ouling;45305 wrote: Why not? Because I need to do a 80% water change right now.
Reefcast brought this up in a recent show as an area where many people are deficient in their disaster recovery plan. While most don't have an 80% water change worth of RO water lying around, let alone mixed, many people barely have more than the current bucket of salt.
A palette of salt might be a bit much for most, but if price is a concern, I'd think that a decent plan might be the following:
gpd capacty of your RO x number of days to get more salt at a decent price = minimum on-hand capacity.
Obviously, tempering this by your tank size is wise as well. If you've got a 50 gallon setup and a 50gpd RO unit, you probably don't need to make 250g of water in 5 days, but for those with larger displays, being able to max out your water production might be a good idea to have in reserve. Then again, that's less than 2 buckets of salt which is quite reasonable to have on hand.
80% water change emergencies are rare (I hope), but the cost of maintaining a deep bench (to borrow a sports term) for your salt is minuscule compared to what you can lose.