buffer 8.3

hi, I bought one of the last (TOM DECO 3 AQUARIUM) I USED IT TO BUILD A BEAUTIFUL CORAL GARDEN. MY LFS SAID I NEEDED TO USE SEACHEM 8.3 TO KEEP A SMALL TANK IN BALANCE. I TRIED IT IN A VERY SMALL DOSAGE, MIXED FOR 6HRS WITH RO WATER. THE PH & ALK WERE LOW. I WOKE UP TO EVERY SINGLE TANK WALL...