So I tried to develop my first batch of film at home (after having them sent to labs earlier and getting mixed results).
I have ilford chemicals on order but this batch of development was with Foma chemicals - Fomadon Excel and Fomafix P.

I used the said chemicals in the following way for Delta 100 roll:

10 Minutes development time with vigorous shaking/inversion of the tank (as instructed in the Fomadon Excel charts)
3 minuted wash with water (with increasing inversion rates for every minute)
6 minute fix time. (as per Fomafix charts)

The result was a film with one partially developed negative, one very lightly developed negative and pitch black every where else.

I thought this was a bad result and wondered whether I could redevelop the negative again and went with 45 min develop time, 5 minute wash/stop, 15 minute fix time (no inversions this time, whatsoever).

Net result was a little more developed negatives of the 2 in the first time, everything else pitch black.

Reused chemicals on another roll of Delta 400 to see it wash into pitch darkness as well.

My questions would be this:

1. I mixed the developer to instructions that were similar to this link. And I saw some light orange residue being left over after dissolution (along with a pungent odour while mixing it). Did that result in bad developer?

2. Am I right in assuming that the fixer is okay and it was the developing solution that was either too mild or just not there?

3. My tank took a little over 500ml to fill up with both developer and fixer. Can one reuse the same? or would i have to really use much higher quantities of the developer instead?

[mods: trawled the pages using search but didnt quite find too related a page, please do excuse if repeat thread]