What will cause the pH to drop a day after a 15% water change?
I have a one year old 150 gal tank
1 Sailfin Tang
1 Regal Tang
1 Gold Striped Marron Clown
1 Majestic angel
1 Coral Beauty Angel
about 100 lbs live sand and live rock
15 to 20 blue leg & zebra hermits and snails
green star polyps...