yellowed blotchy dried out tips of leaves, 4 weeks flowering

i know that yellowing of the fan leaves is pretty common while flowering

but this seems to be more than just yellowing, in the pic below you can see some blotchiness, it's very dry when this happens, seems to come from the tip of the leaves going inward

it is happening on more than just the regular fan leaves, some of the leaves jutting out from the flowers are starting to to do this too

here's what the environment is:
soil - fox farms ocean forest, 1.75 gallon containers - was thinking maybe root rot, but this is happening on small plants i flowered way too early too, they are 2 months younger and still doing this
water - ro water, i'm scared of nute burn and am just using water for this time around, i get it from a facility close by that does reverse osmosis and uv and whatnot, pg is neutral when i testd
light - 250watt hps - this is happening in areas with 2+ feet between the light, can't be the light too close i'm assuming then
space - 18" x 30something" x 6' wardrobe, air intake at the bottom, air output pulling from light area to out the top, another small intake and output at mid height
temperature - 80 +/- 5

is this something i need to be worried about, or do you think this is just par for the course when they're flowering

i've searched and didn't find anything 100% conclusive on this exact issue i'm having, i have failed several times to grow, this is the first time i actually got anything to flower, the flowers are looking great but this is really starting to worry me as i'm so close!

thank you!

bump? =\ i'm a noob, this is the farthest i've gotten, feedback is super appreciated! thank you

I'm not a real old hand myself but it seems that if you have used no nutes at all then your plants may be starving. As a rather new grower myself I use 1/4 to 1/2 strength nutes because of burn concerns but I'd think more nutes would need to added to the soil at some point unless ocean forest has some kind of "time release" nutes. I don't think so. A little food is my suggestion.

Same thing happened to me, its a Phosphorus deficiency

thanks you guys

the reading i've been doing is pointing to nutes, phosphorous specifically

the fox farms ocean forest has some in it, but not enough to last through flowering it seems

i'm going to swing by a shop on the way home tomorrow and get something hopefully within my limited price range, just like appleseed i am going to do 1/4~1/2 nutes, wait a day or 2 and see what happens

appreciate you guys both taking the time to check, thank you!