i tested my reef aquarium for carbonate hardness add 1 drop it turns orange which is correct.i should be at 7-10 dkh but it never turns back to an endpoint of green ,no matter how many drops i put in. what does this tell me?i use ro water 8.3 ph,i use a liquid reef builder and buffer once a week and do a water change weekly.i have a 75 gal. tank thanks