shouldnt water to much infact its rare u should have to water at all as the seedlings arent really sucking up much but if it goes dry definetly give it a water...an yeh somea mine have taken 10 days or so to pop out!! the root structure has to take root first before any sprouts so dont worry to much! concerning the Ph the prime should be 6.8-7.0 which is around neutral but the seedlings should sprout none the less..but if u are getin probs once it actually decides to show itself it could very well be the ph so keep a close eye...u might have to up the Ph..isnt hard!
Gd Luck!