75 gallon tank

Well just to let you know you are not alone. I did the same thing although i was able to fix mine with a cut and a union.

Yes, I've done this once as well. I spent 10 minutes ripping apart what I'd just glued in 90 seconds, and another 5 or so trying to smooth out the melted zone for a new application. I hate mistakes like that.

Ripping it apart??? How do you accomplish taking it apart after it's glued? Use a holesaw to cut out the glued in pipe? I went to the store and bought another double union ball valve and tee, cut the end cap off for reuse and glued up that portion of the manifold again. About a $20 oops in parts, so not as bad as it could have been.

It takes tools and you have to act quickly. You can cut a former fitting and use a special boring bit to cut out PVC from a fitting that can't be extracted, but it isn't easy. I've used tools from dremels to needlenose pliers to cut out a mistake. New parts are always simpler, but sometimes you have to work with what you have because stores are closed.

I just did that with some plumbing I was doing. Mine has a happier ending because I realized before the glue had dried, but if it hadn't been a joint that involved some abs plastic... If that had gotten messed up though... I would've had to take out a bulkhead that was glued in place. When I had originally installed the bulkhead it got some primer on it and it swelled up. I ended up making my own wrench for the bulkhead out of a 2x4. It took about an hour, but I got the retaining ring screwed down and then I "installed" the next piece of my plumbing. Thankfully I realized what I had done in the nick of time and was able to rip out the piece. But hey, I feel you man. Better luck next time!

I want to see your 2x4 wrench!

With the "Red Hot Blue Glue" I'm using, I get about 2 seconds to get the pipe inserted and positioned the way I want it. After that it's not moving.

When I realized what I'd done (about 10 seconds after putting the 2 pieces together) I stood on the flange of the union (not much purchase but the edge of my shoes would just catch the flange) and pulled on the tee as hard as I could. It wouldn't come apart. That's why I was asking melev his method for getting glued pieces apart. I didn't know if you could add heat from a torch or something to loosen the pvc enough to get it apart.

Sorry, no I don't have a secret magic eraser for those kinds of mistakes. And it's easy to get hurt trying to pull these apart. I just hate waste, and will do what I can do avoid it when plausible.

Sometime you can heat it with a heatgun like for stripping paint and get them a part if it is not a really old joint. Plus a couple pipe wrenches. Been there and ruined that