{"product_id":"sight-glass-in-line-1-1-2","title":"Hayward Sight Glass In-Line 1-1\/2\"","description":"\u003cp\u003eThe Hayward SP1072S is a 1-1\/2 inch in-line backwash sight glass. It is the genuine Hayward part, listed with Vari-Flo top mount 1-1\/2 inch valve parts for models SP-710X, SP-711-13, SP-711-20 and SP-712.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat it is for\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eBackwashing has one honest stopping point: when the water leaving the filter runs clear. Without a sight glass you cannot see that moment, so you either stop early and leave the filter dirty or run on and send hundreds of gallons of treated water down the waste line for nothing. The sight glass sits in that line and shows you exactly when to shut it off.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFitting and size\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThis is the in-line version, plumbed into the 1-1\/2 inch waste line rather than mounted on the valve body. It measures 4.5 inches long by 3 inches wide by 3 inches deep. A 2 inch version is available for larger waste lines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen to change it\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eReplace it once the body has clouded or stained to the point that you cannot judge the water, or if it has started to weep at the threads.\u003c\/p\u003e","brand":"Hayward","offers":[{"title":"Default Title","offer_id":48628738064596,"sku":"HAY-25-1521","price":42.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0801\/9568\/2516\/files\/default_5828a8d0-206f-4952-91ac-577b6e7e7400.jpg?v=1788749445","url":"https:\/\/www.activepoolsupply.com\/products\/sight-glass-in-line-1-1-2","provider":"Active Pool Supply","version":"1.0","type":"link"}