Ciujbauanswered grow question 4 years ago Don't think the Cal-mag will do anything to the PH
Another suggestion from me : use spring water from shop , measure the ph and the PPM , see how different it is from what you use , if the spring water you buy has around 7.5-8 PH , use some squeezer lemon juice (Spring water i buy has nearly 8 PH , using 4ml lemon juice per litre of water and ph drops to 6-6.3 )
As others have said , soil is a great buffer , depends on what you used first , but should stabilize .
Use some 6-6.5 PH water might also add some nutes if the PPM is low enough (compared to what you used so far - but use less)