I am trying to determine how much more NaOH than Ca(OH)2 it would take to raise the pH of pure water the same amount. For example: how much NaOH (say a solution of 1 gram dissolved in 1 litre) would it take to raise the pH of 1 litre of pure water from 7 to 8. How much Ca(OH)2 (again say a solution of 1 gram dissolved in 1 litre) would it take to do the same? I'm not so concerned about the actual numbers there as I am the comparison of how much NaOH it would take compared to Ca(OH)2.
My initial assumption was that it would simply take roughly double the amount because it had half the number of available OH- ions. However, that explanation seemed too simplistic to be true. I then did the math for the molar concentration of each and it was again just about double the amount. I'm just trying to find an equation to do the calculation properly. It's been quite a while since my University chemistry classes.
For context: I work at a small scale recirculating aquaculture system growing Rainbow Trout and we have been using Lime to maintain the pH (at between 7 and 7.4) and we are currently thinking about switching to Sodium Hydroxide instead, but are trying to determine approximately how much NaOH it would take to replace our Ca(OH)2 use. Obviously there are water quality considerations (like ammonia, nitrites, nitrates, etc.) but I'm just ignoring those things at this point.