I'm not sure why fronds have started turning yellow and dying all of a sudden,I'm pretty sure watering is fine as allways, I'm pretty carful tho looks abit like root rot possibly?
It's in 5-1-1 and been doing ok for a few months, I have noticed that leaves are starting to get scorch marks which can only be fertiliser burn so last 3-4 waterings have been plain water, always RO.

I have had alittle outbreak of scale recently, I have treated this palm and another Dypsis, I used a systemic spray so I was thinking maybe that but the other palm is fine, they both blew over when I left them outside but the other palm is fine, this came abit dislodged but nothing major, it went through a lot worse root disturbance when I repotted and responded fine to that.

Can anybody shed light on most possible cause as I'm abit unsure why its suddenly got sick, I can only think its now got nutrient deficiency as I've stopped feeding for a few weeks to flush but abit unlikely.

Just to add the pot looks abit big but I made it myself and when I did I packed out the corners so its pretty round inside and pot size is only about 1" bigger than it came in with plenty of drainage, I also tip the pot at about 45 degrees after watering to drain the perching water, (for anybody who might point out that 5-1-1 shouldn't perch it does :) )

Thanks