[Oldschoolsalter]

This is a general question...not an issue post.

When a basement return pump is shut down, during water changes (or) for maintenance, just how much air ends up pumping back to the DT after the pump is restarted?
It seems like the plumbing would hold quite a bit of air...right?

Do people shut off a valve on the return line, to prevent this?
Then re-open prior to pump start-up?
Or use a check valve?

Are ball-valves fine for this operation?
(Repeated useage.smoothness, or flow-restrictive)?

Just wondering...

THX

 

[St99iff]

Mine wasn't in the basement, but I used a check-valve. I had my return going into a SCWD and each output from that branched off twice. So I had my return basically split 4x. I chose to use the check valve as opposed to guess-timating where to put holes in each of the returns to break siphon.

Then when I was doing water changes, I just unplugged the return pump and that was it. Plug it back in when I'm finished and think nothing more of it.

 

[Pitter98]

I really don't think much air at all is pushed up through the line unless your water level somehow gets to low so the pump can suck in air. Even when the water completely empties into your sump, there is still a foot or so of water in your return line (whatever the sump water depth is), so the pump is still submerged. I have never seen any air coming out of my return line, but to be honest it's usually a minute or two after I start the pump back up before I get back upstairs to see the display. It is always clear by the time I get back there (other than gunk that gets stirred up by turning the pump on/off). My drain line always has a ton of air in it when it starts back up, but that is because my overflow completely empties when my pump shuts off.

 

[Oldschoolsalter]

Air Slug conclusion -

I guess, why this normally never occurs in my current set-up, is because of vacuume break(s) that exist in my internal overflow system.

I know the Durso stand pipe drain has one.
I believe my return line also does.?

This must vent the air on pump start....perhaps?

 

[Oldschoolsalter]

Massive Air-Slug on pump Start-Up - Confirmed!

Just as I had thought would happen, did.

Massive amounts of return line air gets pushed into tank when pump has been off.

This possibly wouldn't be quite so bad, if my return wasn't so low in the tank.
But it exits my overflow box, then 90's down to about 2" off tank bottom.

Naturally, all the fish freaked when this happened!

IF I had a vertical section, on my basement plumbing, I might consider an in-line check-valve.
Unfortunately, my plumbing run really doesn't.:sad:

Wondering if one of those "split surface-style" (LOC return) could be beneficial for this issue????
Like this style:
Aquarium Return Loc Line 3 4 with Dual Nozzles | eBay

 

[stoelton]

If you drill a siphon relief hole into your return line ~1 inch below normal water level, the air will take the path of least resistance and go through that hole near the top of the tank.

If you do not have a siphon break, then you risk draining the tank if you do not have a check valve. During a power outage or when you turn off the pump for an exteneded time, gravity will drain the tank to the bottom of your discharge line. Please note, check valves fail! A 1/4 inch hole is sufficient to allow siphon break, and allow air out when the system is recharged. Just clean this hole periodically.

I'm currently setting up na new 120 and I staggered 3 holes in my return line below normal water surface to provide a siphon break, and allow air discharge.

 

[Oldschoolsalter]

Siphon break -

I know my "durso-style" stand pipe (drain to Fuge') has a siphon-break.
I thought the supply to tank also had one....perhaps not...I'll need to investigate.

However,....wouldn't water come blasting out of it?...after the air is expelled?

Also,...I find it hard to believe that much air...could be expelled through a 1/4" hole?

I have 1-1/2" PVC from basement to tank upstairs.
That's a whole lot of air!

I did install a valve after the pump..on the horizontal PVC going across the wall, on top of the Fuge',... prior to going up the run to upstairs Display tank.
I suppose I could just close it when I pull the plug for the pump.
That would prevent all the water in the line TO the tank from dropping back down to basement.

But that wouldn't happen during an unexpected power outage.

 

[stoelton]

Water will come out of it, but since it is located below the normal surface level of the water in the DT, you won't even notice it when your tank is full. Also since you have a 1 1/2 inch line, I suggest you drill 2-3 1/4 inch holes in your return line. They can be spaced an inch or two apart vertically, and this will allow sufficient area for the air to escape. it won't blast out, but it will come out relatively quickly. You don't need as much space for air since it is 800x less dense that water.

 

[jduck]

Just as I had thought would happen, did.
Massive amounts of return line air gets pushed into tank when pump has been off.
This possibly wouldn't be quite so bad, if my return wasn't so low in the tank.
But it exits my overflow box, then 90's down to about 2" off tank bottom.
Naturally, all the fish freaked when this happened!

IF I had a vertical section, on my basement plumbing, I might consider an in-line check-valve.
Unfortunately, my plumbing run really doesn't.:sad:

I know my "durso-style" stand pipe (drain to Fuge') has a siphon-break.
I thought the supply to tank also had one....perhaps not...I'll need to investigate.

However,....wouldn't water come blasting out of it?...after the air is expelled?

Also,...I find it hard to believe that much air...could be expelled through a 1/4" hole?

I have 1-1/2" PVC from basement to tank upstairs.
That's a whole lot of air!

I did install a valve after the pump..on the horizontal PVC going across the wall, on top of the Fuge',... prior to going up the run to upstairs Display tank.
I suppose I could just close it when I pull the plug for the pump.
That would prevent all the water in the line TO the tank from dropping back down to basement.

But that wouldn't happen during an unexpected power outage.

If you had a few pictures it might help some.

How is the return line plumbed?
You say that it exits overflow box then takes a 90 turn down till its 2" off bottom.
1. You can drill some siphon break holes in that 90 so air exits there. But I still feel you will get some bubbles in the tank.
2. Another option would be to remove that 90 deg and have the return flow towards the top of the tank with lock line. Bubbles would have shorter distance to travel to surface of water.
3. Because you said that the return plumbing isn't vertical you could look at a 1 1/2" Spears True Union Sch 80 ball check valve. I've seen them on ebay for about $50. Not sure how much it would restrict the flow. Didn't do that much searching on it.

I use a George Fisher Wye Check Valve on my 1 1/2" return to stop the return line from draining out. (not sure how they work installed Horizontal) My lock line returns have siphon break holes in them. I've tested it in the event of check valve failure the sump will not overflow. Its nice like you said to not have all the bubbles into the DT after the return pump shuts off for feedings/Maintenance

 

[reefone]

why does it even matter if air comes out for a second? when id turn my return pump on after it being off it would push a bunch of air into the tank for a few seconds. never bothered anything.