Auto Topoff/Float Switch

[lazylivin]

I am in the market for a top off unit. Because I have a waterline from my RO/DI unit going directly into the sump I was not needing a pump or reservoir just a float switch. However I have heard they can get stuck open. So I am looking for one with some additional safety measures. I found this one for 100$ that looks really nice feature wise. Has anybody found any DIY for top off or have experience with cheaper options?

http://www.bulkreefsupply.com/Auto-Top-Off-Systems/c72/p647/Level-Loc-auto-top-off-unit-for-RO-systems/product_info.html

[quicksilver]

I juse the Kent marine one never had a problem with it. I make sure nothing is growing on it an what not seems pretty good for not even half the price of what your looking at.

[Amstar]

http://www.reefworkshop.com/DIY_floatswitch1.htm