The compost in your soil is what your plants are feeding off of. Just be aware that by flushing you are not only flushing out salts but nutes and micro nutes as well. I'm not saying all will be gone but just keep that in mind. If your new growth starts to look lime green, they are asking for nutes.....

You want to use two to three times the amount of water you container is made to hold. In your case, you need to use 10-15 gallons per 5gal container in order to properly flush.....
CanGroIt Reviewed by CanGroIt on . 33 days into flowering, strange spots. nute burn or possible deficiency? Pic's. Hey folks, I just noticed these spots today on BOTH plants. They are mostly on the top fan leaves. I had problems earlier in this grow, corrected it and for the last 5 weeks things have been going good until now. Here is some more info and pics. What is your experience level? (first timer, novice, experienced...) Novice. Been at it for a few years. Your Equipment: .1) Type and wattage of lights. 90 watt LED + 2 x 42 watt cfl .2) Distance from tops? A few inches Rating: 5