Friz, the black tubing that I saw in the concrete boxes was 1/2" i.d. (I thought). I grabbed one of the splice connectors that was laying on the ground and I could swear that it was 1/2", but I've been wrong before!

I'll change the post to reflect the correct windmill.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).