Someone in another thread was saying the same thing about return lines but in reference to not running sprayers at all.
Considering the work that goes into plumbing these bad boys I assume waiting till next round is best.
The pump sits in the middle of the res and is not hooked up to anything but the sprayers. As for running two I start to worry about water temps. I tried it before and the temps got a little crazy.
Then you have three options
1. Make the return lines larger. I've never seen return lines smaller than 3/4" My setup is identical to yours except I use
flora flex trays and it's 3/4" I pump 40 gph straight to the buckets and don't have a problem.
2. Add the line you are missing in this pic. Your water will level faster. Ideally this line should be there no matter what imo. And one day, I will get to it lol.
3. Get a variable pump and attempt to find the sweet spot.
Fundamentally, you have a water mobility issue. Gravity is doing its thing (as it always does) it's just that the water can't move quick enough. That's why option 2 works. It would be cheap enough to add option 3 too.
So, hope isn't lost. Even option 1 isn't terrible. The plumbing layout etc is done. You just need to tap new buckets and plug them in. It took me a bit to get used to my setup. You're 98% of the way there. Don't lose hope now. It's a simple fix.
If you can find an accommodating T fitting, I would make that tail piece 3/4", in case you change the buckets someday. Plus it's just more water mobility.