Problems. please help

Hi all
I am growing Barneys PineappleChunk in 15l pots using canna terra soil...got them into week 4 of flowering and the older leaves have started to yellow and crinkle and some of the leaves are curling upwards.
Thought it was calcium deficiency and have upped the Ph to 6.5 a few days ago (was using between 5.8 and 6.2 which the canna flores directs) and added some calmag but it doesnt seem to have helped. the older leaves are still dying
Can anyone tell me exactly what to do to cure this? Have i completely misdiagnosed the problem? Will it become better in time?
I am using a 600w HPS on a 12/12 watering the plants every other day.(is this enough)
temps about 30 degrees with 2 fans running 24/7
I have added some photos of how the leaves are hope someone can help me sort this out

Pics of the full affected area would b helpfull outher than that go to plant probs in main menu and u will at least b able to look at a diagnostics chart and c wot u think.

Noticed u r in week 4 flower the plant will b drawing all the energy from the lower leaves this is normal and can lead to yellowing of the lower leaves .

I also r in week 4 of flower and have suffered the very same prob I have tryied just about everything to stop it but have been unsuccessful sometimes I think u just can't fight nature.

I think you may have a manganese defiency but I'm no expert. Here is a link to the guide I use to fix my plant problems. Whats good about this guide it covers soil/soil-less/hydro and so on growing styles and has solutions for each. https://www.icmag.com/ic/showthread.php?t=11688

thanks for the responses all is appreciated....will keep the ph up to 6.5 for as i had it at 6.0 and ive read calcium cant be absorbed at ph that low....hopefully it will return to normal and it is flowering great...no problems there just shitty leaves.....heres a few more photos that might help diagnose if anyone else is looking

holy crap ...that looks wicked bad. looks like a goner

I think you are on the right track with your diagnosis and treatment plan. Focus on your new growth for feedback.

Bugeye said:

I think you are on the right track with your diagnosis and treatment plan. Focus on your new growth for feedback.

Click to expand...

Agreed.

Yea bud theirs defo something not good happening their I'm not that experienced to b able to help I've never seen that kind of behaviour on any thing I looked at or read (and I've read a lot) like the more experienced guys said continue with ur plan and hope that does the job.good luck bud keep us posted.

Could it b they r root bound just a thought?