Large tank project Advice
- Thread starter Herpervet
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Herpervet
New member
H20ENG said:
What if the skimmer is inline so it would be above the level of the cistern. i.e.
Cistern -------> skimmer---------->back to cistern.
It would continually run on its own loop. An air vent can easily be added to the top of the cistern man hole which is the highest point.
Small diameter PVC plumbed and run up a wall so it is above the level of the sump and skimmer
Now if the skimmer is above the level of the sump where the main cistern loop is connected then there shouldn't be any risk of overflow through the skimmer right?
I feel like I am missing a major issue with this train of thought.....
Thats what I just drew up! Ok scratched out. Let me draw it up
Also, the return to the cistern from the tank system would just be a standpipe in the sump, so that whenever the 3way fed chilled water, that same amount would go back to the cistern
This ROCKS!
Also, the return to the cistern from the tank system would just be a standpipe in the sump, so that whenever the 3way fed chilled water, that same amount would go back to the cistern
This ROCKS!
Herpervet
New member
"As far as the topoff- a safe move is to have a valve dialed down on your topoff so that it can only fill so much in a certain period. This is mechanical, plus a timer is a good idea."
I'm not clear on this part. Do you mean just a flow restriction so it is a trickle rather than a gusher?
I'm not clear on this part. Do you mean just a flow restriction so it is a trickle rather than a gusher?
Ok, so the circ pump continuously skims and overflows back to the cistern- overflow provides vent, but the whole water level is still above the height of lid.
When calling for cooling, the 3way opens letting the chilled water flow now go to the tank. This water mixes with the tank water to get a good reading. A serpentine path in the sump will help this.
A standpipe in the sump- opposite side of the main pump suction- will return the amount of water pumped out of the cistern- to the cistern.
The circ pump needs to have a flooded suction, so I suggest still sealing the lid, the plumbing will allow it to vent.
I would put a ball valve inline with the 3 way so you can dial the flow back if its too much shock to the system. the 3way is either open or closed, not adjustable.
This should work!!!
Sorry for the quick and dirty pic
When calling for cooling, the 3way opens letting the chilled water flow now go to the tank. This water mixes with the tank water to get a good reading. A serpentine path in the sump will help this.
A standpipe in the sump- opposite side of the main pump suction- will return the amount of water pumped out of the cistern- to the cistern.
The circ pump needs to have a flooded suction, so I suggest still sealing the lid, the plumbing will allow it to vent.
I would put a ball valve inline with the 3 way so you can dial the flow back if its too much shock to the system. the 3way is either open or closed, not adjustable.
This should work!!!
Sorry for the quick and dirty pic
Herpervet
New member
WOW! I am a complete idiot when it comes to diagrams on a pc. Nice "dirty" diagram. I can't wait to see the REALLY nice one.
Now I need to ruminate on this to make certain I really understand all the details.
Ironic that I started the "Large Reef Aquarium on a budget" thread huh?
:lol:
Now I need to ruminate on this to make certain I really understand all the details.
Ironic that I started the "Large Reef Aquarium on a budget" thread huh?
:lol:
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Herpervet
New member
Ok. Your design would require three bulkheads in the cistern and I guess you left out the vent hole which would make four right?
What if the Skimmer leg blue line was plumbed to the red line from the stand pipe but just below the level of the sump.
Would this allow me to use only two bulkheads in the cistern plus the vent (so three total)?
The water would flow down hill rather than back up the stand pipe right? I would think that even if the skimmer was above the sump it would just go down hill.
Actually that stand pipe accoplishes the venting also doesn't it? As long as the connection to the cistern is above the water level it should work. No?
What if the Skimmer leg blue line was plumbed to the red line from the stand pipe but just below the level of the sump.
Would this allow me to use only two bulkheads in the cistern plus the vent (so three total)?
The water would flow down hill rather than back up the stand pipe right? I would think that even if the skimmer was above the sump it would just go down hill.
Actually that stand pipe accoplishes the venting also doesn't it? As long as the connection to the cistern is above the water level it should work. No?
Herpervet
New member
If the plumbing is done the way you have it show so far:
I must keep the sump water level below the stand pipe.
Once the water level rises and flows down the stand pipe and the cistern is vented the end result is that the cistern becomes the sump. (i.e. it will drop in level with evaporation)
I need to think on this more but I kinda think that the solution would be to have a way to shut down the vent and the skimmer leg when the system is feeding cool water into the system.'
i.e. the problem here is to switch from an open vented system when you have a skimmer running to a closed loop.
I must keep the sump water level below the stand pipe.
Once the water level rises and flows down the stand pipe and the cistern is vented the end result is that the cistern becomes the sump. (i.e. it will drop in level with evaporation)
I need to think on this more but I kinda think that the solution would be to have a way to shut down the vent and the skimmer leg when the system is feeding cool water into the system.'
i.e. the problem here is to switch from an open vented system when you have a skimmer running to a closed loop.
two thoughts
one is if you have a standpipe in the sump, determining how much water you need to replace due to evaporation would be difficult (but a guess would likely suffice). The best option would be to have the top off regulation in the cistern.
second is would you really need a "skimmer", why not simply have the 3 way valve feed into a reduced diameter pipe, the end of which is inserted into a pipe of larger diameter. This would provide all the aeration needed, unless you are trying to actually process the water to remove particulates? If you are trying to remove solid wastes, the skimmer should be placed in line with the returns from both the standpipe and the 3-way closed loop, once the solids get to the cistern, I don't think they will move much with the large volume, unless you have a very powerful recirculating pump. (edit) And actually, the skimmer would only need to be on the standpipe, the recirculating loop wouldn't really need to go through the skimmer if my guess is correct.
actually, a third thought for the price of 2:
A T with 2 adjustable valves would be better than the 3-way full open/close only and would allow you the option of having some control over the rate of cooling, though there are many factors at work here to determine what it should be set at, unless your goal is to completely automate the 3 way valve connected to something monitoring the temperature.
one is if you have a standpipe in the sump, determining how much water you need to replace due to evaporation would be difficult (but a guess would likely suffice). The best option would be to have the top off regulation in the cistern.
second is would you really need a "skimmer", why not simply have the 3 way valve feed into a reduced diameter pipe, the end of which is inserted into a pipe of larger diameter. This would provide all the aeration needed, unless you are trying to actually process the water to remove particulates? If you are trying to remove solid wastes, the skimmer should be placed in line with the returns from both the standpipe and the 3-way closed loop, once the solids get to the cistern, I don't think they will move much with the large volume, unless you have a very powerful recirculating pump. (edit) And actually, the skimmer would only need to be on the standpipe, the recirculating loop wouldn't really need to go through the skimmer if my guess is correct.
actually, a third thought for the price of 2:
A T with 2 adjustable valves would be better than the 3-way full open/close only and would allow you the option of having some control over the rate of cooling, though there are many factors at work here to determine what it should be set at, unless your goal is to completely automate the 3 way valve connected to something monitoring the temperature.
"Actually that stand pipe accoplishes the venting also doesn't it? As long as the connection to the cistern is above the water level it should work. No?"
You could have the standpipe drain line also be the vent and the skimmer return IF it was large enough. You dont want it burping. Go for a 3" er, use some DWV wyes and then plumb your standpipe, vent, and skimmer return to them.
Then you want at least a 1" bulkhead (preferrably 1.5") for the circ pump suction. I would have it draw from the bottom of the cistern so you get good mixing. 2 bulkheads
Yes, the standpipe needs to be just above normal sump water level, and skimmer needs to be above the level of the cistern.
You also could have the skimmer return / standpipe flow to a box with floss or filter sock before returning to the cistern. You really dont want crud in that tank.
"Once the water level rises and flows down the stand pipe and the cistern is vented the end result is that the cistern becomes the sump. (i.e. it will drop in level with evaporation)"
Yes, if the tank never calls for cooling, the cistern water will evaporate a bit. You could run a bypass to always trickle a bit of chilled water into the tank, thus always overflowing the standpipe. Then your regular makeup water would serve both.
"I need to think on this more but I kinda think that the solution would be to have a way to shut down the vent and the skimmer leg when the system is feeding cool water into the system."
The 3way shuts down the skimmer (recirc mode) when feeding the tank. You dont really want to shut off the vent.
nonot8946,
"one is if you have a standpipe in the sump, determining how much water you need to replace due to evaporation would be difficult (but a guess would likely suffice). The best option would be to have the top off regulation in the cistern."
See above.
"second is would you really need a "skimmer", why not simply have the 3 way valve feed into a reduced diameter pipe, the end of which is inserted into a pipe of larger diameter. This would provide all the aeration needed, unless you are trying to actually process the water to remove particulates? If you are trying to remove solid wastes, the skimmer should be placed in line with the returns from both the standpipe and the 3-way closed loop, once the solids get to the cistern, I don't think they will move much with the large volume, unless you have a very powerful recirculating pump. (edit) And actually, the skimmer would only need to be on the standpipe, the recirculating loop wouldn't really need to go through the skimmer if my guess is correct."
Correct, but I was thinking that the skimmer would get some of the gunk, which will happen wherever you aerate water. I would put some floss to catch any crud before entering the cistern. Just make sure it can still overflow safely if it gets clogged. You'd rather have a bit of crud in the cistern than a flood.
"A T with 2 adjustable valves would be better than the 3-way full open/close only and would allow you the option of having some control over the rate of cooling, though there are many factors at work here to determine what it should be set at, unless your goal is to completely automate the 3 way valve connected to something monitoring the temperature."
You want this thermostatically controlled. Too many factors effecting temps to do it manually. The rate of cooling is adjusted by an inline ballvalve with the 3way.
Herp,
So is it done yet?
You could have the standpipe drain line also be the vent and the skimmer return IF it was large enough. You dont want it burping. Go for a 3" er, use some DWV wyes and then plumb your standpipe, vent, and skimmer return to them.
Then you want at least a 1" bulkhead (preferrably 1.5") for the circ pump suction. I would have it draw from the bottom of the cistern so you get good mixing. 2 bulkheads
Yes, the standpipe needs to be just above normal sump water level, and skimmer needs to be above the level of the cistern.
You also could have the skimmer return / standpipe flow to a box with floss or filter sock before returning to the cistern. You really dont want crud in that tank.
"Once the water level rises and flows down the stand pipe and the cistern is vented the end result is that the cistern becomes the sump. (i.e. it will drop in level with evaporation)"
Yes, if the tank never calls for cooling, the cistern water will evaporate a bit. You could run a bypass to always trickle a bit of chilled water into the tank, thus always overflowing the standpipe. Then your regular makeup water would serve both.
"I need to think on this more but I kinda think that the solution would be to have a way to shut down the vent and the skimmer leg when the system is feeding cool water into the system."
The 3way shuts down the skimmer (recirc mode) when feeding the tank. You dont really want to shut off the vent.
nonot8946,
"one is if you have a standpipe in the sump, determining how much water you need to replace due to evaporation would be difficult (but a guess would likely suffice). The best option would be to have the top off regulation in the cistern."
See above.
"second is would you really need a "skimmer", why not simply have the 3 way valve feed into a reduced diameter pipe, the end of which is inserted into a pipe of larger diameter. This would provide all the aeration needed, unless you are trying to actually process the water to remove particulates? If you are trying to remove solid wastes, the skimmer should be placed in line with the returns from both the standpipe and the 3-way closed loop, once the solids get to the cistern, I don't think they will move much with the large volume, unless you have a very powerful recirculating pump. (edit) And actually, the skimmer would only need to be on the standpipe, the recirculating loop wouldn't really need to go through the skimmer if my guess is correct."
Correct, but I was thinking that the skimmer would get some of the gunk, which will happen wherever you aerate water. I would put some floss to catch any crud before entering the cistern. Just make sure it can still overflow safely if it gets clogged. You'd rather have a bit of crud in the cistern than a flood.
"A T with 2 adjustable valves would be better than the 3-way full open/close only and would allow you the option of having some control over the rate of cooling, though there are many factors at work here to determine what it should be set at, unless your goal is to completely automate the 3 way valve connected to something monitoring the temperature."
You want this thermostatically controlled. Too many factors effecting temps to do it manually. The rate of cooling is adjusted by an inline ballvalve with the 3way.
Herp,
So is it done yet?
Herpervet
New member
I can't tell you how much I appreciate your helping out with this. I need to study your thoughts a bit more to make sure I really understand all of it.
Not quite done yet but gettin' there. The manhole extension will go on tomorrow. Four 1.5 inch bulk head fittings and 1.5 inch pvc plumbed next to the stand. I'm sure they won't be in the most convenient location but we can't hold up the project any longer to decide on better placement.
Two of the bulkheads will have pvc extensions to near the bottom of the cistern. Should we go ahead and put flapper type check valves one or both of these? This would allow easier priming for the pump. I don't think I want a check valve on both of these but I'm not sure. (i.e. I don't anticipate using more than one pump to draw water out of the cistern)
Not quite done yet but gettin' there. The manhole extension will go on tomorrow. Four 1.5 inch bulk head fittings and 1.5 inch pvc plumbed next to the stand. I'm sure they won't be in the most convenient location but we can't hold up the project any longer to decide on better placement.
Two of the bulkheads will have pvc extensions to near the bottom of the cistern. Should we go ahead and put flapper type check valves one or both of these? This would allow easier priming for the pump. I don't think I want a check valve on both of these but I'm not sure. (i.e. I don't anticipate using more than one pump to draw water out of the cistern)
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As long as the circ pump will have a flooded suction (It needs to- you wont have much flow if it has to suck the water up), you shouldnt need check valves. I'm picturing the manhole sticking up about a foot, and the pump residing on the floor next to it, so that the cistern water level is above the pump.
Also, The high point in the cistern - the manhole extension- is where the air will collect and will need to be vented from there.
A U loop of PVC MIGHT work to plumb the vent over to the side, or put a bulkhead in the side of the extension toward the top.
Glad to help, and cant wait to see the finished product!
Also, The high point in the cistern - the manhole extension- is where the air will collect and will need to be vented from there.
A U loop of PVC MIGHT work to plumb the vent over to the side, or put a bulkhead in the side of the extension toward the top.
Glad to help, and cant wait to see the finished product!
Herpervet
New member
Actually the man hole is below ground level by about 15 inches. I am so cramped for room there was really no way around it.
So we are talking about significant up-hill and non-flooded suction. I can put a leaf basket to prime the pump if needed but the guy at sequence said that a foot valve/check valve would do the job.
I am trying to modify your drawing so I can ask a more intelligable question. I will do it later on tonight.
thanks
Pete
So we are talking about significant up-hill and non-flooded suction. I can put a leaf basket to prime the pump if needed but the guy at sequence said that a foot valve/check valve would do the job.
I am trying to modify your drawing so I can ask a more intelligable question. I will do it later on tonight.
thanks
Pete
If the manhole is sealed, but the water in the vent line is above the level of the pump suction, then the pump will have a flooded suction, as long as the level in the standpipe is above the pump suction.
To put it another way, shut everything off. The static water level is the total water level in that system. Put the pump below taht level and you will have no problems.
To put it another way, shut everything off. The static water level is the total water level in that system. Put the pump below taht level and you will have no problems.
Herpervet
New member
Do you mean fill the cistern to the top and have the vent partially filled also?
I really want to avoid this because the manhole extension is bolted on (stainless) and sealed with silicone but over time I'm worried it would eventually leak.
The guy from sequence didn't seem to think it would be a huge problem but that is contrary to what I have heard elsewhere.
Will pulling the water up 15 to 20 inches result in damage to the pump or is it mainly decreased efficiency?
If its the latter then I'm not too worried because flow rate out of the cistern isn't critical and slower rates might actually be better.
"Do you mean fill the cistern to the top and have the vent partially filled also? "
Yep.
If you dont want to run past the lid, you will have to use a submersible or have a negative NPSH (Net positive suction head).
So you will need the leaf basket and the foot valve.
You shouldnt need a large sequence for this, maybe a genX 70 or so.
It wont hurt the pump, just efficiency. At my last job, I installed 4 BIG sequence pumps in parallel at about a 14" negative NPSH, and they run fine. They pump up 2 floors to multiple large exhibit tanks. Ok, maybe you do want the sequence.
Also take a look at www.performancepropumps.com. I like these pumps better than sequence (on paper and what I've heard of them). Much better numbers in both pressure, flow AND watts!
Yep.
If you dont want to run past the lid, you will have to use a submersible or have a negative NPSH (Net positive suction head).
So you will need the leaf basket and the foot valve.
You shouldnt need a large sequence for this, maybe a genX 70 or so.
It wont hurt the pump, just efficiency. At my last job, I installed 4 BIG sequence pumps in parallel at about a 14" negative NPSH, and they run fine. They pump up 2 floors to multiple large exhibit tanks. Ok, maybe you do want the sequence.
Also take a look at www.performancepropumps.com. I like these pumps better than sequence (on paper and what I've heard of them). Much better numbers in both pressure, flow AND watts!
Herpervet
New member
Here is what I have so far.
I put in the second float in the cistern because when the flow is as depicted in the bottom diagram, the cistern is where the level drops with evaporation.
In the first diagram, the water level in the sump will drop the most since its the only circuit running with the diplay (where the heat is added) but the cistern level can still drop from evaporation because the skimmer will cause some evaporation (although this should be minimal).
I kinda think the first mode, where the cistern water is being added to the system, will be the one that runs the most but with AC and excellent ventialtion to the wet-room I could be wrong.
I put in the second float in the cistern because when the flow is as depicted in the bottom diagram, the cistern is where the level drops with evaporation.
In the first diagram, the water level in the sump will drop the most since its the only circuit running with the diplay (where the heat is added) but the cistern level can still drop from evaporation because the skimmer will cause some evaporation (although this should be minimal).
I kinda think the first mode, where the cistern water is being added to the system, will be the one that runs the most but with AC and excellent ventialtion to the wet-room I could be wrong.
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if you have the recirc pump above the cistern, you are going to need an easy way of priming it.
You might want to plumb something like a shutoff on the sump overflow and T with shutoff valves in somewhere for a cleanout, so that you could pump most of the water out of your cistern into temporary containers every once in awhile as you may have to clean out the crud every few years or in case you needed to tinker with it, or in case you ever needed to do a large waterchange, you can just open it up and point the hose at the sink..
You might want to plumb something like a shutoff on the sump overflow and T with shutoff valves in somewhere for a cleanout, so that you could pump most of the water out of your cistern into temporary containers every once in awhile as you may have to clean out the crud every few years or in case you needed to tinker with it, or in case you ever needed to do a large waterchange, you can just open it up and point the hose at the sink..
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