Do you have a protein skimmer running in your tank? It is a must for cuttles and will gradually remove a lot of the ink, secondly, have a bag of carbon running in a filter somewhere, it can also remove ink.
add an airstone or two if you can to increase water movement.
it is currently with so fishes and an anemone but divided from them and I do have a skimmer but it is not a very powerful one so it stills removes ink but maybe at a slower speed? will get the carbon soon most likely by tomorrow!
and for the water movement, my tank already has increased movement in it.
note also: if you spot an 'inking' shortly after it occurs (before it dissapates into all the tank water) you can usually skim it out with a fine weave fish net. At that point it's not as 'fluid' as you may think. usually my cuttle only inks when it is startled (which is usually by my entry into the room) so I am lucky enough to be there when it happens and I have removed all those inkings myself before they became trouble.