Speaking of failed black tank flush valves

[BB_TX]

Am curious about the failed valves. Mine failed. It was a round clear plastic valve with the manufacturer name (Lakeview, Lakeside, ?) moulded in the top. Mine had cracks all thru it and the outlet nipple completely broke off. I could not find a replacement at any RV dealer or web search. Finally found the manufacturer name on the internet, e-mailed him, and bought an identical replacement from him. But when I received it, I happened to look at it just right in the light and could see a lot of tiny cracks, particularly around the perimeter where the top section was mated to the bottom section. Also cracks in other radiused sections between the main body and the nipples. Appeared to be stress fractures. Sent it back and got a refund. Used fittings to eliminate the valve.
Now the question. Of those who have had failures, were yours the same brand and type of valve? Or a different valve?

I did later find a different style vacuum breaker valve on makariosrv.com and am considering installing one if it is not one that someone has also had fail.