So my grandpa passed away in December and this is my first year of taking care of our (~20 year) old pool. I don't trust our local pool shop around here because they have left some jobs half done or done poorly for us in the past (no to mention charged twice for the same job because they didn't have a part and had to come back again).
Anyway, it's an old sand filter that seems to be working fine, I was just taking it apart to check for channeling and maybe deep clean the sand in it using the hose. When I removed the piping to the top multi-port valve part I noticed O rings between the pipes and the connection to the multi-port. The first two (intake and return after filtering) had O rings, however, the 3rd which leads to the backwash hose was missing it's O ring and has leaked for years when we backwash. I can't find any markings on the filter besides a P/N and S/N, everything else is faded. P/N WC112-148 and S/N 4918203080121Y. I've googled those and tried to find replacement parts and manuals for it. I get lots of details on all the parts INSIDE the filter or the parts for the multi-port but nothing mentioning what size O rings to use between the multi-port and external pipes. I also made a trip down to two different hardware stores and they have every O ring size under the sun, BUT the one that matches the two I have...
Anyone able to give me any advice or help on finding this O ring?