I'm going to throw this question out there since I know Ren's setup pretty well. What kind of distances and heights can you pump with a peristolic or diaphram pump? For example, can you go up 5' over 10' then down to the tank? Then he could fill up say a 10 gallon container and pump from that to the sump to prevent the chance of too much r/o.
myself, I'm running direct from r/o, through a drip valve set to slightly more than daily evaporation, to a solenoid operated by float valve. that way even if the solenoid fails, salinity will stay close to normal. I just can't get the valve to drip slow enough (after 3-4days the sump level is higher than I prefer), so the solenoid is more a safety for the drip valve than anything.
as for wavemakers, I've been told that you need one that slows the pumps down, but not completely off for the Koralias. Any truth to that?