Herbies silent overflow

[BeanAnimal]

The proper way to setup an overflow like this is to have 3 standpipes. 1 At full siphon, choked down with a ball valve to force some flow into the second standpipe. The 3rd standpipe is the emergency.

This can be done with 2 standpipes (as mentioned above) the emergencey standpipe will handle part of the overall flow ALL THE TIME. This is a horrible setup with regards to disaster, unless the emergency standpipe itself can handle the entire flow of the return pump with the primary standpipe closed off. In other words when possible use 3 standpipes (2 for balancing flow and the 3rd for emergency).

A downturned elbow on the primary standpipe will help prevent a will help prevent a vortex and will certainly aid in level adjustments.

Simply close down the valve until a decent flow of water is forced into the secondary (or in this case emegcenyc) standpipe. This flow (in the secondary) should not be so much that it draws air along with it. It should cascade down the seconadry and create no bubbles. The primary will be under full siphon all the time and should create NO bubbles either.

Bean

 

[derick75]

unless you drill your tank yourself few people are going to have 3 standpipes. My emergency drain handles all flow effortlessy. I removed the drain and just used the bulkhead as the drain and used a plastic strainer in the bulkhead , yet my return is full of microbubbles, this method (removing the drain standpipe)made it worse

 

[jayo]

bean, I agree that it is very important that the emergency drain is able to handle all the water flow if necessary. I see no reason for a third standpipe.

jayo

 

[kimoyo]

I only have two and am not worried at all. The two standpipes are at different heights. So I have the water under the backup pipe but not low enough to draw bubbles into the first pipe and have no need for an elbow.

Both my pipes are the same size piping but if your emergency is smaller just have a return pump where the emergency can handle all its flow.

 

[BeanAnimal]

Primary standpipe runs under full siphon
Secondary standpipe runs at partial flow
emergency standpipe stays dry


For a flood, at least 2 standpipes would have to be fully blocked with a 3rd being partially blocked. The primary is already mostly blocked anyway. Critters and algea grown in standpipes that run water but are open to air. In a 2 standpipe balanced siphon/freeflow system, this put the "emergency" standpipe in a MUCH greater danger of becoming partialy clogged and cuasing a flood.

Moreover, it is MUCH easier (and quieter) to balance a system with down turned elbows. A secondary standpipe with a downturned elbow and an small air vent will be dead silent. The air vent prevents a siphon from ever being drawn and the down turned elbow prevents any of the cascading water noise from leaking.

Of course you can use 2 standpipes as long as the emergency can handle 100% of the flow with a decent amount of headroom. I prefer at least 3 standpipes. They system is easier to balance, more quiet (if it matters), and gives me more piece of mind.

 

[BeanAnimal]

The down turned intake prevents a vortex from being formed. Depending on your flow rate and pipe size you can get away without it.

Kimoyo, if you have no water running through the secondary pipe, then you are relying on the siphon alone to balance the system. This will eventually fail (and in most cases is not possible to get balanced in the first place). In a truley balanced system the siphon is only handling about 75% of the flow. In that way, the flow would have to drasticaly change to "unbalance" the system and cause the secondary to siphon (causing flushing) or the primary to draw air. In other words by splitting the flow between a siphon and a free flow model, the overall balance can sway somewhat in either direction before air is drawn into the system. With a 100% siphon and NO free flow counterpart, the system is very easily broken by a small change in flow.

 

[derick75]

so my sump has no bubbles and is dead silent with this method which is great, i just plumbed my return line again new hose and glued some 90s to over the tank... but still getting alot of micobubbles from the return

 

[BeanAnimal]

So you are putting micro bubbles back into the tank, but they are not coming from the overlow. This means you have a leak in your return pump plumbing or pump seals -OR- you have a cavitation problem.

 

[derick75]

no leak in the return line i just tried 2 diffrent hoses. and my 90s are glued air tight, i dont see any vortec in the water and i am not sure how to check for a bad seal in the mag7 , i removed the ball valve and the check valve from the return line to eliminate cavitation problems....so i need to eliminate a seal issue within the pump?

 

[BeanAnimal]

IF you are 100% sure that there is no way the elbows are leaking. Many leaks are too small to drip water, but large enough to suck in air when the system is running. The same holds true for the seal on the front of the mag. You could be leaking air at the hose connection to the mag possibly. You can remove the front cover of the mage and inspect the gasket. You can use silicone GREASE (not sealant) to apply over the gasket if you wish.

Your sure there are no bubbles in the sump?

 

[derick75]

i run the drain about 2 inches under water in the sump. I dont see any bubbles coming out. I also use a filter sock as well. I can not see and bubbles in the sump at all. The sump is very quiet no currrent. where my hose connects to the mag7 via the hosebarb..well that is under water as well. so i dont know..it is a strady flow of microbubbles.

 

[derick75]

as far as the seal goes the mag is underwater so how can air be sucked in?

 

[BeanAnimal]

I was not aware you were running it internal.

If you can not see any bubbles in the sump then...
The bubbles are either coming from a joint that is exposed and leaking, or from cavitation in the pump volute.

Bean

 

[crumbletop]

Bean -- he has bubbles even if he doesn't have the sump on. Bubbles are coming out of all of his powerheads even when running only the powerheads for 15 hours. At least, that is my understanding...

 

[BeanAnimal]

I didn't read the whole thread... maybe I should have.

You will simply need to find the source by a process of elimination.