Nurce top-off idea

OK. Not sure if that picture's working, but if it is, here's whats up:

Lots of people have said that the nurce top-off systems are a bad choice for saltwater, because through diffusion, the salinity of the two equalize. I think I may have found a way around this: It's pretty much your standard nurce top-off, except the outlet for the fresh water is above the surface. Normally, this would let air in and push the water out, but if you add a check valve, only water can escape. No air gets in. Only when the tube on top gets above your water level will the water squirt out.

the only part I'm concerned about is that the check valve may get caught in a halve open/ halve closed situation, and let air in and water out through the same tube. I'm pretty sure it works though, because I took a glass jar filled with water, poked a hole in the lid, ran airline tube through, and sealed it up all good w/silicone. I put the check valve on the end of the tube, and fliped it upside down. No water came out, because it was airtight, and the air couldn't get in through the check valve. I'll build one of these somemday, when I get a shelf or something next to my tank.

If you have something to say, please comment.

RESPECT

try this...

Not bad grizzle, you just drew out the plans for the autotopoff I'm working on. The biggest issue I've been facing has been finding a container that doesn't flex and get crushed by the external air pressure. I'm going to be using a liquor bottle that I emptied last weekend (washed, of course), and I just need to get the check valve.

Sounds cool. I think I'll try to find some sort of tupperware type thing that doesn't flex, or if I wanted to go bigger, one of those 5 gallon drums from the grocery store might work too.