West Coast OG x3

Hi growers sorry I haven't updated my diary been away on holiday I'm back now and ready to go again. This is day 31 all 3 are growing good they've all started to flower the only problem I have notice since I've been away some of the leafs have started to yellow I've gave them 3 litres of water with 1 ml of big bud , bud candy , rhino skin and 2ml of cal/mag I'm hoping there's enough nitrogen in the cal/mag to turn the leafs back to green I'll update in the next few days I've also cut off a few leafs from the bottoms of the plants. Day 32 quick update all 3 have started to get burn on the tips of the leafs I really didn't want this problem so early on in flower. They have perked up abit but the top leafs are still abit yellow next feed I'm going to add some micro grow and bloom with some cal/mag. Day 34 I gave them 2 litres of water with 2ml of micro grow and bloom the leafs are still abit yellow and I haven't noticed much growth in the last few days I'm hoping there ok I think my pH may be to low with the small branches going purple and the burnt tips I'll update next feed or any problems.