Accidental Over Feed.

It could be that all that organic matter you dropped in the tank has caused a bacterial bloom. These bacteria which live in the water column rather than in the biofilm multiply very quickly and we see them as the cloudiness. They feed on organic matter and water changes rarely solve the problem because you can't keep up with the speed they multiply. You have to wait till they've used all their food and die off.
Bacterial blooms usually occur in new tanks where the organic matter is plasticiser in the new plastic eg filter casing so you can't remove it and have to wait it out. But your organic matter is the solid food. Doing a water change was the right thing to do, but I would also do a daily water change for several days and give the gravel a good clean each time to get as much of the food out as possible. Less food for the bacteria means they die sooner. And keep a check on your ammonia and nitrite levels as any food caught in the gravel will decompose to make ammonia.
The only problem the fish might have, besides as potential ammonia/nitrite spike, is lack of oxygen as these bacteria will use a lot. Make sure the filter is rippling the surface, or even move it up slighlty so the water falls back in the tank - but not so high as to damage the filter.


And be careful next time 

My best advise is to put some tape over the flap on your food so you dont open the wrong end,


i`ve done the same thing twice now when feeding, till my brain kicked in

i bought some  small sealing tupper ware tubs and i tend to empty the food into the tub and store it there as its far easier to take a pinch of food from the tub than it is to try to get the right amount out from a shake of the packet or trying to squeze your fingers into a small tub or packet.

Normal service seems to have been resumed as soon as possible with the water clear again and the Tetra's are happy. Strangely enough they didn't seem to like the granule's much any way, after being carpet bombed with it They prefer the flaky type you shred into your hands.