Since my CYA level is about 80-90 I have found it easier to maintain my FC at 9-11 to prevent excessive loss due to Las Vegas sun and high temps. I under stand that PH readings can be difficult to read accurately as FC approaches 10 or above. My question is... are PH readings at this FC level inaccurate with BOTH chemical and digital meter readings or are PH readings on a digital PH meter accurate at this FC level?