I'm using tap water. It's pH is about 8.0-8.3. The first 2-3 weeks from seed, I'm not giving any nutes, so I have to add ph-down to my water to get it to be round 6.5.
Then when I start mixing veg nutes, my water's pH (after mixing the nutes) is about 7.4. So I still have to use ph-down to lower...