Looking for ideas to plug 1/4" PVC threaded hole

[Delphinus]

Basically, I want to relocate the recirc line on my Ca reactor.

Simplest solution is to weld a piece of acrylic in or over the "old" hole, but that would require taking the reactor offline for 24 hours for the weld-on to set.

Would much rather use something like a PVC plug, because a few teflon wraps and it's watertight and the reactor's back online in 5 minutes.

But I don't think PVC plugs go down to 1/4" MPT. 3/8" for sure (as I have a bunch already) but I'm not finding anything smaller than that.

I'm thinking maybe a 1/4" MPT to 3/8" (or other larger) size nipple, and then a cap over that. Think something like that would exist? 1/4" pipe thread DOES exist, it's the same size threading as, say, furnace humidifier hookups. I have several fittings in this size, the problem is they all involve having tubing come out the other side.

Hmmm, I guess I could use one of those pieces, and then an irrigation plug in a 1" piece of tubing, and there's my plug. Hmmm, not terribly elegant though.

Or any other ideas? (I guess I could drill out the hole and make it larger, retap it, then use a plug. .... nah, that sounds like too much work, might as well just go with the acrylic plug in that case.)

PS. I don't have any spare acrylic to make a new flange, which I suppose would also be a workable idea. A new flange is more work than it's worth .... I'd sooner live with the recirc in it's current position.

TIA for any insights/advice!!