Flushing my plants?

Whats up.. So this time around im trying to make sure everything goes perfect. I have bought the entire line-up of foxfarm nutes except their flushing one. In the fox farm feeding schedule it suggests using their flushing solution every time I move on from one nutrient to another as stages in the plants life progress..

Is this really necessary? Can I just do it with regular ph balanced water? I read many different opinions but as far as the final flush should I go ahead and do it 2 weeks or a week prior to harvest? Also If im not mistaken to flush with regular water all I need to do is double the amount of water that I was watering them before?

EDIT//
Didn't really want to make a new thread so here goes: I currently have a 1000w setup in one tent. I am looking to cut down on time for the next grow. I am deciding if I want to buy another secret jardin DR100L (3.25x3.25) to Grow 12 clones while I flower in the main room. I have yet to decide if I want to use a 400 watt mh or if a 250 will be good enough just to get things rolling ahead of time. I plan on making my own clones (maybe 2nd time around) with one of those eBay aeroponic cloners made with pvc and a bucket for around $100. Any input is apprkeciated.

Thanks

you can use just straight ph water but it just takes longer to flush without the flushing nutes, i use final phase and ph water for 1 week and then just straight ph water for 1 more week then i harvest. the flushing nutes just shortens the time to flush, but you can use just straight ph water.

I don't even bother with PH when flushing, especially if doing 3-5 gallon pots. Just flush the piss out of it, let it sit a bit and then ph some water and run it through. You begin adjusting future waterings if needed. If you top dress the soil with lime, you don't have to worry much about the PH either, as it always seems to hold near 7 for me, even with 8 week old soil.