Please help with drain/return ideas and calculations

[FortuneFavours]

Hi all

I need some advice on how to set up the drains and return for my 300G tank.

The tank has two bulkheads (on the bottom pane of glass) that take 32mm pipes (I think that's 1.25"). I want to find a way of having good flow that is as quiet and safe as possible.


CALCULATED WATER VOLUME?
One of the first questions I have is about safety in terms of flooding the sump: do you calculate a fixed amount of water that needs to be in the system? For example, one of my first thoughts was to just have two pipes set at a specified depth below the water level.

My tank is 5ft x 30" x 39" (300 gallons)
My sump is 4ft x 20" x 18" (75 gallons)

So if I set my drain pipes at 3" below the water height that I want, the maximum that could drain down to the sump is 23 gallons. This is equivalent to roughly 5.5" of water in the sump.

So if set the water level in my display tank to 3" above the drain pipes and filled my sump with 10" of water (about 40 gallons), would that be safe? My logic(?) being that only another 23 gallons could possibly fill the sump, raising the water level in the sump from 10" to about 15.5" (leaving a couple of inches to spare as the sump is 18" high).


NOISE REDUCTION?
I've read all about the annoying gurgling noises that normal standpipes can make.

I've read a little about the Durso / Herbie methods and it seems like people prefer the Herbie method because it's quieter. The problem I have with the Herbie method is, if I've understood correctly, the main drain pipe that has the full syphon is supposed to be about 6" below the emergency standpipe. But doesn't this increase the risk of flooding the sump, i.e. wouldn't the water from the DT drain down to the level of the lowest pipe if the the emergency pipe became blocked for any reason?

Has anyone ever used one of these bottle-traps and would they achieve a quieter drain?


RETURN IDEAS
I was just going to have a standard return pipe (over the back of the tank) set just below the water line, so there would be minimal back syphon in the event of a power failure. I'll build in a syphon break too - although, being a newbie and not quite understanding how it all works, I'm not sure how much faith I should put into a syphon break?

Which brings me on to my idea: I will be building a support framework using PVC pipes for my rockwork (I'll be dry-scaping using base rock) and I had the idea to have the return feed into the PVC support frames (I would use end caps and drill small holes in the PVC pipes). This would mean the water coming up from the sump would flow through the PVC framework that is supporting the rocks and thus helping to remove dead spots, at least in some ares (depending on the amount of flow I can achieve).

I have a couple of questions:

1. Would the flow from through this pipework bother critters/corals, etc?

2. I know this significantly increases the amount of water that might back-syphon into the sump if the return pump fails for whatever reason; would a syphon-break + non-return valve(s) be sufficient to stop this happening?


I hope my questions make sense!

Looking forward to your responses.

 

[RocketEngineer]

Do you have an overflow box? If not you should add one. The bigger the better. Even a single pane of glass would work but the longer the edge the better the surface skimming.

With the overflow box installed, the amount of water that drains from the system is limited by the height of the box and how low in the box the standpipes are. I recommend no more than about 1" below the water level of the display so that you minimize noise from water coming over the edge of the overflow box. In your case with two holes already present I would go with a Herbie setup of a siphon and dry emergency. These can be simple vertical pieces of pipe in the box with the valve for the siphon under the tank. The siphon drain should exit into the sump no more than 1" below the water in the sump when everything is up and running. This will minimize the noise but still allow the siphon to purge on startup.

If the outlet is right at the water surface, you don't need a "siphon break" as the return will pull air almost immediately. I put no faith that a small hole won't get clogged over time so the returns at the surface is the only totally fail safe method of minimizing return back flow.

Don't connect the returns to the rock work frames. The inside of the pipes provides places for things to grow where fish can't get to them (pods, sponges and tube worms come to mind). Plus if you want to change your rocks around you don't want to be dealing with cutting plumbing in order to change things around.

 

[wolfblue]

Syphon breaks work but they must be maintained. I like to leave a piece of wire hanging from a length of fishing line back there. Every week or so when you think about it poke it through the hole.

 

[FortuneFavours]

Do you have an overflow box? If not you should add one. The bigger the better. Even a single pane of glass would work but the longer the edge the better the surface skimming.

With the overflow box installed, the amount of water that drains from the system is limited by the height of the box and how low in the box the standpipes are. I recommend no more than about 1" below the water level of the display so that you minimize noise from water coming over the edge of the overflow box. In your case with two holes already present I would go with a Herbie setup of a siphon and dry emergency. These can be simple vertical pieces of pipe in the box with the valve for the siphon under the tank. The siphon drain should exit into the sump no more than 1" below the water in the sump when everything is up and running. This will minimize the noise but still allow the siphon to purge on startup.

If the outlet is right at the water surface, you don't need a "siphon break" as the return will pull air almost immediately. I put no faith that a small hole won't get clogged over time so the returns at the surface is the only totally fail safe method of minimizing return back flow.

Don't connect the returns to the rock work frames. The inside of the pipes provides places for things to grow where fish can't get to them (pods, sponges and tube worms come to mind). Plus if you want to change your rocks around you don't want to be dealing with cutting plumbing in order to change things around.

Ah, now it makes sense (I think):

I will have an internal overflow box. Both bulkheads are in one corner, and as the tank will now be used as a room divider (it wasn't previously, hence the bulkheads being in a corner) there will be one rectangular overflow box which will have three sides that water can flow over - approx 10" x 5" x 10". The other 'side' will be the back of the tank, of course.

The tank is 39" (1m) tall and if the water level will be about 3" below that, we're looking at a water level of around 36" in the DT.

Assuming the top of the overflow box is just slightly below the water level and the main syphon drain is 6" below the water line, then less than 1 gallon of water can flow into the sump if no further water is added to the DT (6" of water inside a 10" x 5" overflow box - that's not even taking into account the fact that most of the available volume will be used up by the two drain pipes).

Is that right?

Noob question: what are the benefits of surface skimming?

I think having the return at the surface is definitely the safest bet.

Syphon breaks work but they must be maintained. I like to leave a piece of wire hanging from a length of fishing line back there. Every week or so when you think about it poke it through the hole.

I wouldn't trust myself to remember to check the syphon hole! And I think I should change my handle to ParanoidByNature.

 

[RocketEngineer]

So you are looking at 25" of overflow edge which isn't too bad considering the options. I always work with the assumption that 1" of display tank height will drain into my sump which should be more than it would take for the returns to suck air.

Have you ever seen the sheen on a pond or puddle where oils have gathered on the surface? The same thing happens in a tank and this "oil slick" can become problematic. By having the overflow pull from the water surface, the oils get pulled out of the display and into the sump where the skimmer removes them out of the water. The oils are what form the foam in the skimmer so to get maximum removal via the skimmer you want to be pulling only the very top layer of water out of the tank and into the sump.

 

[FortuneFavours]

So you are looking at 25" of overflow edge which isn't too bad considering the options. I always work with the assumption that 1" of display tank height will drain into my sump which should be more than it would take for the returns to suck air.

Have you ever seen the sheen on a pond or puddle where oils have gathered on the surface? The same thing happens in a tank and this "oil slick" can become problematic. By having the overflow pull from the water surface, the oils get pulled out of the display and into the sump where the skimmer removes them out of the water. The oils are what form the foam in the skimmer so to get maximum removal via the skimmer you want to be pulling only the very top layer of water out of the tank and into the sump.

Makes perfect sense now - thank you!

Any thoughts on the bottle traps that I linked to above? I've never seen anyone use them on an aquarium (perhaps with good reason) - I wonder if they really do eliminate the "gurgle"? Might buy one just to experiment. Don't really understand how they work though; isn't the 'gurgling' noise at the top of the standpipe and not down at trap level? I suppose in normal domestic use that distance is a lot shorter?

 

[RocketEngineer]

The gurgle comes from using an air/water drain system. Using a Herbie you don't have to worry about it because you have one drain full of water and the other one totally empty.

 

[FortuneFavours]

The gurgle comes from using an air/water drain system. Using a Herbie you don't have to worry about it because you have one drain full of water and the other one totally empty.

So I've had (nearly) everything I need for my pipework delivered and hope to make a start tomorrow. I've also been reading about the Herbie drain method.

I have some questions though:

Q1. The two bulkheads I have are 1" and I do have 1" pipe, but I remember reading somewhere (honestly can't remember where) that it's better to have pipe that is bigger than the bulkhead size and use a reducer? I can't remember why they suggested that, but does that make sense to anyone?

Q2. Should I set the emergency drain slightly below or above the water level in the overflow box?

Q3. As the bulkheads are only 1" and one will be used for the emergency drain, will there be enough flow for a 300G tank?

Q4. I will be purchasing a Jebao DC12000 return pump. Anyone have any idea what size pipe to use for the return?

Thanks

 

[JMorris271]

So I've had (nearly) everything I need for my pipework delivered and hope to make a start tomorrow. I've also been reading about the Herbie drain method.

I have some questions though:

Q1. The two bulkheads I have are 1" and I do have 1" pipe, but I remember reading somewhere (honestly can't remember where) that it's better to have pipe that is bigger than the bulkhead size and use a reducer? I can't remember why they suggested that, but does that make sense to anyone?

Using the larger size pipe for the emergency is speaking of if there are two different sized pipes; say 3/4"and 1". You would use the 1" as the emergency drain and the 3/4 as the full siphon. A reducer would be for the event of say two 1" bulkheads and you choose to reduce the size of the full siphon the 3/4 "
The larger the diameter of the emergency drain, the finer and spread out the sheet of water will be that runs down the interior of the pipe would make it more silent. That's what I have read

Q2. Should I set the emergency drain slightly below or above the water level in the overflow box?

What I understand is about 1/8 inch below the bottom of the weir openings

Q3. As the bulkheads are only 1" and one will be used for the emergency drain, will there be enough flow for a 300G tank?
It depends on the amount of head loss on your setup Add it all up and check out what your pump is rated for at that amount of head.

Q4. I will be purchasing a Jebao DC12000 return pump. Anyone have any idea what size pipe to use for the return?
I don't know. My guess is .75 to 1"

Sounds like it will be a wonderful tank

Thanks

Cheers

 

[JammyBirch]

Doesn't make any sense to me why the pipe would need to be larger than the bulkhead, the max volumetric flow will be determined by the smallest fitting ID.

Anyway, it sounds like you are well on your way to having a bullet proof system. If you have an emergency drain you are protected from a clogged main drain. The other problem you need to prepare for is a power outage. In this case you return pump is dead, and all of the water that is above your overflow will end up in your sump.

Make sure you calculate this volume so that you can setup your sump water level correctly to hold it all.

Totally mess free...your ATO is the only wrench in the works. I use a smart ATO that uses a laser sensor, works awesome and will stop automatically if it dispenses more than the normal amount of water.

I'm pretty big on not having an overflow, or at least my wife tells me to be. Good luck and post some pics as you progress.

 

[FortuneFavours]

Thanks for the response JMorris271. I eventually found the info on the DC12000 - it takes 1.5".

Doesn't make any sense to me why the pipe would need to be larger than the bulkhead, the max volumetric flow will be determined by the smallest fitting ID.

I think, as JMorris271 mentioned, it's something to do with having an even quieter emergency drain. Don't understand the physics of it myself, but do remember reading it in a couple of places.

I'm pretty big on not having an overflow, or at least my wife tells me to be.

I would love to not have an overflow - it will be a particular eyesore in my tank; it's a used tank which has the bulkheads in one corner, but I'm going to be using that tank as a room divider so they're not ideally located!

I started this thread planning not to have an overflow (hence the calcs in my first post), but I don't think I could live with a noisy sump. The Herbie drain is supposed to be super silent, so I'm hoping it will be worth the trade off.

 

[FortuneFavours]

Hi all

So I spent half the day yesterday putting together an overflow box and starting the pipework for the herbie overflow, but I've changed my mind!

The overflow box is really unsightly, given the fact that the tank will be a room divider, and it's going to be almost impossible to clean the box or the glass near it. The (rather shoddily patched up) euro-bracing also gets in the way, so I can't even reach into the box.



So I've decided to lose the overflow box altogether and run the pipework for the herbie to the back of the tank so it doesn't look so bad. (There are a few things I probably could do, such as drill new holes for the drains in the right place, but I really don't want to drill any more holes.)

The bottom of the strainer for the main siphon drain will only be 3" below the emergency drain. I know it's supposed to be at least 6 inches so the siphon starts again quickly, but any more than 3" will end up flooding my sump if there's a problem with the return pump.

I'm aware that this means I'll lose the benefits of surface skimming, but I think I'll have to live with it. The emergency drain will hopefully give me a small amount of surface skimming.

With this in mind, could someone check the calculations in my first post on this thread (ignore the rest of the post) and just let me know if there's anything else I need to consider?

Is it difficult to stabilise the water level in a display tank without having an overflow? I still haven't quite got my head round all this yet.

Thanks

 

[FortuneFavours]

Hi all

So I finally reworked the plumbing for the drains and, although the risk is now a lot greater with no overflow box, it looks a lot better. Here's a pic (also showing the beginnings of my dry-scaping!):



The main siphon drain is supposed to be 6 inches below the emergency drain so the full siphon restarts properly, but I just can't afford to do that with this setup - it's too much water for my sump.

 

[RocketEngineer]

Not to change your plans but have you ever considered a "floating" overflow box? Think of the two riser tubes come into the bottom of an acrylic box via bulkheads with everything glued on the tank side. Inside the box would be the stand pipes which aren't glued into the bulkheads. That way you get rid of the huge box but keep the surface skimming which is the entire point of an overflow.

 

[FortuneFavours]

Not to change your plans but have you ever considered a "floating" overflow box? Think of the two riser tubes come into the bottom of an acrylic box via bulkheads with everything glued on the tank side. Inside the box would be the stand pipes which aren't glued into the bulkheads. That way you get rid of the huge box but keep the surface skimming which is the entire point of an overflow.

I really like that idea, but it might be a bit late for me now that I've glued in the drain pipework! If it wasn't for the eurobracing getting in the way, I could have made an acrylic box and slipped it over the drains... Ah well, suppose I'll just have to live with it now. Shame I didn't post here earlier!!!

 

[RocketEngineer]

It can still be done.

Cut off the pipes at the exact same height above the bottom of the tank, put the nuts over the pipes, put the box over the pipes, place the gasket over the pipe, glue the bulkheads in, raise the box and gaskets up under the flange of the bulkhead, bring the nut up and tighten.

 

[SGT_York]

Overflow is a huge deal.

Surface skimming removes the scum or oily gloss on the water. The gloss prevents air exchanges decreases PH, affects temperature, and greatly reduces water quality due to nitrate and phosphate materials floating and not reaching the skimmer. An overflow box is a must if you want good looking corals. I highly recommend following rocket engineer's advice.

 

[FortuneFavours]

It can still be done.

Cut off the pipes at the exact same height above the bottom of the tank, put the nuts over the pipes, put the box over the pipes, place the gasket over the pipe, glue the bulkheads in, raise the box and gaskets up under the flange of the bulkhead, bring the nut up and tighten.

Ah, now that is a good idea - no wonder you're a rocket engineer!!! I will try and give this a go, thank you. Assuming the box I make has watertight seams then this will solve my 'main drain needs to be 6" below the emergency drain' problem too.

...I highly recommend following rocket engineer's advice.

Yes, RocketEngineer has been super helpful so far. :thumbsup:

 

[FortuneFavours]

I have a question: I'm going to be using an external protein skimmer, so instead of having an overflow box in the display, couldn't I have one in the sump (to feed the protein skimmer)?

 

[RocketEngineer]

It won't do anything for you because the purpose of the overflow is to pull the oils/proteins that collect on the tank surface into the sump so the skimmer can remove them. Having one in the sump doesn't gain you anything and not having one in the tank will mean they can still collect on the water surface and lead to an oil slick on the display.