Trouble with phantom xp orbs

[KingOfAllChunks]

Ok ,so here is my problem: Im playing the Ultimate pack and i have tier 5 wither skeleton , tier 3 creeper and tier 4 zombie pigmen spawners. The spawners are placed in the air, following 45 block free fall on conveyor belts, in which strangley half of the mobs survive ( i've tried with 100 block fall, the same result). So i have 13 malee turtles which kill the rest. Conveyor belts from there get the drops and xp into my sorting system. The problem is that the xp that comes out GIVES levels, but DOSENT despawn the orbs, which f*ck in my face and i cant get them out unless flying quickly somwhere. Then i got an XP turtle which sinks the xp and enchants stuff with it. Now, the XP turtle GETS levels, but the orbs still stay where they were. So after 10-15 minutes this gives out ALOT LAG (around 20 fps). My computer is pretty beasty (Assassins's Creed 4 without lag). So i have a crap ton of xp which just stays there and i cant pick it up (Phantom shuff) . Do you know any type of block that moves items and anything that falls on it gets fall damage? The phantom xp clears out after i relog (im on singleplayer). I think that the problem is in the Conveor belts, or in the 13 attack turtles. Last time when i DIDNT HAD this problem was where the mobs got killed from 2 attack turtles ON a transposer ( but i started using conveyor belts cause mobs sometimes glitch inside the transposer 0.o) Sorry for any spelling mistakes. I uploaded some schreenshots with the problem orbs (look at my xp bar. is it raising? i dont think)