Is This Phosporus Deficiency? Please Advise

Using soilless mix with IONIC bloom & boost. Ph @6.0 ...2 plants are doing great but two others have slowed in growth and the leaves are twisted and tips are brown, some stems are brownish and there are brown splotches on the leaves at the veins. Seem a little crispy too but the soil is damp. How can I nurse them back to greatness?

Any clear pics of affected leaves?

Whats the temps, give us more detail of your grow to help us and you out.
Its like you just showing pics and no detail of the climate is us trying to figure out the radio without electricity.

Ok...this is bag seed of something supposedly "Amazing" that I got from my buddy that I started in March in Pro-mix soilless mix. These plants are into their 5th week of flowering. My room is 3.5 x 6.5 x 9 ft ceiling. I am using a 600w hps lamp. which is almost to the ceiling at this point because my other 2 ladies are really stretching for it. The lamp is being air cooled. The temp is usually betweeen 75 - 80 with an occasional spike of 85 lately with the hot days we're having here. Humidity is usually right between 47 - 55. Goes up around 60-65 after watering. I have an air conditioner helping to control the climate. These 2 plants were looking the best during the first 2 weeks of flowering...nice and bushy...with lots of triches. I had them located directly under the light for a while but now I have relocated them to the perimeter. Unfortunately, when I started flowering I was using the ionic bloom nutes 3-2-6 (3 tsp per gal) and the Ionic PK boost 0-5-6 (3/4 tsp) per gal EVERY SINGLE TIME I WATERED Then I read the instructions and reduced it to nutes every other watering and boost once per week. I also began adding Molasses 2 weeks ago. I added 1 tbsp to 2 cups of hot water then added 1/2 cup of the water mixture to1 gallon of my nutrient mix. I was watering about every 3 days but now I am trying to let things dry out a little more now than previously.

The plants in question are much smaller than the other 2...basically look stunted in growth. The new leaves around the flowers are dark green and slightly twisted looking. The pistils are also darker. Some of the leaf stems are also dark. At first I noticed the leaf tips getting brown and dried up and some leaves getting that brown splotchy vein so about 10 days ago I flushed all the plants completely with no less than 9 gallons of 6.0 ph'd water each.They just look like they are drying up basically yet the soil is definitely moist. It is odd because I have used the same nutes and watering schedule. light, heat and humidity for 4 plants...2 are great and 2 are not so great. I am constantly monitoring these plants and have never seen any signs of pests.

I was thinking of trying to lower the ph to 5.5 and add only the PK boost the next few waterings... Any advise would be greatly appreciated. Thanks

are all the plants the same strain? since your in the 5th week that is about the time that they will show a nitro def. from the stretch which could be the reason they are yellowing. the curling around like that could be a nute build up affect and just because you flush doesnt mean that will go away it just means that it probably wont continue. could be a cal-mag problem as well if you havent been using any. when did you stop giving grow nutes and switch over to flower nutes? the reason im asking is your supposed to keep giving them grow nute till just after the stretch along with your flower nutes. good luck and happy toking

Thanks for the help ... yeah, I did stop the grow nutes and went straight into the bloom and boost regimen. Do you think I should add some grow nutes at this point? Maybe 1/2 strength of each...grow and bloom? I believe they are all the same strain...what strain I'm not sure tho. I'm pretty sure if I don't change something to counter act this issue I will be left with very little yield