I tried Teflon tape in my early years..

It never worked well on new metal fittings or fittings over 1/2" thread of any type material ( metal or PVC ).

Teflon tape does work well for small plastic fittings that are 1/4" and 3/8" ,
as commonly found under a sink or Reverse Osmosis drinking water system.

If you Tried Teflon Tape and you have a leak:

You need to be sure you have REMOVED 100% of any tape you used.

Then apply a thin even layer of Teflon Pipe threading compound.

And lastly, when screwing metal into metal, you must make the connection as tight as possible.

This usually requires two large wrenches.

A large Pipe Wrench to Hold the By Pass or metal Yoke, and a slightly smaller wrench to screw in the fittings,

using the first wrench to give you maximum leverage.

Since they are metal ( the fitting and the by pass ) you really can't Break Them or Over tighten.

This Video might help,

https://www.youtube.com/watch?v=prsgzY7aypE

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Pipe and Fitting Assembly Info - PVC Cement and Teflon Tape vs Pipe Thread Compound
****

PVC "Cement" is simple to use for "making" the Riser Pipe ( Bottom Distributor with PVC Pipe ).

Any brand of "PVC Cement" ( not glue ) can be used.
And when "making" the 1.05 O.D. Riser Pipe - with Bottom Distributor and 3/4" PVC,
be sure it's PVC and not CPVC, ABS pipe you are using to construct the tube.

Application Recommendations - PVC Cement:
How Long do you Wait after applying PVC to pipe / fittings?

You apply the cement to the Pipe ( thick layer and don't miss any spots ),
and the inside of the fitting ( or bottom distributor opening ),
AND when possible, turn ( spin ) the pipe for 10 - 20 seconds around in the fitting.
* Note:
When using "old" pipe or "dirt" pipe,
the application of "PVC Cleaner" or "PVC Primer" before the Cement is recommended.

Let it "set" for 20 - 30 minutes ( 1" or smaller sized pipe ), and it should be solid ( to handle ).
And if you let it "cure" for 1 or 2 hours ( if temperature above 60 degrees F ),
it should hold up when water pressure is applied.

Also reference this excellent Resource =
Instructions / Assembly - Home Depot

If you Tried Teflon Tape and you have a leak:

You need to be sure you have REMOVED 100% of any tape you used.

Then apply a thin even layer of Teflon Pipe threading compound.

And lastly, when screwing metal into metal, you must make the connection as tight as possible.

This usually requires two large wrenches.

A large Pipe Wrench to Hold the By Pass or metal Yoke, and a slightly smaller wrench to screw in the fittings,

using the first wrench to give you maximum leverage.

Since they are metal ( the fitting and the by pass ) you really can't Break Them or Over tighten.

This Video might help,

https://www.youtube.com/watch?v=prsgzY7aypE