Check valve

[kvk]

I was at the hardware store today and saw 3/4" pvc check valves. I was thinking one of those would be cool on my return line to prevent siphoning to the sump in a power outage. However there seems to be some sort of metal screw in them. I assume it's stainless (they are built for water) but I'm wondering if installing this in a saltwater tank will give me problems. Anyone have experience with these things?

thanks,
Ken

[Larry M]

kvk--I would assume it's stainless since those valves are not made for use in salt water. I would not use anything that had a metal component. There are good valves designed for this purpose on-line if you feel you must have a check valve. IMO there are better ways to prevent a flood, these are far from foolproof.

Good luck,

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Larry M

Visit Reef Stores.com (http://63.75.34.139/ubbcgi/Ultimate.cgi?) The liaison between hobbyists and on-line retailers.

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[Dwayne]

I had a check valve in-line on the return. After a couple of weeks, I tested it. Well, it did slow down the flow, but it didn't stop it.

Try to arrange some other type of protection.

FWIW, IMO, YMMV, etc...

Dwayne

[Snailman]

The cheapest and best siphon break is a tiny hole in the in the line just above the water line. As soon as the power goes off and the pump stops pushing the water starts to suck back towards the sump. When it does this it also sucks air through the hole and the siphon stops. :) I learned this from a person that set up public aquariums. Check valves restrict water flow and will fail when you need them most. All it takes is a little bit of algae or sponge and it will not seal. :) It will slow the flood but it will flood none the less. :)

[Ironreef]

There are good check valves go to savco.com don't know the url but they sell clear ones and you know if its clean.I would only use a check valve for a back up to an antisiphen. I belive in murphys law I've had the pleasure to me him to many times so i always double up on safety from floods fires ect. double up nothings fail safe.

[FishWish]

Agreed, A good quality check valve make a nice second line of defense. The one you'll be interested in is a "Wye" check valve. These are clear acrylic with a rubber stopper and seat.
The siphon break hole just barely below the water line on your return is also nice.
It really is best to have your return above the water level completely,This is by far the surest anti-flood method I know.
Most of us around here are card carrying members of "The Flood Club". So heed our advise or you to shall gain membership.. :D..TTYL..David

[OrionN]

Two 1/8 inch holes (or more) just under the water line have never fail me in my years of keeping aquariums. Put at least one facing forward so you know it is open or not. Clean them when they overgrowth with coraline algae. This is very cheap and will work 100% of the time.

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Minh Nguyen
Visit my reef at:
http://sites.netscape.net/austinnguyen/homepage

[Ironreef]

another thing is placement of antisiphen hole. In the box under the top part of the return is best. Coralinne or alga will have a harder time growing. And with 10x turn over min. The water volumn will keep it clean. That and a good check valves lets me keep a spray bar on the bottom for good circ in a wide tank.I know many ppl who have hade these just will antisiphen that have never failed for 15yrs. But check valve will insure it.