After struggling to find the appropriate size hole that would both flow quietly and not flush i finally found a solution. I cut a small slit into a screw type cap for venting. I am now silently circulating around 800 gph from the basement. I know that there are several variants to the general standpipe but this worked the best for my particular situation.
Hopefully someone else with a noisy standpipe will be able to use this idea.
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Hopefully someone else with a noisy standpipe will be able to use this idea.

