Yup with Brick Top . . . .
Though flush normally, (GH florakleen is a brilliant addition to anyone's arsenal, helped me out no end when I was on my first rung of the ladder). Or plain PH'd water, but use 3 times the volume of water to the volume of your pot. 3 gal pot = flush with 9 gals. (with florakleen, you only need 10 to 15% run off, built up salt . . . .GONE
)
Then immediately after your flush; water what you would normally water with a small amount of P and K (and ideally trace) in the mix, 0-10-5 or around that level at 0.6 to 0.7EC
You don't want to be flushing out P and K at this stage
What's your tap water EC, and at what PH do you feed and water at please ?
~_