PH problems in flowering

[Mario]

Hello, I have huge problems with my 2 autos which I was stupid enough to plant in 5.5 ph soil from local garden store (sorry for my ignorance). Now they are 48 days old, one of them has a purple looking stem with almost no healthy leaves, but has some sugary buds forming, the other one is looking better, it has much more green leaves, but lots of brownish too with random yellow spots. Now I have these dieing autos ... What would be the best thing for me to do at this point? Will I even get anything out of them or is it time to start a new grow ?
Thanks.
Photos :

 

[Waira]

..need normal light pics please, and fill out the patient form in the colored section above this one,.. just c/p it into here and fill in,...

 

[Mario]

Problem: Looks sick

Medium/grow method: Random soil from garden store 5.5 ph.

Feed: and supplements used: Biobizz grow and bloom, watering every 4-6 days
water source: Tap water ~7.4 ph

Strain/age: Northern Light and Royal Jack
light used: For the first 4x 45W CFL for the first 25 days, from then 300w Meizhi LED (135w)

Climate: 23-28C

Additional info: Both plants had problems from the beginning. Leaves looked kinda burned later they fell off and the new growth was alright. Around week 5 royal jack's leaves started getting all kinds of dark spots on them and started curling upwards. Eventually they got very dry and crumbly, a lot of them fell off. The Northern light is looking better but definately not alright. At around week 5 all top leaves were drooping like crazy for a whole week but later it fixed by itself. Now the leaves look very discolored and have yellow spots

.

 

[namvet25]

Are you watering with 7.4 ph water?Did you use any cal/mag? How close are your lights?

 

[Mario]

Yes I am watering with around 7-7.5 ph water and I dont use any cal/mag or other nutes, only biobizz grow and bloom. Lights are 9 inches from the tops.
And forgot to mention that at around 4th week there were some fungus gnats flying around, I got rid of them with sticky traps and diatomaceous powder and there seems to be no more gnats left but maybe theres larvae deep in the soil and they are eating the roots ?

 

[namvet25]

Your main problem is watering with to high PH.It should be between 6.3 and 6.5.You should always use Cal/Mag especially during flowering.Also your light is to close so raise it upto no closer than 18 inches from top of your plant.Do you have any PH down liquid? and can you get some cal/mag/

 

[Mario]

I thought that 5.5 PH soil is to low. I will get the ph down then. Is there a huge difference between PH down for veg and PH down for flowering, or should I get both for future grows ? Unfortunately I wont be able to get cal/mag.

 

[namvet25]

I thought that 5.5 PH soil is to low. I will get the ph down then. Is there a huge difference between PH down for veg and PH down for flowering, or should I get both for future grows ? Unfortunately I wont be able to get cal/mag.

No difference.can be used for veg and flower.Are you in the USA?

 

[Mario]

Okay so now if I start watering with 6.3 PH water will these plants recover? I am most concerned about the one with almost no healthy leaves. Will the trichomes even develop without them? Maybe I should get a new plant instead of wasting time ?
Thank you for all the help
I am from Europe btw.

 

[Waira]

yeah, soil pH is too low, likely at the core of the multiple problems,...probably the soil was off to begin with,.. what brand is it?.... how are you testing the in-pot soil pH? We need to confirm the accuracy of that reading,...Sorry for the confusion, but watering with lower pH adjusted water is making matters worse,... No differences in pH up/down for veg' or bloom,... soil ph should be mid 6's,... I think you have both pH lockout and some plain old lack-of nutrient deficiencies... Biobizz is very mild stuff, and you need to be using most of the line to get truly complete nutrient coverage... I think Alga-mic (?) is their micronutrient supplement....
yellowing at the tops is looking like a micronutrient defc., likely Zn,... lowers could be really bad P defc. or a combo of things,...
... pending the soil pH confirmation, you may need to do a flush, 2-3x pot volume of good clean water, ...