Ok thanks for that. I also thought that underwatering may be it but then when im reading up online the rule seems to be water every two-three or when the soil seems dry. I am watering everyday however so guessed it would be enough? Although like i said the soil does seem pretty dry and is coming away from the pot edges.

Also the yellowin i mentioned on the other plant is getting abit worse... how do you recon best to proceed with the watering?