Hi all the above are what you need, just to let you know what I use.
1- Stress Coat in the top-up water when I do water changes, (15% every Sunday).
2- Melafix when I add new fish or make big changes within the tank.
3- Ground Shell, in my filters which keeps the water at the right PH, (you have to experiment a bit to find the right amount).
4- PH test kit, test once a week.
5- Ammonia, Nitrite and nitrate test kits, test once a month.
6- Flourish excel to help control algee growth.
Nothing else, but every tank is different so you will need to find the right balance to suit your tank/s.
Good luck