Having a little problem plz help!

OK so I'm using ffhf and LW haven't added any lime I'm using mix of the 2 with perlite a 50% LW 30% HF 20% perlite for seedlings and 50% HF 30% LW 20% perlite no lime I have two seedlings one is 2 weeks 4 days the older one is 3 weeks 5 day under a 400 watt mh in a cool tube reflector my temps at 68 to79 always under 79 my humidity anywhere from 28 to 30 okay now the older plant started out with a small little orange dot it developed into small rust looking patches the stem coming off the leafs are purple and dryed out darker green looking patches on the leaves the leaves are curling down and up. the younger plant looks good other then the humidity being way to low I think this might be the reason behind the curling up and the dry darker green spots I'm not sure I believe the other nuts in the mix is causing a mg lock out on my older gal really could use some help and guys I understand my humidity is way to low trying to fix it. I'll post pics if asked any help will be appreciated.

ok man first off ffof and fflw is what I I use to start seedling transplants. Works great!!!! FFHF is good too but I have never used it so I cant attest to it. BUT your RH is way too low dude. More like 40% is the lowest you go and that's in flower.

seedling---70-85% RH
veg--------50-70% RH
Bloom-----40-50% RH

Hold on are you telling me that temps jump around 10 degrees during lights ON? Try and stabilize your environment it's stressing out the plant due to temp and RH swings. I'm sure without even looking at your plants, the edges wavy and frilled.
I have a feeling you are over fertilizing and overwatering. Without pics I can't confirm that, but rust spots/patches is a calcium deficiency, the dark green blotches and purple stems is phosphorus deficiency. And to be perfectly honest with you, magnesium and a load of others are on their way.

From what I understand FFHF is a 5-5-5, even though the bags of soil don't list a N-P-K because there "ORGANIC", you should now have an idea of it's value. I always put lime in all my soil. Its a must when soil is peat based, as it has a tendency to return to it's acidic origin PH.

Throw up picture, what Tiki toker said is relevant but I also feel you may have soil pH issue that's locking out nutrients. Test the soil pH and get us a picture for a more fined tuned diagnosis.

Test the soil PH.... No that would be a waste of time... and a rabbit chase to end all.....
RH... no your plant will grow fine in that RH....should be higher... however, RH will not cause spotting....
A picture to fix your issue....
Otherwise... It will be the blind leading the blind, off a cliff for your plant and push reset button...
So either post up a picture....
Or hear advice from all of us speculating what you should do...

So...
Check your RH and Temp in the area between your Lights, and your plant canopy... and report back...
The area where the plant top spends most of its time.... That area could be 7-10 degrees hotter and RH of 7-10 points lower....
So that would cause a grow issue, but not spots...
Something splash, you spray something...
Anyway... Good Luck!

I'll get some pics up here shortly.

When I see leaves like that on my table it usually means the mix was a bit hot. Don't add any fertilizer, just water. If I were in soil i would test the ph with litmus paper just to be on the safe side. If the soils ph is way off, transplant.

Frilled and wavy. Tiki told ya. * fix the environment and PH, they will rebound.

The reason I say PH now is because they are necrotic blotching hat follows no specific pattern. Not to dismiss ca/mg, that too may also be a factor. Or high salts, but du to improper RH the plants has to take more water and as a concequence more nutrients with it, to keep up with elevated transpiration rates.

Thanks so most likely mix is to hot causing nute lockout? Making it P-K mg deficiency

yes also no need to transplant a flush will do you good and check PH after every watering and make sure to run a good amount of fresh water through the pot when you water them

Makes since I'll do a pH check keep the temp and rh constant no more nute

Hey guys Just got done checking pH and flushing watered enough to get a good run off and checked bigger plant was 5.7 smaller plant was 6.3 my rh hung around 40 today bought a small humidifier my temps have been up and down still trying to get that under control. Any more info would be appreciated thanks to all for your help and input.