Header Tank?

[mogurnda]

Hi All,

I hope to expand the slug system from 4 tanks + sump to 6-7 tanks + sump this summer.  In one of Martin Moe's books, he suggests using a header tank at the top of the system to gravity feed all the rest of the tanks.  The idea is that the return feeds the header tank, and the header tank feeds everyone else, maintaining relatively constant flow to each tank when others are added or taken off line.  Seems great in principle, but there are details that I need to know more about.  Is anyone using, or has anyone used such a system?

[Origami]

I have not used such a system. But, just thinking it through from your description, Dave, it seems that what Martin's proposing is a setup where the header tank sets the overall head pressure of the lines going into the other tanks to a relatively constant level. To do this, you'd have to take the feeds off the bottom of the top tank. Neglecting friction differences in the lines from the header tank to the tanks below, the flow into each lower tank is regulated by the size of the pipe and the head pressure due to gravity. Since you're pulling from the bottom of the header tank, though, it seems that you'd have to also have an overflow in that top tank that leads directly to a sump area. This would prevent the top tank from overflowing and would set the head pressure (water column height) to a known, constant level.

 

This description may assume that the livestock tanks are all at roughly the same vertical height rather than stacked. If stacked, you'd probably have to valve down tanks at lower levels since they would have a greater effective head pressure because of the extra vertical distance relative to the header tank.

 

Of course, I'm just guessing here. Does any of that make sense?

[mogurnda]

All good thoughts, Tom.  MM did not appear to use a second overflow to prevent spills, but it seems like a very good idea.

 

He used a single vertical standpipe from the header, with valves controlling flow from the standpipe to the tanks.  Seems like I will have to restrict flow from the standpipe to the sump, so the standpipe remains filled.  The extra overflow in the header sounds especially useful in that case.

[sethsolomon]

This kinda sounds like an overflow waiting to happen to me

[Jon Lazar]

I did something this with two 55gal tanks.  One was a frag tank, and the other was a fuge.

 

A small pump moved water from the low tank to the high tank.  The high tank had an overflow back to the low tank. 

 

This was analogous to the traditional display tank and sump...you can't overflow the upper tank.

[WilRams]

I would poke around different freshwater forums for ideas as well. Many fw keepers like to have fish rooms with racks of tanks. A lot of them are sponge filtered but some systems are creative with sumps.

[Origami]

All good thoughts, Tom.  MM did not appear to use a second overflow to prevent spills, but it seems like a very good idea.

 

He used a single vertical standpipe from the header, with valves controlling flow from the standpipe to the tanks.  Seems like I will have to restrict flow from the standpipe to the sump, so the standpipe remains filled.  The extra overflow in the header sounds especially useful in that case.

Ah, of course. The standpipe is there to limit dumping of the header tank contents to the volume above the standpipe top plus the volume of the standpipe. That makes good sense. Use a manifold or multiple standpipe's in the header tank to regulate flow to the tanks.  Then, at the second level down (where the tanks are), each tank has a traditional overflow leading down to a sump. The final feature that I was describing was a traditional overflow from the header tank leading directly to the sump. It's basically a short-circuit that will protect system from a clogged standpipe. 

 

Are you needing to regulate flow through your tanks for your slug research?

[mogurnda]

 

 

This was analogous to the traditional display tank and sump...you can't overflow the upper tank.

My concern is that the  rules may get more complicated when dealing with multiple tanks on three levels.  Always good to have a safety valve.

 

I would poke around different freshwater forums for ideas as well. Many fw keepers like to have fish rooms with racks of tanks. A lot of them are sponge filtered but some systems are creative with sumps.

That is brilliant.  I seem to recall The  Krib actually had a section devoted to building fish rooms, if it's still around.

 

Ah, of course. The standpipe is there to limit dumping of the header tank contents to the volume above the standpipe top plus the volume of the standpipe. That makes good sense. Use a manifold or multiple standpipe's in the header tank to regulate flow to the tanks.  Then, at the second level down (where the tanks are), each tank has a traditional overflow leading down to a sump. The final feature that I was describing was a traditional overflow from the header tank leading directly to the sump. It's basically a short-circuit that will protect system from a clogged standpipe. 

 

Are you needing to regulate flow through your tanks for your slug research?

You are describing it just about the way I  had envisioned  it.  I am not horribly concerned about regulating the flow precisely, but I do want to maintain it steadily within the range that provides adequate turnover without saturating the overflows in the individual tanks.  

 

Right now I am using a manifold from the return, but flow pattern to all the other tanks changes if one outlet becomes overgrown and increases resistance.  Because a significant fraction of the system is, and will continue to be, devoted to growing nuisance algae, something will always get overgrown before I catch it.   With more tanks, the complexity goes up, so the header tank is intended to act as a buffer.

[mogurnda]

This kinda sounds like an overflow waiting to happen to me

That's why I am trying to find people who have made it work.  The system is in a non-lab area, and the facilities people would have my head if there was a major spill.  I do have a moisture detector on the floor that will shut off the return, just in case.

 

I'd like to argue that it was bombproof because Martin Moe used it, but he was known for spilling a lot of water.

[dpassar12]

My system is setup with multiple levels. I have three rows of tanks:

Row one,  8 foot frag drains into 8 foot frag tank, row one then drains into sump.

Row two,  3 foot frag tank drains into 8 foot frag tank which then drains into the other side of my sump.

Row three,  6 foot display tank which drains into a rubbermaid with then drains into same side of sump as frag row 2.  

 

I have 2 return pumps 4 returns on each manifold and 1 spare slot 

 

Row one, return 1 pump 1  3/4 inch full open splits with Loc-line into 2 into 8 foot frag which has 2 1.5 inch bulkheads  which drain into second frag tank 2nd frag tank has 2 1.5 inch drains which then tee into a single 1.5 inch which runs into left side of sump which has protein skimmer.  Pump 1 return 2 1/2 open 3.4 inch feeds refugium 1 which then drain into DSB which then bypasses skimmer and first layer of mechanical filtration. pump 1 return 3  3/4 inch half open pump water into rubbermaid refugium.

Row two return 4 pump 1 3/4 inch full open into 3 foot frag which has 2 1.5 inch bulkheads which then drain into 8 foot frag which has 2 1.5 inch bulkhead drains which tees into single 1.5 inch which drains into left side of sump which has no protein skimmer.

Row 3 return 1 pump 2  3/4 inch full open to display, return 2 pump 2 3/4 inch full open to display display has 4 1 inch drains which drain into rubbermaid. rubbermaid has protein skimmer and 2 1.5 inch drains which connect to single 1.5 inch line from row 2 frag system which then drain into left side of sump. Pump 2 return 3 3/4 inch 1/2 open goes to refugium 2 which drains into DSB 2 which bypasses first layer of mech filtration. 

 

So basically I have 3 head tanks one in each row which drain into lower level then all drain into single sump. Works great for me, all the drains are overkill, the flow into the lower tanks is steady, but it will only flow at the same rate as the returns that pump into the head tanks. The water from 3 rows is mixed in several places. This setup allowed me to have a single apex and a single media reactor and a single calc reactor saved me a lot of extra plumbing having tanks drain into each other. All my drains have gutter guard on them to keep the snails from getting in.  

 

I can shut off each row independent of each other. Total system vol is 120 frag 120 frag 60 frag 120 frag 180 display 100 rubbermaid fuge1 30 DSB 30 fuge 2 30 gals DSB 2 30 gals sump 40 

 

Dan

[dave w]

Maybe others have already touched on this, but my guess is that Martin Moe's header tank was meant to give equal water flow to every tank in his system, regardless of their size, which shelf they were on, or distance from the header.  

 

It's how the distribution box for septic field works.  Granted, not many people have seen this first hand.  Each drain line in the septic field is at a different elevation but all receive equal gravity feed and flow from the distribution box, which has a dozen holes at the exact same height.  When the water comes in, gravity distributes it equally to every outgoing line.

 

At least that 's what I think of when I hear of a header tank.

[mogurnda]

My system is setup with multiple levels. I have three rows of tanks:

Row one,  8 foot frag drains into 8 foot frag tank, row one then drains into sump.

Row two,  3 foot frag tank drains into 8 foot frag tank which then drains into the other side of my sump.

Row three,  6 foot display tank which drains into a rubbermaid with then drains into same side of sump as frag row 2.  

 

 

Dan

 

Wow! It took me a little while to find time to map this out.  That's room for a lot of frags!  I think my strategy will be a little different, with all the tanks in the system fed by a single manifold from the header tank.  One concern I did not mention earlier was that each tank receives the same nutrient load.  If a tank with thriving algae gets the water first, then the next one in line will get short shrift.  

 

Maybe others have already touched on this, but my guess is that Martin Moe's header tank was meant to give equal water flow to every tank in his system, regardless of their size, which shelf they were on, or distance from the header.  

 

It's how the distribution box for septic field works.  Granted, not many people have seen this first hand.  Each drain line in the septic field is at a different elevation but all receive equal gravity feed and flow from the distribution box, which has a dozen holes at the exact same height.  When the water comes in, gravity distributes it equally to every outgoing line.

 

At least that 's what I think of when I hear of a header tank.

 

I guess this approach is more common than I thought.  That is exactly the same idea, but is making me rethink the plumbing.   I had originally planned to put the valves to the tanks at the level of the individual tanks, but it might be better to approach it like the septic system and have a single manifold below the header tank.

[Origami]

I guess this approach is more common than I thought.  That is exactly the same idea, but is making me rethink the plumbing.   I had originally planned to put the valves to the tanks at the level of the individual tanks, but it might be better to approach it like the septic system and have a single manifold below the header tank.

I'm thinking that you still want to put separate valves on for each tank, Dave, if for no other reason than to be able to take a tank offline (or to add ones later on) or to curb flow to any leg as the need may dictate. The whole principle of the header tank seems to be to keep equal head pressure on each leg of the drain. This is done by isolating the pressure of the return pump from the main tanks by use of the header tank. That seems to be the whole purpose of the header tank.

[mogurnda]

I'm thinking that you still want to put separate valves on for each tank, Dave, if for no other reason than to be able to take a tank offline (or to add ones later on) or to curb flow to any leg as the need may dictate. The whole principle of the header tank seems to be to keep equal head pressure on each leg of the drain. This is done by isolating the pressure of the return pump from the main tanks by use of the header tank. That seems to be the whole purpose of the header tank.

Sorry, I wasn't clear.  There would still be a valve to each tank, but they would come off a single manifold directly under the header tank.  My original thought was to use a vertical pipe with valves at each level.  In retrospect, that does not make as much sense.