Tank ready?

I have a long 20 gallon tank. I've had it running now for about a month. I have 2 marine land 150 bio wheel filters. I have a zoo med 24 inch led light with 18 bulbs. 6 blue bulbs 12 white. The blue is 465 nm 500 Mw each. The white is 6000k one watt each. The 6 blue bulbs are in the middle of the white. I have about almost 20 pounds of live rock. When I first got the tank that I added the water reading on the water was perfect. Only thing salt level was high. After things started getting a little bad. I did a half tank water change adding a gallon of distilled water. Out of no where 4 days ago the ammonia nitrite nitrate spiked a lotttttt but the salt level had dropped. Took the water to the lfs today and the guy told me the water was getting better. Today I removed 8 gallons of salt water and added 8 gallons of treated salt water from my lfs. About 6 hours later I tested the water and my reading were amonia 0 nitrite 0 nitrate 1 ph about 8.1. The guy at the lfs told me once I added the water today everything was going to be finally cycled by Sunday and that same Sunday I could already maybe add 1 fish. Can someone tell me if this whole process is going the way it should? If it is, what should be the next step? I forgot to mention I have added 3 peppermint shrimp and I am aiptasia free. I also have a small horse shoe crab and a Mexican turbo snail.