Check valve question.

Not being defeated, I want to go back to planning to make improvements. I want to do my sump, want to get that skimmer still out of the DT. So I want to know from some of you about this valve from DRS Swing Check Valve True Union. I heard check valves are unreliable from stopping back flow in to sumps. is this true? Any experience with these ones?

 

Any check valve has the potential for failure. Your best insurance against excess backflow is to keep the end of your return line/nozzle at or near the water's surface in the DT.

 

+1, although I also use a check valve. Double protection.

 

Will its rare that the power would go out, it is a safety measure, but holy moly! $44 for a good one, I think I need to avoid that for awhile until things blow over.

 

Then all you really need to do is drill to 3/8" (IIRC, but you should double check on the size) holes on either side of the return pipe just below your water level. This will break the siphon that occurs after you shut the pump off and will minimize the amount of water that siphons into the sump.

 

Drilled holes and check valves are both a false sense of security. Both require maintenance and both still fail on a regular basis. Al it takes is a little food, some algae, an anemone or snail, a grain of sand on a check valves seat etc.

The only foolproof form of backflow prevention is a simple air gap, no cleaning, no maintenance, it cannot fail of be defeated and it costs nothing.

Water cannot jump uphill. As long as you keep your return close to the surface, only a very small, easily calculated amount of water can flow back until the return is exposed to atmosphere and the siphon breaks. In my case I have a 100G display with two returns set 3/4" below the surface using Loc Line and a maximum of 3.5 gallons flows back before the siphon breaks. (60"L x 18" W x .75" depth /231)

As long as you maintain sufficient freeboard in your sump a flood is not a concern and you can sleep soundly at night. There is no splashing noise as with drilled holes, no cleaning and no worries. Most sumps and skimmers work best when they are about half to 3/4 full anyway so a couple gallons of spare room should never be an issue. My sump is a 30G and it runs with about 18-20 gallons in it at all times as this is where the skimmer works best so there is plenty of room for an extra 3.5 gallons.

Never depend on drilled holes and check valves, they can and will fail, its not if but when!

 

My 15g sump holds about 12 gallons leaving little roon for error, I think I will still get a check valve and see if I can mod my return outlet to sit right at the service without splashing water everywhere. I am scared about drilling. I have seen lots of horror stories about that. bbuuurrr!!

 

Check valves will also contribute to headloss so your return rate will drop accordingly. They are not a good choice if at all possible.

Whay are you running so much water in your sump? This is not a good idea at all. It should be no moer than 2/3 or so full depending on the baffle heights. You are severly limiting yourself and asking for trouble. Is there any way to decrease the sump level for safety sake? I would sure recomend it.

 

+1 I run my 30 gallon sump with probably around 20 gallons. Basically the ideal way to deal with this is that you have your returns high enough where they are allowed to siphon as much as they can until they suck air, and for your sump to be able to handle all of this water. This is the case with me, although I do also use a check valve as mentioned.

 

ohhhh! The baffles came out of my 20 gallon, which does not fit in my stand, so I got the 15g which is the same dimensions, but 12" tall instead of 16" from the 20g, but everything fit, so that's why I used them. I guess I am really going to need to think this out.