After watching the replay of the 21min tackles by Pappas and what Zach did after the tackles, I think Zach has to be sent off, unfortunately.
Though Pappas had more reason to be sent off. His first tackle, I don't think, gets the ball. I think he gets the attacker's legs which then hits the ball. It is hard to tell. But you don't get to go through a player to get to the ball. The attacker has the ball on his side further away from the attacker. He lunges in and may or may not have got the ball. Either way, I think it is clear foul and yellow.
The second tackle is terrible. It's a straight red 11 out of 10 times. I have no idea what the referee was thinking. The kid was injured from the tackle. Pappas flies in from roughly 1.5 meters away and misses the ball connecting with the players with extreme malice just on or slightly above the ankle. An easy red card. Pappas could have broken his ankle or caused significant damage to the joint.
Zach can't do what he did even though there wasn't much in it.
For me, it's two send off's.
First tackle:
Image link:
https://gyazo.com/fa0bd296566d5ff74eef0b02718dd88e
Second Tackle:
1. image link:
https://gyazo.com/7e8f68a0fc35e7bf0d850c20904a5076
2. image link:
https://gyazo.com/93ec90ca912dcccbaabd3d165d782f6d