Natural or nute. diff.

In 6th week of flowering, DWC bubbler, 6 plants in 18g tote, DynaGro and now DynaBloom ferts all the way 1/2 tsp. per gal. Change watter every wk. 3 6in. air stones. 1000w hps and a 600w super sodium. 2 fans running 24/7, the fan on my 1000w broke need a new one. All 6 are clones from my last grow in dirt.
The leaves are getting brown spots starting at the outsides of the leaves moving inward or down the pic is a leaf cut from the kola. Is this how a natural n dif. looks at the end??
The last 2 are the different strains or types the the other 5 plants 1 is dif. then the rest.
Again as always thanks everyone for all your help an knowledge ya'll the best and have made my new found hobby a success for the start 2x's I've grown now and with it's minor prob's I got through it thanks to all who took the time to answer. And for your kindness may your crops return to you Ten Fold.

Peace.
:jointsmile:

my lazy attempt at help....

Revised: The Complete Guide To Sick Plants,pH and Pest Troubles - PlanetGanja.com

Thx bro I've seen that but still can't really get a diffinite answer I was hoping someone could identify it by the pic is the first pic in the attchments you can get a good look at the spots. Thanks again bro.

Couple things......please take photos with you HID lighting OFF so we can see the true colors of things.

That said, my first guess would be nute/salt/fert buildup in your medium, requiring a good flush of your system.

Good luck.

Thats what I came to also, thanks bro. I've had the FloraKleen just sittin wating for a time like this so I just put'em in a 2tsp./g bath I believe for Two hours as per directions, is that good anyone know better??
Again as always thx for the help and for sharing your knowledge.