Bring the pH up. Use pH up or a small amount of lime. Don’t overdue the lime. Lime doesn’t work immediately and will keep raising the pH for a few weeks. If you use too much you won’t be able to get the pH back down.
It’s better to use Dolomite Lime because it has magnesium, which MJ plants use a lot of. All the different limes have calcium, but only Dolomite has magnesium. Dolomite takes longer to take effect, but last longer. Hydrated will react faster if you need to make a quick change with the pH. Some like to mix them half and half when quicker changes are necessary. If you use the same medium when you transplant, mix a small amount of lime right into the soil. Lime works best when mixed with the soil because it sticks. By that I mean it acts sticky and doesn’t water into soil that well. It also doesn’t flush out. Use one tablespoon per gallon of water and water one time with it. When mixing it with soil, start with one Tablespoon per gallon of soil and test the pH many times throughout the crop so you can make adjustments to the amount you used for the next soil mixing. Better to use too little than too much.
Peace