Water volume expansion reservoir?

[Erasmus Crowley]

I've been thinking about an idea for a plumbing design that I don't think I've ever seen anyone try before. I don't know if I'm actually ever going to attempt it myself, but I'm really tempted to. I thought that I would bring it up for discussion and see if anyone can see any disadvantages that I don't see yet.

The purpose of all of this would be to increase water parameter stability and provide a buffer to protect against nutrient spikes or fluctuations in PH and/or water chemistry.

In my head, here's how it would work. It starts from the overflow from the display tank. Instead of dropping the water down into the sump, it gets rerouted to an external reservoir of saltwater. The reservoir has a simple overflow pipe inside, and when it is full then the excess water is then routed back to the sump to be heated and filtered as usual. That's it.

If I were to implement it, I would probably build a pretty looking box to hold a 50gallon water barrel. I would definitely insulate the inside of the box to retain heat and silence any water noises. I'd also try to keep the barrel as sealed as possible, with an exception of a tiny air exchange hole to allow pressure changes inside the barrel.

Since I run a 40g display, and a 20g sump, this would instantly double my water volume in the system. The effect on heating energy and evaporation would be negligible since the barrel would be sealed and insulated. Once it's set up, you can just forget that it exists for years at a time because it's just a barrel full of water with no moving parts. Doing this seems like it could cut my PH fluctuations from the day/night cycle in half, and also dramatically increase the chances for my livestock to survive a large fish dying and spiking ammonia by allowing for more volume to dilute the ammonia that gets produced. If a person were so inclined, they could even drop a few pieces of dry rock in the bottom of the barrel to grow some sponges and act as an cryptic refugium.

Has anyone done this before? Would there be any disadvantages if someone did?

 

[mike550]

@Erasmus Crowley so this is just a way of increasing overall water volume — sort of reminds me of a cistern.

A few random thoughts. First would it make more sense to put this tank on the return side so the tank water has already run through your mechanical filter and skimmer? Just thinking it would be cleaner. Second, how will you maintain flow in the barrel so the entire 100G of your system is consistent - thinking chemistry and temperature. Third, it’s an interesting idea in terms of stability. Go for it

 

[TheBear78]

Sounds plausible and the overflow system would maintain flow just as a normal sump and return pump does.

put this tank on the return side so the tank water has already run through your mechanical filter

Logical but it would need to be a sealed container?

 

[Passenger]

I think most people just upgrade to a larger display and sump lol

 

[srobertb]

I've been thinking about an idea for a plumbing design that I don't think I've ever seen anyone try before. I don't know if I'm actually ever going to attempt it myself, but I'm really tempted to. I thought that I would bring it up for discussion and see if anyone can see any disadvantages that I don't see yet.

The purpose of all of this would be to increase water parameter stability and provide a buffer to protect against nutrient spikes or fluctuations in PH and/or water chemistry.

In my head, here's how it would work. It starts from the overflow from the display tank. Instead of dropping the water down into the sump, it gets rerouted to an external reservoir of saltwater. The reservoir has a simple overflow pipe inside, and when it is full then the excess water is then routed back to the sump to be heated and filtered as usual. That's it.

If I were to implement it, I would probably build a pretty looking box to hold a 50gallon water barrel. I would definitely insulate the inside of the box to retain heat and silence any water noises. I'd also try to keep the barrel as sealed as possible, with an exception of a tiny air exchange hole to allow pressure changes inside the barrel.

Since I run a 40g display, and a 20g sump, this would instantly double my water volume in the system. The effect on heating energy and evaporation would be negligible since the barrel would be sealed and insulated. Once it's set up, you can just forget that it exists for years at a time because it's just a barrel full of water with no moving parts. Doing this seems like it could cut my PH fluctuations from the day/night cycle in half, and also dramatically increase the chances for my livestock to survive a large fish dying and spiking ammonia by allowing for more volume to dilute the ammonia that gets produced. If a person were so inclined, they could even drop a few pieces of dry rock in the bottom of the barrel to grow some sponges and act as an cryptic refugium.

Has anyone done this before? Would there be any disadvantages if someone did?

I mean…we’re all doing it in a way.

It’s just to increase water volume. Look at the people with room- they’re running 2, 300gal stock tanks on a 250g display. Volume is the key here. We all want it. Not all of us have the space or spouse willing to let us reroute 1.5” water lines through their living room.

Space “just for water” isn’t a luxury many of us have but if you have it, use it! I’d use a 50-100g standing water tank. Black it out. Uniseals. There’s no flow in there and to quote a saltwater legend: “water is lazy” so you’ll need a powerhead or you’ll have a mud bed in there in 6 months. As always, more complexity leads to more points of failure. I would plumb it off my sump personally and I’d aim for 10x flow. The water isn’t benefitting from just sitting in there doing nothing. It’s supposed to dilute nutrients so it needs to get circulated.

I’d need to add 20% volume MINIMUM or it wouldn’t be worth it to me personally.

 

[Erasmus Crowley]

@Erasmus Crowley so this is just a way of increasing overall water volume — sort of reminds me of a cistern.

A few random thoughts. First would it make more sense to put this tank on the return side so the tank water has already run through your mechanical filter and skimmer? Just thinking it would be cleaner. Second, how will you maintain flow in the barrel so the entire 100G of your system is consistent - thinking chemistry and temperature. Third, it’s an interesting idea in terms of stability. Go for it

I feel like putting the reservoir on the return side would make the plumbing more complicated. I think it could be done if the reservoir was completely sealed and it acted as a ridiculously large canister filter, but then the whole thing would be pressurized so I'd have to pay a lot more attention to making sure the plumbing is done well so it didn't leak. Doable though.

In defense of putting it on the overflow side though, if the plumbing were done in a specific way then it could act as a septic tank to 'digest' the waste and debris into nutrients that can be pulled out by a refugium.

I'm not sure which way would ultimately be better for the system.

I think most people just upgrade to a larger display and sump lol

A larger display means more livestock, more food, more dosing, bigger fish, brighter lights for more penetration into the deeper tank. All of that adds up to bigger swings in chemistry and PH. Bigger livestock means bigger ammonia spikes when it dies and the corpse gets lost behind a rock or something.

Adding a reservoir like I described would allow me to slow those changes and buffer against disasters without all the extra inputs and risks of a bigger display with more and larger animals.

Or, to put it another way "Why not both?". A person could definitely upgrade to a 100 gallon display with a 40 gallon sump if they wanted to have extra livestock, but also plumb in a 100 gallon reservoir system for a total of 240 gallons. Surely 240 total gallons is more stable than 140 gallons.

 

[srobertb]

I feel like putting the reservoir on the return side would make the plumbing more complicated. I think it could be done if the reservoir was completely sealed and it acted as a ridiculously large canister filter, but then the whole thing would be pressurized so I'd have to pay a lot more attention to making sure the plumbing is done well so it didn't leak. Doable though.

In defense of putting it on the overflow side though, if the plumbing were done in a specific way then it could act as a septic tank to 'digest' the waste and debris into nutrients that can be pulled out by a refugium.

I'm not sure which way would ultimately be better for the system.



A larger display means more livestock, more food, more dosing, bigger fish, brighter lights for more penetration into the deeper tank. All of that adds up to bigger swings in chemistry and PH. Bigger livestock means bigger ammonia spikes when it dies and the corpse gets lost behind a rock or something.

Adding a reservoir like I described would allow me to slow those changes and buffer against disasters without all the extra inputs and risks of a bigger display with more and larger animals.

Or, to put it another way "Why not both?". A person could definitely upgrade to a 100 gallon display with a 40 gallon sump if they wanted to have extra livestock, but also plumb in a 100 gallon reservoir system for a total of 240 gallons. Surely 240 total gallons is more stable than 140 gallons.

This is a want vs reality. We all want it. We all want more volume.
In fact I’ve already come up with a plan (which I will name after you- “Erasmus Tank”). But I have a 3,000sq ft unfinished basement where I can put down some cinderblocks, toss a 100g tank down, and plumb it in. Most people dont.

 

[fish farmer]

I feel like putting the reservoir on the return side would make the plumbing more complicated. I think it could be done if the reservoir was completely sealed and it acted as a ridiculously large canister filter, but then the whole thing would be pressurized so I'd have to pay a lot more attention to making sure the plumbing is done well so it didn't leak. Doable though.

In defense of putting it on the overflow side though, if the plumbing were done in a specific way then it could act as a septic tank to 'digest' the waste and debris into nutrients that can be pulled out by a refugium.

I'm not sure which way would ultimately be better for the system.



A larger display means more livestock, more food, more dosing, bigger fish, brighter lights for more penetration into the deeper tank. All of that adds up to bigger swings in chemistry and PH. Bigger livestock means bigger ammonia spikes when it dies and the corpse gets lost behind a rock or something.

Adding a reservoir like I described would allow me to slow those changes and buffer against disasters without all the extra inputs and risks of a bigger display with more and larger animals.

Or, to put it another way "Why not both?". A person could definitely upgrade to a 100 gallon display with a 40 gallon sump if they wanted to have extra livestock, but also plumb in a 100 gallon reservoir system for a total of 240 gallons. Surely 240 total gallons is more stable than 140 gallons.

How is this different than a small DT with a huge sump?

Just because someone has a large tank doesn't mean they will or should stuff it with too much stock.

 

[srobertb]

How is this different than a small DT with a huge sump?

Just because someone has a large tank doesn't mean they will or should stuff it with too much stock.

It’s…exactly like that. Many of us have a display, equipment, refugium, and frag tank plumbed together. It’s just a single-purpose tank to add volume vs dual purpose (volume+filtration).

When I lived next to the bay in North Carolina I thought about just plumbing water in from my backyard, passing it thru a UV, socks, and a heater. The world would have been my refugium!!!!!

 

[Erasmus Crowley]

This is a want vs reality. We all want it. We all want more volume.
In fact I’ve already come up with a plan (which I will name after you- “Erasmus Tank”). But I have a 3,000sq ft unfinished basement where I can put down some cinderblocks, toss a 100g tank down, and plumb it in. Most people dont.

True. It'd definitely be several hundred dollars for the water tank and materials to pull it off in my relatively small system. I can't shake the feeling that it would be worth it though, especially compared to the amount of money that I've invested in stuff like lights and controllers. But it's obviously not necessary.

An "Erasmus Tank".
That's incredibly amusing and I love it.

How is this different than a small DT with a huge sump?

Just because someone has a large tank doesn't mean they will or should stuff it with too much stock.

For one, I don't have space in my stand for a larger sump. But also, a sump is often open at the top and exposed to air. This allows for extra evaporation (with all the minor inconveniences that come with it) and it requires extra heating because it's not usually insulated. A sealed and insulated reservoir allows me to increase my water volume and stability with (theoretically) no extra maintanance work or ongoing costs.

 

[srobertb]

True. It'd definitely be several hundred dollars for the water tank and materials to pull it off in my relatively small system. I can't shake the feeling that it would be worth it though, especially compared to the amount of money that I've invested in stuff like lights and controllers. But it's obviously not necessary.

An "Erasmus Tank".
That's incredibly amusing and I love it.




For one, I don't have space in my stand for a larger sump. But also, a sump is often open at the top and exposed to air. This allows for extra evaporation (with all the minor inconveniences that come with it) and it requires extra heating because it's not usually insulated. A sealed and insulated reservoir allows me to increase my water volume and stability with (theoretically) no extra maintanance work or cost.

If I have a nitrate problem or get bored, I’m trying this. Not to be a jerk, but the thought has crossed my mind. I just got done building my fish room and am still working on that stuff so more concrete and plumbing doesn’t sound like fun right now. But new fish tanks are like children: After you get one another one sounds like a horrible idea for at least 3 years.

 

[ScottB]

Two things.

Warm water rises and cold sinks. I would incorporate a circulation pump of some kind. Otherwise the water won't really mix. The (warm) overflow water will just flow out the top of the reservoir.

The pump circulation pump may help with this, but the second aspect to consider is settling detritus. Either keep it suspended or make the reservoir easy to service/vacuum.

Send it!

 

[Fish Styx]

I've been thinking about an idea for a plumbing design that I don't think I've ever seen anyone try before. I don't know if I'm actually ever going to attempt it myself, but I'm really tempted to. I thought that I would bring it up for discussion and see if anyone can see any disadvantages that I don't see yet.

The purpose of all of this would be to increase water parameter stability and provide a buffer to protect against nutrient spikes or fluctuations in PH and/or water chemistry.

In my head, here's how it would work. It starts from the overflow from the display tank. Instead of dropping the water down into the sump, it gets rerouted to an external reservoir of saltwater. The reservoir has a simple overflow pipe inside, and when it is full then the excess water is then routed back to the sump to be heated and filtered as usual. That's it.

If I were to implement it, I would probably build a pretty looking box to hold a 50gallon water barrel. I would definitely insulate the inside of the box to retain heat and silence any water noises. I'd also try to keep the barrel as sealed as possible, with an exception of a tiny air exchange hole to allow pressure changes inside the barrel.

Since I run a 40g display, and a 20g sump, this would instantly double my water volume in the system. The effect on heating energy and evaporation would be negligible since the barrel would be sealed and insulated. Once it's set up, you can just forget that it exists for years at a time because it's just a barrel full of water with no moving parts. Doing this seems like it could cut my PH fluctuations from the day/night cycle in half, and also dramatically increase the chances for my livestock to survive a large fish dying and spiking ammonia by allowing for more volume to dilute the ammonia that gets produced. If a person were so inclined, they could even drop a few pieces of dry rock in the bottom of the barrel to grow some sponges and act as an cryptic refugium.

Has anyone done this before? Would there be any disadvantages if someone did?

I did something like this years ago. I plumbed a 40 gallon breeder into the system from a manifold off the return to add additional volume. I kept a heater and powerhead in there. When it was time to do water changes, I turned off flow to that tank, drained it, and mixed the SW in there. When it was ready, I flipped the valves and let it flow back into the water column.

 

[Erasmus Crowley]

Two things.

Warm water rises and cold sinks. I would incorporate a circulation pump of some kind. Otherwise the water won't really mix. The (warm) overflow water will just flow out the top of the reservoir.

The pump circulation pump may help with this, but the second aspect to consider is settling detritus. Either keep it suspended or make the reservoir easy to service/vacuum.

Send it!

You could possibly remedy the temp mixing problem by using a pipe inside the reservoir to insert the water at the bottom and then remove the water with an overflow at the top.

I don't think that I personally would worry about the detritus. I'd just let it degrade into nitrate and phosphate in the darkness and then use those nutrients to run my fuge through the night. I see why some people would care though.

 

[fish farmer]

True. It'd definitely be several hundred dollars for the water tank and materials to pull it off in my relatively small system. I can't shake the feeling that it would be worth it though, especially compared to the amount of money that I've invested in stuff like lights and controllers. But it's obviously not necessary.

An "Erasmus Tank".
That's incredibly amusing and I love it.




For one, I don't have space in my stand for a larger sump. But also, a sump is often open at the top and exposed to air. This allows for extra evaporation (with all the minor inconveniences that come with it) and it requires extra heating because it's not usually insulated. A sealed and insulated reservoir allows me to increase my water volume and stability with (theoretically) no extra maintanance work or ongoing costs.

Minimizing evaporation from a sump sounds like a good idea. I loose about 3 liters of water a week on my 29dt/20 sump.

 

[ScottB]

You could possibly remedy the temp mixing problem by using a pipe inside the reservoir to insert the water at the bottom and then remove the water with an overflow at the top.

I don't think that I personally would worry about the detritus. I'd just let it degrade into nitrate and phosphate in the darkness and then use those nutrients to run my fuge through the night. I see why some people would care though.

As long running the pipe to the bottom doesn't create any back pressure to the overflow pipe I suppose that might solve the mixing issue.

I am roughly familiar with the cryptic refugium concept, but in the long run, in a closed system, I don't know. A pile of gunk that doesn't get much aeration. Just doesn't jive for me. Once a year or so, I remove 150 lbs of rock from my 9' sump, rinse it, and vacuum out the inch of funky gunk.

 

[Reefer4fun]

I did implement the "Erasmus Tank" to increase water volume of a Waterbox 25 AIO. The new expansion tank is a sealed 17Gal capacity. It greatly stabilized alkalinity variations. So, it works

 

[Erasmus Crowley]

I did implement the "Erasmus Tank" to increase water volume of a Waterbox 25 AIO. The new expansion tank is a sealed 17Gal capacity. It greatly stabilized alkalinity variations. So, it works

Did you take pictures of the build process? I'd really enjoy seeing them if you did.

 

[RedoubtReef]

why not just use a larger sump that holds more water and/or add a refugium?

 

[Erasmus Crowley]

why not just use a larger sump that holds more water and/or add a refugium?

Really, this is a extra sump. Just a sealed one.

The sealed plumbing means that it requires doesn't create extra evaporation, so it doesn't effect your ATO. Being plumbed inline between the main tank and the sump means that you don't need to add any extra pumps. Being dark means you don't need extra lights. If it is insulated as I suggested, then you don't need to add extra heater capacity to the tank. If it's insulated well, it shouldn't require any extra electricity at all.

So you get all the benefits of larger water volume, with none of the downsides of a extra sump or refugium like evaporation, equipment, maintenance work, or energy cost. You just build it once and forget about it for a few years.