Planted Tank Guru
Join Date: Dec 2017
Location: Elk Grove, California
A 30 gallon would be the minimum I would go. Ultimately, the goal here is , as you have made clear, to get maximum growth and health through several feedings daily and frequent water changes. It is a proven method of growing out both Angels and discus. But, need to keep all of those elements in balance: the amount of food/feedings, the amount and frequency of water changes ( and the ability by you to do them is another huge factor here), space for growth, the aggression of these cichlids/need for retreats for subordinates and markers to establish territories.
I would much rather grow angels or discus out in a tank that balances all these elements and ( also important here as I said) is easiest on you. The easiest and most effective method is actually not in the 75. Its too big.
If cant do a 30 gallon, however, the next best alternative becomes the 75.