Volcano club
- Thread starter tom obrecht
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hahnmeister
In Memoriam
Yeniraki, your skimmers do not look much like Volcanoes w/ respect to dimensions/pumps. FWIW, Nanook's isnt much the same as well besides the diamter of the neck and body. Nanook, your neck is quite a bit taller, which seems like it helps your situation as well, not to mention, you most likely are running a much better impeller than the 'Volcano' Dart impeller, so you can run 3900lph of air or more and not worry about the mixing pump 'burping' up larger bubbles. One of the biggest problems with the Volcano needlewheel is that it cant handle/generate as much water flow on its own (needs more needles, mesh, etc), so it cant draw as much air, nor handle as much if force fed. Thats where most any solution for the Volcano starts, otherwise it seems that even 3900lph (alita 40) can be too much for the pump to blend enough (passes some large bubbles).
I do have a correction to make though too:
"Yeniraki noted that by turning down the gate valve you increase air aspiration via the venturi effect."
Im not sure where Yeniraki said this... I didnt see it (but this thread is getting a little nuts so I most likely missed it or it was phrased different)... but that statement is actually wrong.
FWIW, it could be seen as a major flaw in the design for some of the earlier 'venturis' that I have seen... varying the valve has nothing to do with the venturi, simply varying the restriction of water flow going into the pump. The ONLY way to adjust a venturi is through varying the venturi's diameter (its point of narrowest restriction). A venturi works not as a valve (otherwise, we would all just have a T'ed inlet for our needlewheels with one valve for air, and one for water... assuming that less of one would mean more of another or something like that)... it works by increasing the velocity of the water (by narrowing the pipe diameter but trying to keep the volume of flow as much as possible)... when water increases in velocity, its pressure (at a perpendicular) drops... sucking in air. So unless a 'valve then venturi' assembly can actually increase the water velocity by restricting/opening the valve before the venturi (which it doesnt)... you arent doing anything. Think about it... if you restrict the water at the valve... all you are doing is lowering the water flow rate going through the skimmer, so if anything, you are dropping the water velocity, and actually hurting the venturi.
So in short, while having/adjusting the valve in front of your venturi might SEEM like its changing something in a good way, all it can do in reality is harm it and performance wise it does nothing. The best idea is to leave the valve 100% open.
Now if you are force feeding... its a different story... then you can adjust the relative throughputs of water and air with valves in the air and water inlets. A venturi does very little then. It might help blend the air into the water before the needlewheel a little better so the needlewheel has more 'bite', but a good needlewheel will make short order of large bubbles anyways.
The best solutions are still to:
1. just add a linear air pump: the 'problem skimmer' here seems to be the 18" diameter, 4' tall ones that aren't force fed. That body diameter and 6-8" neck should easily handle 4000lph at the neck, and up to 2x that in the body... but going over 4000lph means you are going to have to drop the waterline below the reducer, and this can lead to other problems (or, it can be just fine).
2. modify the pump: add mesh, more pins, or a whole new impeller all together to the dart motor. Now it will draw more air on its own from more 'bite' into the water (yet its not likely to be enough), and be able to handle more air if force fed.
3. add airstones: Leave the pump alone sucking its 1200-1400lph of air, and add an array of fine ceramic airstones being fed by a linear air pump.
4. change the pump... a hammerhead needlewheel would work on its own... drawing over 4000lph (most likely 7000lph or more) without needing an air pump. Thats a high wattage motor though.
The one remaining problem is the reducer... an 18" body can handle much more than 4000lph, but an 8" neck cant... well... not unless you have a reducer that is very steep (which allows bubbles to rise above the 'waterline' without getting trapped under it). I can see that Nanook's skimmer uses this (along with a taller neck in proportion which does help). This way... you can get away with adding alot more air than a given neck diameter can normally handle... because the 'waterline' is down in the reducer somewhere, but the 'resistance' of the steeper 'funnel' doesnt disrupt the foam as it rises... only gently condensing it. Something that might work (besides a cone body swap out or a larger neck being added) is to make the neck taller... by 6" about. This isn't ideal, but it would be a way to compensate because it would move the waterline up higher in the skimmer.
I do have a correction to make though too:
"Yeniraki noted that by turning down the gate valve you increase air aspiration via the venturi effect."
Im not sure where Yeniraki said this... I didnt see it (but this thread is getting a little nuts so I most likely missed it or it was phrased different)... but that statement is actually wrong.
FWIW, it could be seen as a major flaw in the design for some of the earlier 'venturis' that I have seen... varying the valve has nothing to do with the venturi, simply varying the restriction of water flow going into the pump. The ONLY way to adjust a venturi is through varying the venturi's diameter (its point of narrowest restriction). A venturi works not as a valve (otherwise, we would all just have a T'ed inlet for our needlewheels with one valve for air, and one for water... assuming that less of one would mean more of another or something like that)... it works by increasing the velocity of the water (by narrowing the pipe diameter but trying to keep the volume of flow as much as possible)... when water increases in velocity, its pressure (at a perpendicular) drops... sucking in air. So unless a 'valve then venturi' assembly can actually increase the water velocity by restricting/opening the valve before the venturi (which it doesnt)... you arent doing anything. Think about it... if you restrict the water at the valve... all you are doing is lowering the water flow rate going through the skimmer, so if anything, you are dropping the water velocity, and actually hurting the venturi.
So in short, while having/adjusting the valve in front of your venturi might SEEM like its changing something in a good way, all it can do in reality is harm it and performance wise it does nothing. The best idea is to leave the valve 100% open.
Now if you are force feeding... its a different story... then you can adjust the relative throughputs of water and air with valves in the air and water inlets. A venturi does very little then. It might help blend the air into the water before the needlewheel a little better so the needlewheel has more 'bite', but a good needlewheel will make short order of large bubbles anyways.
The best solutions are still to:
1. just add a linear air pump: the 'problem skimmer' here seems to be the 18" diameter, 4' tall ones that aren't force fed. That body diameter and 6-8" neck should easily handle 4000lph at the neck, and up to 2x that in the body... but going over 4000lph means you are going to have to drop the waterline below the reducer, and this can lead to other problems (or, it can be just fine).
2. modify the pump: add mesh, more pins, or a whole new impeller all together to the dart motor. Now it will draw more air on its own from more 'bite' into the water (yet its not likely to be enough), and be able to handle more air if force fed.
3. add airstones: Leave the pump alone sucking its 1200-1400lph of air, and add an array of fine ceramic airstones being fed by a linear air pump.
4. change the pump... a hammerhead needlewheel would work on its own... drawing over 4000lph (most likely 7000lph or more) without needing an air pump. Thats a high wattage motor though.
The one remaining problem is the reducer... an 18" body can handle much more than 4000lph, but an 8" neck cant... well... not unless you have a reducer that is very steep (which allows bubbles to rise above the 'waterline' without getting trapped under it). I can see that Nanook's skimmer uses this (along with a taller neck in proportion which does help). This way... you can get away with adding alot more air than a given neck diameter can normally handle... because the 'waterline' is down in the reducer somewhere, but the 'resistance' of the steeper 'funnel' doesnt disrupt the foam as it rises... only gently condensing it. Something that might work (besides a cone body swap out or a larger neck being added) is to make the neck taller... by 6" about. This isn't ideal, but it would be a way to compensate because it would move the waterline up higher in the skimmer.
jnarowe
New member
Nice write up Hahn...
Looks to me like Nanook is reducing the hose size out of his Alita quite a bit. I wonder if going with a larger hose would help on his and the Volcanos? I know on mine, by moving to a 5/8" hose, I greatly improved the performance of my skimmer as well as reduced the back pressure on the air pump. This in turn lowered the wattage from 120 to 105.
Looks to me like Nanook is reducing the hose size out of his Alita quite a bit. I wonder if going with a larger hose would help on his and the Volcanos? I know on mine, by moving to a 5/8" hose, I greatly improved the performance of my skimmer as well as reduced the back pressure on the air pump. This in turn lowered the wattage from 120 to 105.
hahnmeister
In Memoriam
Its just a restriction on the air pump since they went to smaller diameter hoses, not larger... so maybe rather than getting 3900lph from the AL-40, its only getting 3000, or only 6000lph from the AL-80.
hahnmeister
In Memoriam
Well, thats a different story... larger diameter pipe (up to a certain point) will unrestrict the air pump some, yes...
Herpervet
New member
I do have a correction to make though too:
"Yeniraki noted that by turning down the gate valve you increase air aspiration via the venturi effect."
Im not sure where Yeniraki said this... I didnt see it (but this thread is getting a little nuts so I most likely missed it or it was phrased different)... but that statement is actually wrong.
Hahn,
Here is what I can report. I don't know if it changes anything in the end and I am only reporting this as an fyi so let me clarify:
I don't have a true venturi valve in that there is no narrowing of the diamter of the inlet tube to the dart. There is simply a 1/2" pvc tube that enter immediately after the gate valve and before the inlet of the dart.
Here is what I observed:
I turned off my alita and left the dart running. Water backed up into the clear air hose by about 18"
I then started closing the gate valve and as I did this it started to aspirate air and alot of it.
Basically the gate valve is functioning as the venturi in that as you close the valve you get a smaller orifice for the water to flow through which results in higher speed of the water.
This creates negative pressure and air is aspirated as a result.
This is what I interpreted Yeneraki to be describing. Anyway, as I blocked water flow there is a point where air is aspirated.
It is not exactly the same configuration as a classic venturi valve since the air inlet tube isn't placed in the narrow spot of the tube but somewhat after that spot.
Nevertheless, air is aspirated as the gate valve is stopped down.
"Yeniraki noted that by turning down the gate valve you increase air aspiration via the venturi effect."
Im not sure where Yeniraki said this... I didnt see it (but this thread is getting a little nuts so I most likely missed it or it was phrased different)... but that statement is actually wrong.
Hahn,
Here is what I can report. I don't know if it changes anything in the end and I am only reporting this as an fyi so let me clarify:
I don't have a true venturi valve in that there is no narrowing of the diamter of the inlet tube to the dart. There is simply a 1/2" pvc tube that enter immediately after the gate valve and before the inlet of the dart.
Here is what I observed:
I turned off my alita and left the dart running. Water backed up into the clear air hose by about 18"
I then started closing the gate valve and as I did this it started to aspirate air and alot of it.
Basically the gate valve is functioning as the venturi in that as you close the valve you get a smaller orifice for the water to flow through which results in higher speed of the water.
This creates negative pressure and air is aspirated as a result.
This is what I interpreted Yeneraki to be describing. Anyway, as I blocked water flow there is a point where air is aspirated.
It is not exactly the same configuration as a classic venturi valve since the air inlet tube isn't placed in the narrow spot of the tube but somewhat after that spot.
Nevertheless, air is aspirated as the gate valve is stopped down.
lvpd186
Reefing in NE
If I remember right Klaus came on to this thread and recommended more pins as well (I think he even gave a measurement between pins). Would there be an adverse effect to creating a new NW with more pins? It would seem that the current ones (at least the ones that have posted photos) have pins that are spaced far apart with several holes in the base. Also would there be some benefit to making a NW with a variation of pin height; for example having a row of longer pins on the outside?
saleencobra
Premium Member
Mine has the modded nw via Scott. It has 108 pins instead of 48.I know the 1875 is a little different from the smaller skimmers but the nw has to help. Most of the mesh mod threads I have read say to cut off the pins to add mesh but I don't want to do that. Can I put mesh over the pins and get the same effect?
So for a new NW it seems that there are 2 options (aside from purchasing a commercial one, which I am not against either). Those two options are to :
1. Drill and add more pins to our existing NWs. That would seem to require that we balance the new pins across from each other to keep the NW itself balanced (or am I overlooking something simple ?)
2. Add mesh to our existing NWs, otherwise known as the "mesh mod" these days. I recall the Klaus recommended against this, especially for the high RPM pumps. Would the Dart be considered a high RPM pump ? or lower than say an OR pump ? (seems that the larger pumps like the Dart wouldn't necessarily need to spin as fast as the smaller pumps that are typical to a skimmer)
Of the two it seems that the mesh mod would be the easiest to NOT throw the NW out of balance and the easiest physically to implement (no real drilling, major glusing, etc involved. I had seen some links a while back to sources for the mesh that most people were using. What would anyone recommend for a mesh to use to mod these NWs. This is for the 1860 skiimer force fed by an Alita. Oh, and I do use ozone, so ozone resistant mesh would be needed.
As for acquiring a commercial NW, there are several out there now that fit onto the Dart shaft (and they shuold fit the volute (sp?) since Scott already enlarged it to fit his NW). But what I don't know is if any are available unattached to a Dart/skimmer.
Oh, and I am pretty sure that our hose from the Alita is 5/8" or even 3/4" ID, but it does get reduced down to 1/2" PVC when it hits the skimmer, maybe 8' or so between the hose and venturi.
1. Drill and add more pins to our existing NWs. That would seem to require that we balance the new pins across from each other to keep the NW itself balanced (or am I overlooking something simple ?)
2. Add mesh to our existing NWs, otherwise known as the "mesh mod" these days. I recall the Klaus recommended against this, especially for the high RPM pumps. Would the Dart be considered a high RPM pump ? or lower than say an OR pump ? (seems that the larger pumps like the Dart wouldn't necessarily need to spin as fast as the smaller pumps that are typical to a skimmer)
Of the two it seems that the mesh mod would be the easiest to NOT throw the NW out of balance and the easiest physically to implement (no real drilling, major glusing, etc involved. I had seen some links a while back to sources for the mesh that most people were using. What would anyone recommend for a mesh to use to mod these NWs. This is for the 1860 skiimer force fed by an Alita. Oh, and I do use ozone, so ozone resistant mesh would be needed.
As for acquiring a commercial NW, there are several out there now that fit onto the Dart shaft (and they shuold fit the volute (sp?) since Scott already enlarged it to fit his NW). But what I don't know is if any are available unattached to a Dart/skimmer.
Oh, and I am pretty sure that our hose from the Alita is 5/8" or even 3/4" ID, but it does get reduced down to 1/2" PVC when it hits the skimmer, maybe 8' or so between the hose and venturi.
hahnmeister
In Memoriam
It is operating like a 'dual valve' setup, like I mentioned before... the pump is given enough water so it can create a suction... then with the valve you are restricting the intake suction to make it even more... sucking in air. This is not a venturi, nor is it nearly as efficient because you arent actually using the water velocity to create a suction, you are using the pump itself... in a way, it is working against itself. Think about it, as you close the valve, you arent actually increasing the water velocity... the water has the same area to flow through where it comes in, you are just limiting the flow, if anything, this works against the venturi effect.
There are ways to have an adjustable throat venturi, but they are much more complicated than just having a valve in front of the venturi... much more efficient as well. The simplest way, of course, is to just have removable inserts for the venturi. The more complicated and 'adjustable on the fly' method is a combo of an center body and traditional venturi (much like a pistol grip garden hose attachment), or an adjustable aperture, like a camera... not easy. This is one of the problems with the Volcano venturis... they shouldnt need or use a valve to 'adjust' them.
hahnmeister
In Memoriam
Just a speculation here, but Klaus's work with mesh was with Matala, a rubbery material that actually comes apart rather easily (I have it also). I dont know that he ever used enkamat. FWIW, these motors are not 'high speed' at all... Darts are low speed, flow biased, etc... enkamat should hold up just fine.
As for attaching it... you could order a stock impeller from Sequence... shave off the blades and drill it with holes to attach mesh. But you should also be able to just attach enkamat to the needlewheel by putting it right over the needles that are on there. That should improve things a bit... then we can work on the venturi. That requires someone with an actual kill-a-watt though... Im thinking a 1" venturi diameter is about right, not this 1.30-1.4" stuff.
I have a volcano type skimmer too. 27in diameter by 67in tall run by a dart NW and force fed by an extremely bled off alita 100 and like so many other people on this thread, I am completely dissatisfied by the result.
It is on a 1000gal reef and 750gal FOWLR system. Total volume is 2200g. At first I thought I just didn't have enough disssolved organics for the skimmer to pull out since the system is only 5months old. It was barely developing enough foam to produce 1/2 gal of skimmate daily.
I finally hooked up my $150 DIY 14in dia by 64in PVC skimmer (pvc body and acrylic cone and neck) next to it after 1 month of messing with the volcano type skimmer. This skimmer was copied from jnarowe.. a simple airstone driven skimmer connected to an alita 100 with zero bleed off. Within 1 day the cheap skimmer had produced close to 5 gal of skimmate. Obviously not coffee colored but I set it a little drier and got 2 gal of dark smelly skimate 1.5 days later. I have been starring at both of them side by side now for about 1hr and I think I am gonna make like Jnarowe and google and go the way of simple!! The cheap DIY is so easy to tune. No Killawatt meters, no air meters, no wondering if I have enough needles on the NW, no messing with 100 gate valves, no meshmods, no cone bodies, no wondering about neck size.......... just water input (wide open-I don't even have a valve on that) and air input(no valve there either). Only valve I have on the air stone skimmer is water output/level from the skimmer. One Knob!! what a beautiful thing.
I have spent countless hours going thru threads, reading and trying to gain as much knowledge as I can about this product. I paid over $4000 because I thought this new technology would be so awesome and I definitely wanted to own the latest and greatest skimmer out there (not too sure if this was more for the safety of my pets or just for my ego) only to find out the original skimmer is arguably still the best one. My only worry about the air stoen skimmer was maintenance on the stones. I finally cleaned out the stones 2 weeks ago while I was connecting the skimmer to the new system anyway. They had been going for close to 8 months and it was a simple matter of soaking in a weak muratic acid solution for a couple of hours and then rinsing with a hose. probably would have taken me twice as long to get an impeller off a pump.
Oh I almost forgot... the alita pump costs about the same as a dart NW and uses less watts so its also cheaper.
Ok I think I'm done. Sorry for the long rant. I think I just realized what to do when I started typing and it's been a frustrating 3months
It is on a 1000gal reef and 750gal FOWLR system. Total volume is 2200g. At first I thought I just didn't have enough disssolved organics for the skimmer to pull out since the system is only 5months old. It was barely developing enough foam to produce 1/2 gal of skimmate daily.
I finally hooked up my $150 DIY 14in dia by 64in PVC skimmer (pvc body and acrylic cone and neck) next to it after 1 month of messing with the volcano type skimmer. This skimmer was copied from jnarowe.. a simple airstone driven skimmer connected to an alita 100 with zero bleed off. Within 1 day the cheap skimmer had produced close to 5 gal of skimmate. Obviously not coffee colored but I set it a little drier and got 2 gal of dark smelly skimate 1.5 days later. I have been starring at both of them side by side now for about 1hr and I think I am gonna make like Jnarowe and google and go the way of simple!! The cheap DIY is so easy to tune. No Killawatt meters, no air meters, no wondering if I have enough needles on the NW, no messing with 100 gate valves, no meshmods, no cone bodies, no wondering about neck size.......... just water input (wide open-I don't even have a valve on that) and air input(no valve there either). Only valve I have on the air stone skimmer is water output/level from the skimmer. One Knob!! what a beautiful thing.
I have spent countless hours going thru threads, reading and trying to gain as much knowledge as I can about this product. I paid over $4000 because I thought this new technology would be so awesome and I definitely wanted to own the latest and greatest skimmer out there (not too sure if this was more for the safety of my pets or just for my ego) only to find out the original skimmer is arguably still the best one. My only worry about the air stoen skimmer was maintenance on the stones. I finally cleaned out the stones 2 weeks ago while I was connecting the skimmer to the new system anyway. They had been going for close to 8 months and it was a simple matter of soaking in a weak muratic acid solution for a couple of hours and then rinsing with a hose. probably would have taken me twice as long to get an impeller off a pump.
Oh I almost forgot... the alita pump costs about the same as a dart NW and uses less watts so its also cheaper.
Ok I think I'm done. Sorry for the long rant. I think I just realized what to do when I started typing and it's been a frustrating 3months
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You can put mesh over the pins but it will not perform as a complete mesh on the wheel.... the best result it's all mesh.
if you can modify a wheel impeller like what you have and to fit it on the pump it will be better also at this way you don't touch the original one... try to do something like this one (without the pins will be better & less Watt use)
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so is enkamat ozone resistant ? (I am sure that is answered in one of the mesh mod threads, but for the sake of my sanity I hoped someone here could answer that one). Also, I am guessing that the dart impellors are ordered through Sequence directly ? Or are there online vendors that actually stock and sell the parts/impellors ?
I think that we are going to tackle getting a stock impellor and modding it w/ mesh, as Hahn and a few others have recommended. That way I will still have the NW from Scott as a fall back option. Now I just need to source the parts and get them ordered
I think that we are going to tackle getting a stock impellor and modding it w/ mesh, as Hahn and a few others have recommended. That way I will still have the NW from Scott as a fall back option. Now I just need to source the parts and get them ordered
"Via the pump's water input valve, slightly decrease the water intake, while venturi valve is full open and see what happens, there will be a tremendous increase in the air intake"
I am repeating my statement again to clear up the confusion regarding valves. As I mentioned above the valve I meant was the Pump's water input valve, not the venturi valve.
I am repeating my statement again to clear up the confusion regarding valves. As I mentioned above the valve I meant was the Pump's water input valve, not the venturi valve.
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