. I drilled a hole for the probe tip in one of these boxes and sealed up with some silicone gasket maker and dropped them inside the skimmer openings. With the exception of the enclosure screws rusting (probably will replace them with some stainless ones), everything has held up ok so far.
https://www.amazon.com/gp/product/B019OD74S4/ref=oh_aui_detailpage_o05_s02?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00P2QAR8C/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00IYE4X70/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1