You can catch phanphy in the beryl ward, evolve it and at level 30 it should learn magnitude
You also can try to sweep with emolga, put it in level 30, get +6 evasiveness with double team(against the skrelp), then you just need to use the combination nuzzle + electro ball, that's how I did...
Thanks, I defeated her, I evolved Flygon so Dragon Claw was OHKO against Dragalge, Blaziken destroyed Drapion and Venusaur, Gengar was OHKO'd by Murkrow (Critical Hit), Nidoqueen couldn't do anything against Flygon, thank you all for the help.
Thunder Fang can deal with Tentacruel, but Gengar and Dragalge spamming Sludge Waves... that's annoying, the nidoqueen is another nightmare, drapion can sweep my team with Aqua Tail and Poison Tail, the Venusaur is easy..., I'm going to catch some new mons.