i personally dont like adding tablets and powders to my ciders (or beer) and tend to go all natural. I usually use a few raisens for a pectic enzyme sub and black tea for a tannin sub. They work great.
Also, you can keep it simple and still end up with a great product. One of my favorite ciders is only 2 ingredients--Motts apple juice, and US-05. Let it go dry and bottle with no carbination.
The cider i make time and time again and is mine (and SWAMBO) favorite is motts juice, brown sugar to bring it up to 1.065, and 1 lipton tea bag per gal juice. Let it ferm out dry, then secondary with 2 lil sweetie oranges per gal. I usually slice the oranges and soak them in a little vodka. I will let them sit in the secondary for 3-4 days then cold crash and bottle. Le residual juice from the oranges carbs them up nicely to a guess of 1.5 vols. I really dont like my apfelwine/cider carbed, but this on i like it lightely carbed