"Ocean ForestĀ® is pH adjusted at 6.3 to 6.8 to allow for optimum fertilizer uptake"
FoxFarm Soil & Fertilizer Company
Quick google :thumbsup:
So the soil seems to be optimal for its pH level. Have you add garden lime to the soil? If you have, that might have raised the pH to seven or over. Nutes usually bring the pH a bit down. To lower pH and increase acidity you can add sulphate of ammonia or urea which are high nitrogen fertilizers. Maybe try it to one or two plants and see if that helps. If your pH meter still shows 7 or over, test it to make sure It really works(unless you already have). You can pee on it ;)
Oh and keep the needle in the soil for good five minutes.