Hey Guy's,
Yes I agree, add perlite. I usually go about 30% perlite to 70% soilless media. I use Schuttz or Fafard potting mix, they both contain added nutrients, something like 008-012-008. The reason I use these two mixes is that they do not contain any time release prills(the little round balls). They can definitely through a curve ball into your feeding regiment. I looked everywhere for Foxfarm products and the only place in my neck of the woods to get this is on Amazon. I will not pay to have a bag of dirt shipped to my house! And yes, if I'm not careful my P.H. can get quite low 5.5, 5.8. I adjust accordingly when I prepare my water. Let's say your P.H. is at 5.8(run off), and your water is at say 7.4 and you need to be at 6.2. P.H. your water at 6.6. and this should get somewhere around 6.2.(I hope I'm right with this calculation but you get the drift). Also, yes most good potting media is neutral. Usually the nutrients in the soil will carry you through for two-three weeks. Look at your plant carefully, she'll let you know when she needs to eat.
Hope this helps,
DirtyNerd