Tank Journal Archive

[192k]

• My standpipes are based on Bean Animal's design for a silent and failsafe overflow.

My first tank was exactly to his design and it worked flawlessly. I then experimented with the design and omitted some of the 90 degree elbows.

I found that if the standpipes are placed perpinducular to the rear wall (on the base of the tank/overflow) the elbows for the main syphon (99% of flow) and the emergency drain could be omitted.

I have done this modified design on my last 2 setups and it has run silently and has always started after the return pump was cycled :) It works for me and I am happy with it.

Drain 1: 32 mm slip/slip bulkhead at base of overflow - Main Syphon (99% flow)

Drain 2: 32mm slip/slip bulkhead -> Durso Standpipe that sets the height of the water inside the overflow (1% flow)

Drain 3: 32mm slip/slip bulkhead -> 32mm standpipe set just below the level of the bracing on the display tank. Emergency Drain

Drains 1 & 3 are simple.
Drain 2 involves making a durso standpipe.

Here is my take on the durso:
I follow the original design as below:
The original has extra parts that are sized differently to what I will be using.

But I make an adjustable airline intake for the end cap. It saves drilling hole after hole to find the correct size :)

Parts:
32mm endcap
1/4 John Guest Polypropylene speedfit threaded NPT 1/8 thread
1/4 John Guest 1/4 Tap
1/4 John Guest tube - cut to final length inside overflow.

Endcap sanded down and hole to suit threaded connection of JG Speedfit

Final cap assembly:

I have to now source the 32mm 90 degree elbow and 32mm t piece to complete the Durso

I have decided not to use the JG fittings and have been shown an alternative way to get an adjustable durso hole by MagicJ :)

It is much simpler and involves drilling a hole through the side of the endcap and standpipe. The endcap then is rotated to adjust the amount of air entering the tube. So simple and so effective.

 

[slin1977]

My 6mm pipe sits 10mm above the water level permanently.
That is the correct way - it acts as a siphon to make the overflow into a siphon until it turns into a surplus drain;)

 

[192k]

Thanks for posting a pic of your setup slin1977.

Yes you are correct, the durso takes over when the syphon gets blocked.

My airline will be measured and adjusted accordingly. It is just shown for illustrative purposes :) I left out the tap completely on my last build, along with the airline, and that worked well for me.

These fittings were all surplus from my PSI RO/DI unit being recommissioned again :)

 

[MagicJ]

... It saves drilling hole after hole to find the correct size :)

You can also drill a hole through the side of the end cap and through into the stand pipe - you can then rotate the end cap to make the hole size smaller if required.

Just an alternative way to create an adjustable size hole :)

 

[192k]

You can also drill a hole through the side of the end cap and through into the stand pipe - you can then rotate the end cap to make the hole size smaller if required.

Just an alternative way to create an adjustable size hole :)

That sounds like a great idea!

To adjust, just turn. I will definitely go with this way now. So much easier. Thanks MagicJ :)

I had concerns over the JG fittings being submerged anyways, as they have stainless clips that form part of the Speedfit system.

Original post updated to reflect changes

 

[MagicJ]

To adjust, just turn. I will definitely go with this way now. So much easier. Thanks MagicJ :)

Sometimes the simplest way is the best :p

 

[somethingfishy76]

Nice planning mate... I have never mastered this airline/valve method. So its scares me a bit. But if its silent its great. I look back at my old tanks and how stupidly noisy they where... we learn...

 

[192k]

Yes noise is a very important consideration for me. The hole size is not as critical when the durso is used in this configuration, as it's only taking 1% of the flow.

Because the durso is taking a small amount of flow, the amount of microbubbles entering the sump is kept to a minimum.

When the durso is used by itself, as a primary drain, the hole size in the durso becomes more critical, as it will surge if the hole is too small and gurgle if the hole is too big :) this is when noise and microbubbles become an issue.

 

[somethingfishy76]

I use two durso stand pipes and one emergency. First one is totally flooded and a valve is used to get it to go full syphon. The second then takes up the remainder, a fine tune as it will. You can set it up so that the first one is at full syphon and the second one only the smallest trickle. Dead quiet and no air pipes or valves. And when I say dead silent I mean it. Another thing I have done it do away with the whole T thing. Simply connect two 90 degree elbows together and you can even chop then for a really tight U bend. Super neat and no more towers sticking up on to of your durso's.

 

[192k]

I use two durso stand pipes and one emergency. First one is totally flooded and a valve is used to get it to go full syphon. The second then takes up the remainder, a fine tune as it will. You can set it up so that the first one is at full syphon and the second one only the smallest trickle. Dead quiet and no air pipes or valves. And when I say dead silent I mean it. Another thing I have done it do away with the whole T thing. Simply connect two 90 degree elbows together and you can even chop then for a really tight U bend. Super neat and no more towers sticking up on to of your durso's.

Yes nobody likes towering durso's :)
I am planning my external overflow at the moment and that was one issue I had - the height of the overflow determines the height of your standpipes.

 

[slin1977]

Guys , don't underestimate the importance of the emergency drain.
It is likely you will use it when you give your stand pipes a clean and reset them. Over time the flow characteristics can change on the full syphon leading to more flow through the durso.

As a syphon is more efficient at draining water than a gravity drain , my durso acts as a syphon until the actual syphon gets rid of bubbles and takes full water capacity. There after the durso takes the surplus water that the throttled back full syphon is not draining.

I intend making a comparison video between the beans version and my version on start up , but in my set up the emergency drain kicks in on start up, with my syphon/durso pipe I am left with no doubt that it is an extra fail safe that I incorporated.

 

[192k]

I am definitely running an emergency drain :)

I'll be putting valves on all the drains for the reason pointed out above - for maintenance and cleaning.

As an extra failsafe - a float switch could be incorporated in the display tank to shut off the return pump incase the emergency drain was to fail :)

 

[slin1977]

Mine is set up so sump capacity can handle power failure and complete RODI top up dump into system.

 

[192k]

Mine is set up so sump capacity can handle power failure and complete RODI top up dump into system.

Yes it is a good idea to calculate the amount of water and overflow that gets drained into the sump for a planned or unplanned power cut to the return.

The amount the display drains can be minimised by:

(1) Placement of the return lines so they are not fully submerged below the water line any more than necessary - this prevents back syphoning.

(2) Anti-syphon holes in the return line if the above is not possible.

(3) Having the syphon drain positioned so the whole overflow doesn't drain when the return pump is cut off. A simple pipe on the syphon can do this.

 

[slin1977]

And to add to the discussion , my standpipes in the coast to coast when removed from the coast to coast , the sump can handle the volume. These are not glued in as are a few unglued pipes along the way.
Bear in mind I have a very small but calculated sump.

 

[somethingfishy76]

Great point here fellas. My back boxes positioned lower so that the middle of the highest durso will be in the middle of the holes ov the tank. That way no big drops of water for nice and quiet tank. Diference between the two durso's is only enough to flood the first one and the second take up the slack. 3/4 lock line with duck bills will be placed to be level with the water and will break suction instantly when the pump stops. So minimum water back from the durso's and very little to none from the duck bills.

Yes my systems always allow for all water and RO to be drained into it safely. This is something many people don't think of but sure do learn quickly.

Emergency drain will be the third pipe.

 

[slin1977]

Great point here fellas. My back boxes positioned lower so that the middle of the highest durso will be in the middle of the holes ov the tank. That way no big drops of water for nice and quiet tank. Diference between the two durso's is only enough to flood the first one and the second take up the slack. 3/4 lock line with duck bills will be placed to be level with the water and will break suction instantly when the pump stops. So minimum water back from the durso's and very little to none from the duck bills.

Yes my systems always allow for all water and RO to be drained into it safely. This is something many people don't think of but sure do learn quickly.

Emergency drain will be the third pipe.

Great design tactics mate. These things should be considered as fail safe measures both at home , work or on holiday.