Don't plumb RO/DI systems to a float valve directly

[Mike W]

At least once a week I get asked about plumbing an RO/DI system directly to a float switch. This is a bad idea.
Here is a post, with a good debate, from a while ago that pretty clearly states the reasons NOT to plumb an RO/DI system directly to a float valve as many are doing. RO systems are not meant for short run production.

http://archive.reefcentral.com/vbulletin/showthread.php?postid=345709&t=6440#post345709

[eddiem]

Actually unlike most float switches, Spectrapure's Liquid Level Controller is designed notto run in short spurts. The system only turns on once the level drops about 2" so that it maximizes the run time of the RO/DI unit(Not when the level drops 1/4", like most units.) Depending on the size of the sump (or tank), the system could run for some time before it refills the sump. This system also has a backup float swith to stop the unit in case the level gets to high.

The unit normally sells for about $80. I ordered mine from Marine Depot. I believe Spectrapure sells them direct for about $88.