simply dose less and monitor your tank
there is no exact science to this... EI itself is simply a guide that should probably not be taken literally. most would be surprised how little I dose in my high tech tank. i still perform 50% weekly WC
your plants' reactions / nutrient levels in your water should be used as a guide. of course if you have a heavily stocked tank then you may not be able to keep nitrates in check without large water changes anyways. i am assuming this is not the case
i would aim for a 50% change every few weeks or a smaller 10-20% change each week... depends on what your situation is with water change setup, fish stocking, plants, etc... if i had a tank that large there is no way i would run it any way other than lower maintenance... that is a ton of water to change. you should also get a 'system' set up for doing WC on tank that large... plumb something outside your home so you can drain directly outdoors, rig up something to easily be able to fill tank, etc...
As someone who has 2 similarly sized tank I can do WC on all of my tank in under an hour and a half each week. on a tank that is 240g I would not even bother unless i had a LEGIT setup to perform WC. plumbing directly to the outside, easy setup to fill tank from water supply, etc... that is a tremendous amount of water to move. you will want it to be relatively 'automated'. i would set the tank up so i almost never had to vacuum the substrate, just drain water out, fill tank back up. done
basically... planning now will save you MANY hours in the long run