Avoid tank drain to sump through return - plumbing advise

[desi_reefer]

Hello everyone,

I have been reefing for almost a year now and started off small as a training tank and ended up doing all plumbing myself.

All went well, but then I realised that I made a mistake in my return line after I added the reactor. The mistake was I added a swing check valve right after my return pump i.e. Between the manifold and return pump. So when I turn off my return pump for any reason the water from my display slowly back flows through the manifold and through the zeo/carbon reactor and into the sump and raises the level almost up to the sump's brim. Last time when I had a power outage for a couple of hours the level in the sump rose and overflown skimmer had made a poopy mess all around, yuck!! I'm a clean freak by the way.


One nice afternoon I had some time and thought of fixing this. So, first problem was these swing valve are a pain to get here in Australia. Finally got one and put it in the return line after the manifold, and now that doesn't work (I was in tears, for all the pain taken), then I installed a union to check if there is a blockage, but no, its all good.

Now I definitely do want to fix this and If there is simple solution like a shutter valve at the return nozzle in display or adding a T off from the return (this is a major work) one feeding manifold and other return line? But dont wanna be doing anything wrong this time.

Please advise guys, thanks.

Photos below.

 

[Marc.The.Shark]

Check valves will fail in a saltwater environment. They may work for a while, but will get gunked up & leak by eventually. Best course of action is to plan & make sure that your sump can hold the overflow from the display tank. That being said, I run a check valve on my system so that the water level doesn't drop too far down when I feed my tank. I have found that the most reliable and easy to clean are the George Fischer Wye check valves. My sump will definitely handle all the water if it fails, but it is solidly built & incorporates a plunger stopper to restrict the back flow. I have yet to have it fail on me and have went 9-12 months between cleaning. They're not cheap, but they are the best if you want to incorporate one in saltwater.

http://www.bulkreefsupply.com/georg-fischer-wye-check-valve.html

 

[Neil Fox]

You could drill a small hole in the inlet to break the siphon.

 

[desi_reefer]

Check valves will fail in a saltwater environment. They may work for a while, but will get gunked up & leak by eventually. Best course of action is to plan & make sure that your sump can hold the overflow from the display tank. That being said, I run a check valve on my system so that the water level doesn't drop too far down when I feed my tank. I have found that the most reliable and easy to clean are the George Fischer Wye check valves. My sump will definitely handle all the water if it fails, but it is solidly built & incorporates a plunger stopper to restrict the back flow. I have yet to have it fail on me and have went 9-12 months between cleaning. They're not cheap, but they are the best if you want to incorporate one in saltwater.

http://www.bulkreefsupply.com/georg-fischer-wye-check-valve.html

Great thanks but these are not available here in Australia. I shall look at this though.

 

[desi_reefer]

You could drill a small hole in the inlet to break the siphon.

I have read this somewhere but I'm unable to understand this, could you please elaborate or is this anywhere in youtube or in readable article? Sorry for being a noob.

Thanks

 

[desi_reefer]

You could drill a small hole in the inlet to break the siphon.

In the pic below, my return nozzle is from the drilled back glass but not over the top of the tank, can I still be able to drill a siphon break hole?

 

[chefjpaul]

Raise the end of the nozzle more at water line, so less water back flows

 

[SteveSTL]

You can drill a small hole in the top of the return line inside the tank. If the power goes out or whatever, as the water flows back down the return, it will drain down to the hole and then suck air and break the siphon. You just have to make sure that you have enough free volume in your sump to accept the amount of water that will drain from the display tank.

 

[prsnlty]

You only need the tiniest drill bit and be sure you drill it on the underside below the water surface or it will spray water upward.

 

[Fin]

This is what I plan to emulate on my upcoming build...

Melev's Reverse Check Valve

 

[bblumberg]

No worries - we were all noobs once and there is always something new to learn.

I'd put some locline on your returns and bring the ends close to the top of the water. This way, the siphon will break very quickly when your pump shuts off. I did the "drill a small hole" in the return in a previous tank and found that it 1) got plugged fairly easily and 2) did not break the siphon as quickly as the return near the water surface.

If there is sufficient pipe between the manifold and the check valve, I'd remove from there to the union and replace with a true union ball valve or put a gate valve with unions. The siphon break from the locline will eliminate the need for the check valve. If there is not enough space, then cut just below the check valve, add a union there and replace the check valve with a piece of straight pipe.

Bruce

 

[Sleepydoc]

Welcome to the world of siphons!

As others have said, check valves are not the best idea for reef tanks. They almost universally fail and need to be cleaned on a regular basis. I've heard some people use them not to prevent back siphoning but rather just to make sure the display doesn't empty as quickly, which works, but they can also serve as a point of obstruction, so in general they are a bad idea, IMO.

Siphons occur when you have a solid tube filled with fluid and the water coming out the bottom end pulls water into the top. This will continue until the water levels are equal or enough air enters the tube to break the siphon.

For aquaria with sumps, the methods of dealing with this are:

1. Check valves (not ideal, as outlined above)
2. Drilling a hole in the pipe to serve as a siphon break. When a siphon occurs, it creates an area of low pressure at the top of the loop. A hole will allow it to suck air in to the pipe and break the siphon. The size of the hole required depends on the size of the pipe and the height of the drop. I'm not aware of any rules or formulas for this, so it's just trial and error. In general you want the hole to be under the water surface, otherwise it tends to cause a lot of splashing and salt creep. Either way, siphon breaks are prone to clogging/obstructing over time and need to be checked regularly. Even with that, a single snail can sabotage the whole setup.
3. A variation of number 2 is to have a setup like the open channel standpipe of a Beananimal return - have a tee at the top of the return pipe, cap the tee and have a small tube looping over so the end is just under the water surface.
4. Placing the pipe outlet close to the surface of the tank and sizing the sump so that the outlet of the pipe ends up breaking the siphon before the sump overflows.

Of these, #4 is the only surefire method. #'s 2 & 3 can be fairly reliable, but have potential flaws, and as you have learned, Murphy's law always applies with fish tanks!

 

[Skydvr]

From you pictures, it looks like you can rotate that elbow fitting towards the surface, then angle the accelerator nozzle back down while keeping it closer to the surface as suggested.

It will minimize the amount of water that isnsiphoned back into the sump.

Check valves require periodic maintenance. They get bio-fouled fairly quickly in aquariums.