City water supply is NEVER consistent, no matter what they say. :wtf:
Always test your tap pH. If needed, adjust either up or down to the soil range of 6.3 ~ 6.8. You may find with experience, that it doesn't vary too much, or that it stays in the correct range. But, I would caution you, test it each time.

Your Fox Forest Ocean Forest soil is extremely rich. Many, many people burn their seedlings into oblivion with this stuff. Even without added nutes, so be really careful. Looking at your pics, plants look great, I really can't see any issues. Just be so, so careful when you add nutes and do it slowly (1/4 strength, then 1/2, etc...)

Edit: They are very dark green. May be overfeeding a bit. Cut back on those nutes and adjust your pH.