Yellowing on edges at 27 days into flower

What's up people? I seem to have the same problem every grow. Plant's are decent looking during veg then around 2 weeks into flowering they start yellowing on the edges which leads to the entire leaf yellowing with necrotic spots and tips dying. I am guessing multiple issues. With the other girls I have tried adjusting nutes up and down with no success.

The plant in the picture is a Blue Magoo.
Soil is a mixture of forest compost, sphagnum peat moss, perlite, small amount of steer compost, small amount of chicken compost, garden lime, recently Top dressed with 1 table spoon of Jobes organic fetilizer 2-7-4. The yellowing started before the fertilizer was added.

Planted in a square milk crate lined with garden fabric (5'ish gallons). 1.5 gallons fresh water that sat out for two days (ph 7.14 ppm 180) every 2-3 days depending on weight (very little run off and it does dry out between watering). The soil ph , using a probe, is 6.4 and the runoff is 5.45....

Lighting is one 600 watt HPS and one 600 watt MH about 20 inches from the canopy. Temps bounce from 56 to 78 degrees between day and night. I am working on the temp swing.



I have used pre-mixed soils in the past and had the same issue so I decided to mix my own. Water does not puddle or stand and my moisture probe shows that it is not saturated at the bottom after a couple of days so I know it is drying out enough between watering.

Thanks for any and all help...

that's a pretty text book nute burn. But it's minor. It still will take time to recover. dead plant cells are dead plant cells - some most likely will not recover. Focus on new growth health for now, unless it get's worse.

I screwed up on the list. I did NOT top dress this with fertilizer. I have however fed with Canna nutes. I will give her plain water for a few waterings to see what happens.