plumbing and back flow

[trump024]

I have a back flow issue that I know how to fix but I'm hoping I'm missing something simple and guys can give me an option or two that I'm missing
I have my return pump going to a manifold with 8 outlets. I have a check value before the manifold. 3 of the manifold slots are used for the tank and 3 are used for reactors. When power goes down and the reactors are turned off everything is fine. But when reactors are on and the power goes off the reactors drain the tank into the sump and it overflows. I have come up with a few options but I don't really like any of them. 1. I can add a "Y" before the check valve and add another check valve and re-plumb lines going to reactors. 2. I can use 1/2" check valves to the 3 lines going in the tank but I only have room for a vertical check vale not a horizontal. I haven't come across any all plastic, 1/2" check valves that can run vertically. 3. I can let the water line retuning to the tank not be submerged but then I deal with bubbles in the tank.
Maybe I can add a ¼" hose to tank return piping and not have that ¼" line submerged. I will get some bubbles but when the power goes out it acts like a air vent and stops water flow? Idk, any suggestions would be great.
Thanks

 

[RocketEngineer]

1) Get rid of the check valves. They don't work because something will grow inside it and prevent it from closing properly.
2) Place the returns to the tank just low enough so that as soon as the power is off, they suck air and stop siphoning. Mine are about 1/4"-1/2" under water and I don't have bubble problems.
3) The sump should be big enough to take all the drainage that occurs.

 

[d2mini]

1) Get rid of the check valves. They don't work because something will grow inside it and prevent it from closing properly.
2) Place the returns to the tank just low enough so that as soon as the power is off, they suck air and stop siphoning. Mine are about 1/4"-1/2" under water and I don't have bubble problems.
3) The sump should be big enough to take all the drainage that occurs.

+1 to all of that.

 

[KrazyKuch]

why do your reactors dump into the display, would it not be simpler to have them dump into the sump??

 

[trump024]

I guess I left this out... Your way use to work and would work if I didn't expand. I now have 3 60 gallon bays with a 60 gallon sump. After adding the 3rd bay, I put the check valve in since I have more water than the sump can handle in a power outage. (And yes the first check valve I put in failed so I'm not sold on check valves) The return lines are as close to the top of the water as I can get them. All my plumping is done with pvc, maybe I can take the 2 90 degree elbows going into the tanks and manually trim them from 2" to 1" where they connect. Thanks for the impute

 

[trump024]

The reason the reactor and refugium drain into the sump is because I am running 3 tanks off of the sump. I guess that’s another idea but a lot of pipes, I could have the reactors and refugium split 3 ways so all enter each tank. Has to be an easier way though

 

[RocketEngineer]

Pictures? Lots of pictures. I'm missing this whole bay thing impacting drainage.

 

[ca1ore]

I guess I left this out... Your way use to work and would work if I didn't expand. I now have 3 60 gallon bays with a 60 gallon sump. After adding the 3rd bay, I put the check valve in since I have more water than the sump can handle in a power outage. (And yes the first check valve I put in failed so I'm not sold on check valves) The return lines are as close to the top of the water as I can get them. All my plumping is done with pvc, maybe I can take the 2 90 degree elbows going into the tanks and manually trim them from 2" to 1" where they connect. Thanks for the impute

Not sure I'm really following this either. If you have the return to each tank, say, even 1" below the top surface, then a standard 60 gallon tank will siphon back about 2.5 gallons (48x12x1/231) - are your 'bays' not standard? Unless you have very little spare capacity in your sump to handle power loss, hard to see why this would result in an overflow.

While I agree with the ineffectiveness of check valves, if you must use them, the proper placement would be between the tank and the manifold. Otherwise the tank will just back siphon through the reactors.

 

[trump024]

No I do not have a actual fish tanks in use. I have 3 60 gallon Laguna pond tubs 42x28x12, the entire system is piped with pvc. Also I don't have pictures on me at the moment. Now that we are talking I think you guys might have solved my issue. I forgot I added a extension on the returns to help with flow while I was waiting for new fans. Since the fans are already in, I can now remove the extension and I should be good again. I will check it this week and send some pictures. Thanks!!

 

[btucker7587]

Pics would be good.

Don't see problem with check valves. I use a true-union check valve above my return pump and clean it during monthly maintenance. Have a utility drain above the check valve I use to take the backflow off of the check-valve when it is time to clean it. This runs the water to the drain that would backflow to the sump and I just consider that my water change refill measure.

 

[ca1ore]

Don't see problem with check valves. I use a true-union check valve above my return pump and clean it during monthly maintenance. Have a utility drain above the check valve I use to take the backflow off of the check-valve when it is time to clean it. This runs the water to the drain that would backflow to the sump and I just consider that my water change refill measure.

They work fine ..... until they don't. Any small debris that collects on the seat will prevent the check from sealing properly. With a short term pump loss, you may never notice; but any longer-term power loss will be problematic. Debates about effectiveness aside, there are simply better ways to prevent back siphon.

 

[btucker7587]

They work fine ..... until they don't. Any small debris that collects on the seat will prevent the check from sealing properly. With a short term pump loss, you may never notice; but any longer-term power loss will be problematic. Debates about effectiveness aside, there are simply better ways to prevent back siphon.

That can be said for anything. My DT is pre-drilled and the return holes are about 3.5" below the water. When I shut down and the overflow drains to my sump, I have roughly 14 gallons of wiggle room before overflow. Add the 21 gallons from the display tank and you have a crisis. If there is an easier way to stop the backflow on this, I am all ears.

 

[RocketEngineer]

That can be said for anything. My DT is pre-drilled and the return holes are about 3.5" below the water. When I shut down and the overflow drains to my sump, I have roughly 14 gallons of wiggle room before overflow. Add the 21 gallons from the display tank and you have a crisis. If there is an easier way to stop the backflow on this, I am all ears.

Why are your returns that far under water? Having the returns just 1/2" under the surface would drastically reduce the back flow.

 

[btucker7587]

Its how the tank was made, not by my standard.

Acrylic tanks are hard to find in Okinawa, so I had one ordered and sent to storage stateside until I could ship it here. Didn't get to see it for almost a year.

The placement isn't an issue in my opinion, but a check valve just above the return pump is a must.

 

[skeeter_ca]

To solve the problem add pvc to the return bulkheads that goes straight up to almost the top of the water then back down to where ever you want it. At the top drill one or two small holes that will act as vacuum break as soon as the water level drops to it. It will only drain back that much water when the pump shuts down. No check valves will ever be or should be needed. I can draw a diagram if you need it.

skeeter

 

[uncleof6]

Its how the tank was made, not by my standard.

Acrylic tanks are hard to find in Okinawa, so I had one ordered and sent to storage stateside until I could ship it here. Didn't get to see it for almost a year.

The placement isn't an issue in my opinion, but a check valve just above the return pump is a must.

Well then you need to build a bigger sump that can handle ALL power out drain down. It is not an option. The failure probability on check valves is 100%, and you are going to have a flood, not if, just when.

Think about this, ok so the holes are drilled way down the back of the tank. Can you not figure out a way to raise the outlets of the returns to within 1/2" - 1" from the water surface? (Without using loc-line which is not really water tight.) I don't think that is an insurmountable problem.

Another thing is that most tank builders are not flow innovators by any stretch of the imagination. All you get is their notion of what someone will buy. The holes should not be an issue, because who says you have to use the provided holes? Simple solution, plug the bulkheads and run a single return line over the top of the tank. It will flow better anyway, (less pipe and fittings) and not quite so much drain down.

The point here is you cannot depend on a check valve to prevent a flood. It just takes a little more thought to figure out passive fail safety and flood prevention.

skeeter: The failure probability of "anti-siphon" or "siphon-break" holes is 99%. The only way to prevent a flood is extra sump volume; if the sump does not have it, redesign the sump so it does, or replace it with one that does.

 

[btucker7587]

Well then you need to build a bigger sump that can handle ALL power out drain down. It is not an option. The failure probability on check valves is 100%, and you are going to have a flood, not if, just when.

Think about this, ok so the holes are drilled way down the back of the tank. Can you not figure out a way to raise the outlets of the returns to within 1/2" - 1" from the water surface? (Without using loc-line which is not really water tight.) I don't think that is an insurmountable problem.

Another thing is that most tank builders are not flow innovators by any stretch of the imagination. All you get is their notion of what someone will buy. The holes should not be an issue, because who says you have to use the provided holes? Simple solution, plug the bulkheads and run a single return line over the top of the tank. It will flow better anyway, (less pipe and fittings) and not quite so much drain down.

The point here is you cannot depend on a check valve to prevent a flood. It just takes a little more thought to figure out passive fail safety and flood prevention.

skeeter: The failure probability of "anti-siphon" or "siphon-break" holes is 99%. The only way to prevent a flood is extra sump volume; if the sump does not have it, redesign the sump so it does, or replace it with one that does.

As I said, Acrylic tanks aren't exactly accessible here. The cost for my exact tank (150G DT and 50G Sump) is $9000.00 USD here. Not something I want to buy.

I know check valves aren't reliable, which is why I built in the utility valve for water re-direct and got a union check valve. This is where routine maintenance comes in. Keep it clean and regularly check it. If I could get a bigger sump, I would. (hell, if I could get a bigger DT I would) but I can't. So I have to live with what I have. Eventually, I will square it up, but until then, I will stay vigilant on maintenance.

 

[mmn]

As I said, Acrylic tanks aren't exactly accessible here. The cost for my exact tank (150G DT and 50G Sump) is $9000.00 USD here. Not something I want to buy.

I know check valves aren't reliable, which is why I built in the utility valve for water re-direct and got a union check valve. This is where routine maintenance comes in. Keep it clean and regularly check it. If I could get a bigger sump, I would. (hell, if I could get a bigger DT I would) but I can't. So I have to live with what I have. Eventually, I will square it up, but until then, I will stay vigilant on maintenance.

I don't think they are talking about slow build up of clogging material, which your process probably would address. An organism causing a sudden clog will bite you.

 

[RocketEngineer]

I don't think they are talking about slow build up of clogging material, which your process probably would address. An organism causing a sudden clog will bite you.

DING DING DING. We have a winner. :rollface:

Ever seen a puff of hair algae floating around your display? Or those little snails that come out of the rockwork every night? Those are what is going to keep the valve from working. Murphy is mean.

 

[btucker7587]

DING DING DING. We have a winner. :rollface:

Ever seen a puff of hair algae floating around your display? Or those little snails that come out of the rockwork every night? Those are what is going to keep the valve from working. Murphy is mean.

"Murphy is Mean"...no, Murphy is a Ninja...

I know what they mean, and I have accepted that risk.

What I can do, however, is grab an EB4, pump and UPS, set up three sensors to detect the eminent overflow and have my Apex detect a power outage through my EB8's then pump the water to drain to prevent the overflow. Will be a good mitigation to reduce the overall risk.

I knew hoarding aquarium equipment would pay off. Well, either that or I have a problem...

But anyway, not to beat a dead horse :deadhorse:, but the setup will not change either way, The risk will only be mitigated until I can do a major upgrade. The conversation wasn't pointless though, it gave me an course of action to reduce the chance of an overflow. :thumbsup: