How to work a Multi-port High Output Air Pump

I've always just bought the 2 port Eco Plus Pumps and just connected both air outlets to a T-Joint And into 1 DWC bucket. 1 2 Port Eco Plus Per 5 Gal DWC Bucket, I did this to ensure I got over 100 GPH of O2 per Hour Min. Now I'm Trying to bring Unity to my garden, 1 Strain, 1 Medium, etc. so I went out and bought the 6 port 45 liter per Minute pumps to replace my air pumps Each port should supply each bucket above 100 GPH still but I am having uneven spread of o2 to each bucket.
Is this because of different lengths of tubes I have from port to each bucket?
Is it because they are spaced differently from the Pump itself?
How do I solve this problem?
Any Help would be appreciated.

place a valve on each line then you will be able to adjust the air flow to each stone

It has a 6 port manifold that has valves but I think it was because I was trying to use it outdoors and it was overheating but I'll try and install it in my Veg room to see if that was the issue. I already have the pump about a foot higher than water level are check valves still needed?