Ok, so i was testing my ph in the res this morning and saw the ph at 4.8. Inittially i was like wtf is going on here so i added ph up rechecked and then noticed the pen is broke(of course i notice this AFTER adding ph up). So im about to head out to the fish store and try and find some aquarium ph strips until i can get over to the hydro store tuesday. Any other backup ideas you can think of please throw them my way. Muchos Gracias!