Hey - for those having this issue, and that have agitated their Rifts (don't put quarry on top of it!) to the point of no return (a major infestation) - I thought I would share my solution, that so far, seems to work.
Ive searched around (trying to fix mine first) and didn't find much info on it, but this is what I found out on my own.
First I deleted the Application Data\.technic\tekkitlite\saves\GAMENAME\DimensionalDoors folder. I replaced mine with a copy from an earlier backup. However I suspect that deleting the folder entirely will work.
Next I loaded the game. The black sparkles, black ender smoke, or whatever you want to call it - was still there, but not spawning enders anymore.
Next step was to download the mIDasGold app that can be found (on this site maybe) via google fairly easily. Then all you need to do is open the Patch.txt file in the app folder, and delete everything (if it isn't already) and add:
1977 -> 1
1977 is the block name for the ender smoke stuff and 1 is stone.
Then I opened IDNames.txt and deleted everything and added:
EDIT: Forgot to mention: in the mIDas app make sure to click Add Translation and be sure the 1977 is selected in the box to the left!
From there just run the app on your tekkit saves folder. You will go from a mess of rifts that cause lag, to a bunch of stone! The mIDas app even told me there were like 1200 blocks of #1977 (rifts) so yeah.. major infestation!
Also after this is complete I recommend going into the config folder and opening DimensionalDoors.cfg and change:
I:"How many times a rift can spread- 0 prevents rifts from spreading at all. I dont recommend putting it highter than 5, because its rather exponential. "=0
Could also turn this off I think with:
B:"Should rifts generate natrually in the world? "=true
However I didn't do that yet. Not planning on letting it go this far again!
Screenshots before and after:
Woohoo, now back to playing tekkit!
Have fun all, hope this helped someone!