I am a first time grower indoors, have some purple kush seedlings in rockwool cubes, it stated on the rockwool package to soak in pH 5.5. Now they are about 5cm high (2 inches) but the first 2 leaves seem like they have slightly burnt at the tips. Should I continue watering them at pH 5.5 until I transplant? I plan to transplant them into 75% ProMix and 25% worm castings as I was told to do. Do I switch to a pH of 6.0-6.5 only when they are transplanted?