Herbie Overflow with Vectra DC Pump

[nashvillian]

Hello all,

First time plumbing a sump, adding a HOB overflow to existing tank. I have an eShoppes PF-1000 that comes with dual standpipes that are the same height.

Since I have a Vectra DC, where i can just set the exact GPH, can't i just tune the return to the perfect level where both pipes are silent, and still has the redundancy? I wouldn't need any gate valves then.

The tank is 65g with a 15g sump (can't move tank, its what i can fit)

 

[MaddyP]

Most of the noise from an overflow comes from the water mixing with air as it goes down the pvc. One benefit of a gate or ball valve to "tune" the overflow is it creates a back pressure which fills up the pvc.

Yes, you can certainly "tune" your DC pump to achieve the same affect as a gate valve. My DC pump is entirely responsible for keeping my display at a specific level.

 

[minorhero]

Hello all,

First time plumbing a sump, adding a HOB overflow to existing tank. I have an eShoppes PF-1000 that comes with dual standpipes that are the same height.

Since I have a Vectra DC, where i can just set the exact GPH, can't i just tune the return to the perfect level where both pipes are silent, and still has the redundancy? I wouldn't need any gate valves then.

The tank is 65g with a 15g sump (can't move tank, its what i can fit)

Short answer is no you can't.

Longer answer is that the whole point of a herbie is to have a silent overflow. The dry emergency is there for when (not if but when) your herbie fills with enough crud that it needs tuning. If you ran both with no dry emergency and both were tuned to exactly take the amount of flow your pump was returning (which is what is needed for a herbie to be silent) then when one or both filled with enough gunk (or a snail or whatever) you would have a flood.

A herbie needs a dry emergency.

 

[nashvillian]

Short answer is no you can't.

Longer answer is that the whole point of a herbie is to have a silent overflow. The dry emergency is there for when (not if but when) your herbie fills with enough crud that it needs tuning. If you ran both with no dry emergency and both were tuned to exactly take the amount of flow your pump was returning (which is what is needed for a herbie to be silent) then when one or both filled with enough gunk (or a snail or whatever) you would have a flood.

A herbie needs a dry emergency.

I get what you're saying, but the chances of both getting clogged is pretty slight. But wouldn't just adjusting the pump to create full siphon in both standpipes achieve the same effect for noise?

 

[minorhero]

I get what you're saying, but the chances of both getting clogged is pretty slight. But wouldn't just adjusting the pump to create full siphon in both standpipes achieve the same effect for noise?

If you ran both wide open you would have noise from them sucking in air. The pull of the water down the tube is strong enough to suck in a lot of air in a whirlpool effect. This why a herbie has a valve on it, to precisely tune the amount of water going down it to slow the water going down it enough that it doesn't suck in air.

So lets say you set this up. For argument sake lets say each stand pipe is taking in 500 gallons per hour for a total of 1000 gallons per hour in your system. Its tuned precisely so you are totally silent.

6 months go by, and enough biofilm has developed in one of the stand pipes that the internal diameter has shrunk a bit. Not a lot, but a bit. Its now taking in 499 gallons per hour. So your finely tuned system is now only able to take 999 gallons per hour total. But your pump is still returning 1000 gallons per hour. This means your pump is now spilling 1 gallon per hour onto your floor and will keep doing so until the sump is too low for it to take any more up. Then your pump will run dry and whatever flow in your tank will be limited to whatever wave makers etc are in your tank.

This is not a crazy situation either. With a herbie this is a 100% guarantee.

 

[nashvillian]

I was under the impression a full siphon occurred much before the maximum flow rating of the overflow.

 

[Dburr1014]

I was under the impression a full siphon occurred much before the maximum flow rating of the overflow.

A full syphone is exactly what the gate valve is for. To create a full syphone in 1 pipe. That is a lot of water when 1 pipe is a full syphone. The other pipe is for letting a trickle of water down.
The water in your tank will fluctuate. No way will it be constant. As mentioned, you have bio-film, critters, ect. That will get in besides water pressures, air pressures, all that plays in water flow. The trickling pipe allows for all that fluctuation.
But, one day you'll here your silent tank is a little noisier.
that day you may need to adjust you gate valve because food is something got in your gate and it's running slower so your 2nd pipe is now running more water and being noisy.

 

[Shirak]

I was under the impression a full siphon occurred much before the maximum flow rating of the overflow.

A 1" bulkhead with 1" ID pipe will flow almost 1000gph at full siphon.. hence the gate valve on one line so you can tune it and balance the flow.

 

[nashvillian]

But can’t I just tune it with pump flow speed?
Are you saying that a dual outlet overflow rated at 1000 GPH is going to make noise if I run my pump at 900 GPH?

 

[nashvillian]

Most of the noise from an overflow comes from the water mixing with air as it goes down the pvc. One benefit of a gate or ball valve to "tune" the overflow is it creates a back pressure which fills up the pvc.

Yes, you can certainly "tune" your DC pump to achieve the same affect as a gate valve. My DC pump is entirely responsible for keeping my display at a specific level.

Do you run gate valves on your overflow or not?

 

[Dburr1014]

But can’t I just tune it with pump flow speed?

Yes

Are you saying that a dual outlet overflow rated at 1000 GPH is going to make noise if I run my pump at 900 GPH?

Yes

 

[MaddyP]

Do you run gate valves on your overflow or not?

Yes, I have a ball valve on my drain line which I run 75% open. But I’m not running a overflow.

You might check out my build thread. It’s unlikely my setup will be applicable to you (or most anyone else’s) setup.