Please guys please, any piece of advise really i need it!!! 
Could you post the build in short/long form because some of us like to comment at work but don't have Mids there. 
I will say that you need softcapped fire defense if you are using it for power leveling other toons. If solo ticket farming, just fill up on purple pez and chomp four a minute. Also, make sure the arc is all fire damage. Sometimes people use fire melee attacks that have some s/l damage as well.
I haven't looked at your build because I'm typing this from my phone. LOL
I've considered dm\fire for farming as well and I'm happy to share what I came up with; note, this build is based on my experience with my ss\FA brute farmer I've used for a long time (but I have 2 accts so eventually need another farmer and something different would be nice). Keep in mind you should probably have a build geared towards doing trials before doing the following one as incarnate powers are what make truely badass farmers possible, but without them they tend to be weak... with this build I would get everything to T4 before seriously farming and I would use the phantoms buffers for the AB buff (nice on longer maps like cave farms), ageless for the end, void for the -dmg part of the 'nuke', and degenerative for the -hp and toxic dmg proc in interface; without these incarnate powers the following build would really suck. As someone pointed out fire defense is important, but now that ambush farms have been gimped the Fire Cave Farm is king and I've found about 30% is plenty (without veng), with the heal up every 10 sec I still rarely need to use it, so I stock up on reds, not purps, once you are close to 30% fire defense acc\to hit (for non-ss brutes) and rech are most important. Anyway, any questions feel free to send me an email to acbolt42 at gmail as I don't check the forums much, or in game @ac bolt or @blazing stone.
Villain Plan by Mids' Villain Designer 1.956
http://www.cohplanner.com/
Click this DataLink to open the build!
Level 50 Magic Brute
Primary Power Set: Dark Melee
Secondary Power Set: Fiery Aura
Power Pool: Speed
Power Pool: Leaping
Power Pool: Fighting
Power Pool: Leadership
Ancillary Pool: Mu Mastery
Villain Profile:
Level 1: Smite
- (A) Crushing Impact - Accuracy/Damage: Level 50
- (43) Crushing Impact - Damage/Endurance: Level 50
- (43) Crushing Impact - Accuracy/Damage/Recharge: Level 50
- (46) Crushing Impact - Accuracy/Damage/Endurance: Level 50
- (46) Crushing Impact - Damage/Endurance/Recharge: Level 50
- (A) Aegis - Resistance/Endurance: Level 50
- (13) Aegis - Resistance/Endurance/Recharge: Level 50
- (13) Aegis - Resistance: Level 50
- (A) Superior Brute's Fury - Accuracy/Damage: Level 50
- (3) Superior Brute's Fury - Accuracy/Damage/Recharge: Level 50
- (3) Superior Brute's Fury - Accuracy/Endurance/Recharge: Level 50
- (9) Superior Brute's Fury - Accuracy/Damage/Endurance/Recharge: Level 50
- (11) Superior Brute's Fury - Recharge/Fury Bonus: Level 50
- (11) Endurance Reduction IO: Level 50
- (A) Doctored Wounds - Endurance/Recharge: Level 50
- (5) Doctored Wounds - Heal/Recharge: Level 50
- (5) Doctored Wounds - Heal/Endurance/Recharge: Level 50
- (7) Doctored Wounds - Heal: Level 50
- (9) Doctored Wounds - Recharge: Level 50
- (A) Recharge Reduction IO: Level 50
- (7) Recharge Reduction IO: Level 50
- (A) Luck of the Gambler - Recharge Speed: Level 50
- (23) Kismet - Accuracy +6%: Level 30
- (48) Karma - Knockback Protection: Level 30
- (A) Steadfast Protection - Knockback Protection: Level 30
- (A) Empty
- (A) Aegis - Resistance/Endurance: Level 50
- (15) Aegis - Resistance/Endurance/Recharge: Level 50
- (15) Aegis - Resistance: Level 50
- (40) Steadfast Protection - Resistance/+Def 3%: Level 30
- (40) Gladiator's Armor - TP Protection +3% Def (All): Level 50
- (A) Aegis - Resistance/Endurance: Level 50
- (17) Aegis - Resistance/Endurance/Recharge: Level 50
- (17) Aegis - Resistance: Level 50
- (A) Obliteration - Accuracy/Recharge: Level 50
- (19) Obliteration - Damage/Recharge: Level 50
- (19) Obliteration - Accuracy/Damage/Recharge: Level 50
- (37) Obliteration - Accuracy/Damage/Endurance/Recharge: Level 50
- (50) Obliteration - Chance for Smashing Damage: Level 50
- (A) Obliteration - Accuracy/Recharge: Level 50
- (21) Obliteration - Damage/Recharge: Level 50
- (21) Obliteration - Accuracy/Damage/Recharge: Level 50
- (37) Obliteration - Accuracy/Damage/Endurance/Recharge: Level 50
- (50) Obliteration - Chance for Smashing Damage: Level 50
- (A) Luck of the Gambler - Defense/Endurance: Level 50
- (23) Luck of the Gambler - Defense: Level 50
- (37) Luck of the Gambler - Recharge Speed: Level 50
- (A) Luck of the Gambler - Defense/Endurance: Level 50
- (25) Luck of the Gambler - Defense/Endurance/Recharge: Level 50
- (25) Luck of the Gambler - Defense: Level 50
- (36) Luck of the Gambler - Recharge Speed: Level 50
- (A) Obliteration - Damage: Level 50
- (27) Obliteration - Accuracy/Recharge: Level 50
- (27) Obliteration - Damage/Recharge: Level 50
- (34) Obliteration - Accuracy/Damage/Recharge: Level 50
- (34) Obliteration - Accuracy/Damage/Endurance/Recharge: Level 50
- (36) Obliteration - Chance for Smashing Damage: Level 50
- (A) Armageddon - Damage/Recharge: Level 50
- (29) Armageddon - Accuracy/Damage/Recharge: Level 50
- (29) Armageddon - Accuracy/Recharge: Level 50
- (31) Armageddon - Damage/Endurance: Level 50
- (31) Armageddon - Chance for Fire Damage: Level 50
- (31) Eradication - Chance for Energy Damage: Level 30
- (A) Endurance Reduction IO: Level 50
- (A) Hecatomb - Damage/Recharge: Level 50
- (33) Hecatomb - Accuracy/Damage/Recharge: Level 50
- (33) Hecatomb - Accuracy/Recharge: Level 50
- (33) Hecatomb - Damage/Endurance: Level 50
- (34) Hecatomb - Chance of Damage(Negative): Level 50
- (A) Recharge Reduction IO: Level 50
- (36) Recharge Reduction IO: Level 50
- (A) Gravitational Anchor - Immobilize/Recharge: Level 50
- (39) Gravitational Anchor - Accuracy/Immobilize/Recharge: Level 50
- (39) Gravitational Anchor - Accuracy/Recharge: Level 50
- (39) Gravitational Anchor - Immobilize/Endurance: Level 50
- (40) Gravitational Anchor - Chance for Hold: Level 50
- (A) Ragnarok - Damage/Recharge: Level 50
- (42) Ragnarok - Accuracy/Damage/Recharge: Level 50
- (42) Ragnarok - Accuracy/Recharge: Level 50
- (42) Ragnarok - Damage/Endurance: Level 50
- (43) Ragnarok - Chance for Knockdown: Level 50
- (A) Positron's Blast - Accuracy/Damage: Level 50
- (45) Positron's Blast - Damage/Endurance: Level 50
- (45) Positron's Blast - Damage/Recharge: Level 50
- (45) Positron's Blast - Accuracy/Damage/Endurance: Level 50
- (46) Positron's Blast - Chance of Damage(Energy): Level 50
- (A) Luck of the Gambler - Recharge Speed: Level 50
- (A) Blessing of the Zephyr - Knockback Reduction (4 points): Level 50
- (A) Empty
- (A) Empty
- (A) Empty
- (A) Empty
- (A) Empty
- (A) Empty
Level 1: Sprint
- (A) Unbounded Leap - +Stealth: Level 50
- (A) Healing IO: Level 50
Level 4: Swift
- (A) Run Speed IO: Level 50
- (A) Numina's Convalescence - +Regeneration/+Recovery: Level 50
- (50) Miracle - +Recovery: Level 40
- (A) Jumping IO: Level 50
- (A) Performance Shifter - EndMod: Level 50
- (48) Performance Shifter - EndMod/Accuracy: Level 50
- (48) Performance Shifter - Chance for +End: Level 50
Level 50: Degenerative Radial Flawless Interface
------------
Code:
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I've never played a Dark Melee farmer, but I copied over my SS/Fire build and tried to plug it in. I saw you had Hecatomb in your build, so I kept that, but I took out the other purple sets I use to keep the costs somewhat down. I don't think I would personally use a dark/fire farmer, but if I did, I would probably use a build similar to this one.
I saw you had tough running in your build but a good fire farm will not have smashing/lethal damage so you won't need it. (hint: search for 'reds') 
195% recharge, 30.1% fire defense. Get the Spiritual Alpha, ageless destiny, and reactive interface (I still find this the best option), and you are set.
I'm not sure but I imagine the attack chain would be something like:
Ball Lightning-Burn-Shadow Maul-Electrifying Fences-repeat
Villain Plan by Mids' Villain Designer 1.956
http://www.cohplanner.com/
Click this DataLink to open the build!
Code:
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I've been trying and trying to get this build be able to farm and not die.... But i failed
a lot.. Can anyone please help me make this a great farm build.
Here's the code for mids
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