No worries. Building a pool can be a bit nerve racking. Your pool is the same dimensions as mine.
So, if I understand correctly.
1) you have a couple of bubblers on a tanning ledge, and they have valves
2) There are 2 returns in the main part of the pool. No Valves.
If my understanding is right, I would indeed add 2 more returns, giving you 2 on one long side of the pool and 2 on the other.
Even though it would be OK not to add them, it would just be..... well blah, just OK.
Question: If you dont add them, will you be 2nd guessing yourself for as long as you have that pool?
If you do add 2 more returns, then here is my suggestion.
In the sketch below, the BLUE lines are the returns. There are only 2 on one side of the pool and there is a valve for the return line.
To add 2 more returns, just mirror this diagram to show 1 line with 2 returns on the other side of the pool, and have a valve on that return line. I think you get the idea?....
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