Skimmer Pump Instead of Airstones?

HarryCooter

HarryCooter

Well-Known Member
I've been peicing together a new homemade rdwc system for the 4x8 tent I have, and I stumbled upon some old posts suggesting the use of a skimmer pump(venturi valve on the inlet of a needle wheel pump) instead of an air pump and stones. Although there was no mention of it being put into use. For those of you unfamiliar with these pumps, the bubble output looks similar to those o2 emitters(electrolysis device) just a lot more of them.

I'm thinking of using one of these pumps(1200 gph) to distribute from the resorvoir to the 8 buckets. I have been searching all over and I can't find an example of anyone actually trying this. Would this not be more beneficial than using air stones? Or atleast work in theory? If this is as awesome as it sounds, wouldnt there would be more people doing this?
 
Airwalker16

Airwalker16

Well-Known Member
I got 8 buckets currently using air stones. Interested in seeing if you dot his. I’d like to know how much, if any, more effective it is. My main goal is to switch from the commercial style heatsink lookin ass air pumps I use now to a LINEAR air pump like an Air Force. They’re the shit. So quiet.
 
Observe & Report

Observe & Report

Well-Known Member
Protein skimmers work well in sea water because the high surface tension (or something else) allows the formation of lots of tiny bubbles. In fresh water they don't work well at all, the bubbles are not fine. You can see the difference even with a regular airstone in a salt water tank: the bubbles are very fine.

It can certainly work to saturate your res with O2, you don't need super fine bubbles for that. Maybe it will free you from having to constantly clean/replace stones. Downsides include additional heat input from the pump.
 
HarryCooter

HarryCooter

Well-Known Member
Observe & Report said:
Protein skimmers work well in sea water because the high surface tension (or something else) allows the formation of lots of tiny bubbles. In fresh water they don't work well at all, the bubbles are not fine. You can see the difference even with a regular airstone in a salt water tank: the bubbles are very fine.

It can certainly work to saturate your res with O2, you don't need super fine bubbles for that. Maybe it will free you from having to constantly clean/replace stones. Downsides include additional heat input from the pump.
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I'm somewhat familiar with the basics of salt water tanks so I do understand that the salt plays a big role in the bubble size. Technically, I would be running salt water(nutrient salts), though it would be nothing compared to a tank. Hahaha. I was hoping someone would come forward with first hand experience trying this, but so far it appears I may have to be the test subject.
 
Lordhooha

Lordhooha

Well-Known Member
HarryCooter said:
I'm somewhat familiar with the basics of salt water tanks so I do understand that the salt plays a big role in the bubble size. Technically, I would be running salt water(nutrient salts), though it would be nothing compared to a tank. Hahaha. I was hoping someone would come forward with first hand experience trying this, but so far it appears I may have to be the test subject.
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Waterfall it or air pump combo ventri setups work ok just not the best in my opinion.
 
Budley Doright

Budley Doright

Well-Known Member
Observe & Report said:
Protein skimmers work well in sea water because the high surface tension (or something else) allows the formation of lots of tiny bubbles. In fresh water they don't work well at all, the bubbles are not fine. You can see the difference even with a regular airstone in a salt water tank: the bubbles are very fine.

It can certainly work to saturate your res with O2, you don't need super fine bubbles for that. Maybe it will free you from having to constantly clean/replace stones. Downsides include additional heat input from the pump.
Click to expand...
Why would there be additional heat as it's not another pump, it's the recirc pump? I watch a few videos as I was curious and the needle wheel pumps produce a ton of bubbles but just so I understand, it's not the bubbles that produce the DO, it when the bubbles hit the surface right? I use a pump that actually is like a fountain in the root chamber that hits the lid, it's like a chaotic water spout lol.
 
Observe & Report

Observe & Report

Well-Known Member
Budley Doright said:
Why would there be additional heat as it's not another pump, it's the recirc pump? I watch a few videos as I was curious and the needle wheel pumps produce a ton of bubbles but just so I understand, it's not the bubbles that produce the DO, it when the bubbles hit the surface right? I use a pump that actually is like a fountain in the root chamber that hits the lid, it's like a chaotic water spout lol.
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When you say recirc pump do you mean the pump that circulating water among your buckets and res or just something in the res to keep it stirred and oxygenated? I don't think using a venturi and needle wheel on the pump that circulates among your buckets is a good idea. The output is filled with bubbles which will fill your tubing with air. Watt for watt, an external air pump pushing air into the water is going to heat it less than a second water pump in contact with the water.

The O2 is in the air and the rate diffusion of O2 into the water is proportional to the area of the air-water interface. Adding bubbles increases the amount of water exposed to air, that's it.
 
HarryCooter

HarryCooter

Well-Known Member
Observe & Report said:
When you say recirc pump do you mean the pump that circulating water among your buckets and res or just something in the res to keep it stirred and oxygenated? I don't think using a venturi and needle wheel on the pump that circulates among your buckets is a good idea. The output is filled with bubbles which will fill your tubing with air. Watt for watt, an external air pump pushing air into the water is going to heat it less than a second water pump in contact with the water.

The O2 is in the air and the rate diffusion of O2 into the water is proportional to the area of the air-water interface. Adding bubbles increases the amount of water exposed to air, that's it.
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The idea would be to use the 1200gph needle wheel for recirculation and aeration as it distributes to the buckets. Im trying to go with a one pump solution. I will have to use something like a powerhead for the resevoir to keep it moving. The pump would be inline located in the center of the tent for even distribution and short travel distance for the bubbles. The temperature would not be any different then any other common pump used for recirculation. The bubbles in the distribution lines would only increase contact time with the air, which I would assume could only increase the amount of disolved o2.
 
HarryCooter

HarryCooter

Well-Known Member
The more stuff I see on skimmers in fresh water make me think it's not going to produce the size bubbles I'm after. I am still fairly confident it would provide enough saturation, but I'm trying to go optimal, not just sufficient. I did take a second look at a video showing a simple venturi on the output of a pump, and at the end the guy makes an adjustment at (1:25 into the video)to the airline and it made the bubbles significantly smaller, although there much less of them. Here's the video:


So I'm thinking maybe do a typical circulation pump, but feed two inlets to each bucket with two venturi's on both set to make these small bubbles?
 
Budley Doright

Budley Doright

Well-Known Member
I'm pretty sure you would produce enough do by just using two inlet tubes shooting water onto the surface at 1200 gph. Are you planning on chilling the water? I strongly recommend that ;). I dropped the air pumps and stones a few years ago, they clogged, seemed to fuck with my ph, and got all slimed lol.
 
HarryCooter

HarryCooter

Well-Known Member
Budley Doright said:
I'm pretty sure you would produce enough do by just using two inlet tubes shooting water onto the surface at 1200 gph. Are you planning on chilling the water? I strongly recommend that ;). I dropped the air pumps and stones a few years ago, they clogged, seemed to fuck with my ph, and got all slimed lol.
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I'm sure it would easily produce enough with that flow rate. Im confident I wouldnt need a venutri at that rate either. Im just trying to go somewhat perfectionist, although I know it is completely unnecessary. This isn't my first rodeo with dwc, but as I've mentioned in other threads I'm in this for the science more than the product. In the spirit of science, the first step needs to be running one of these pumps in a tank with a salinity of 300-600ppm, and testing the disolved o2 divided by 8 vs an air pump with the equivalence of 1 watt per gallon of solution. The recommended salinity in a salt water tank is around 3600ppm which is significantly higher than the low levels of nutrient salt ran in hydro, which is increasing my doubt that the skimmer pump would create the sized bubbles I'm seeking. However, if the disolved o2 levels are higher than the air pump and stone, then this is still a step forward in efficiency.

Also, yes. I am planning on running a chiller. I live in the northern mountains of Cali so during winter it is unneccessary, but during the summer will be all but mandatory. I may do an initial run and test without one. The temps don't start getting consistently above 70 until March.
 
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Budley Doright

Budley Doright

Well-Known Member
HarryCooter said:
I'm sure it would easily produce enough with that flow rate. Im confident I wouldnt need a venutri at that rate either. Im just trying to go somewhat perfectionist, although I know it is completely unnecessary. This isn't my first rodeo with dwc, but as I've mentioned in other threads I'm in this for the science more than the product. In the spirit of science, the first step needs to be running one of these pumps in a tank with a salinity of 300-600ppm, and testing the disolved o2 divided by 8 vs an air pump with the equivalence of 1 watt per gallon of solution. The recommended salinity in a salt water tank is around 3600ppm which is significantly higher than the low levels of nutrient salt ran in hydro, which is increasing my doubt that the skimmer pump would create the sized bubbles I'm seeking. However, if the disolved o2 levels are higher than the air pump and stone, then this is still a step forward in efficiency.

Also, yes. I am planning on running a chiller. I live in the northern mountains of Cali so during winter it is unneccessary, but during the summer will be all but mandatory. I may do an initial run and test without one. The temps don't start getting consistently above 70 until March.
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I am cut from the same cloth re testing shit and also pretty much the same re temps. I run an underground glycol loop all winter and keep room temps at 75, res temps at 66-67. Mechanical chiller runs in the warmer months and will add a chilled water coil this year, chiller has more capacity than needed for just the res ;). I have, in the past, moved outdoors June 1st but may stay in longer next summer with the new draconian laws coming. And as for the Venturi your right, it's better to have then want lol.
 
M

MASSgreen

Member
Any movement on this experiment? I am looking into adding one of these needle wheel pumps into my single bucket dwc. tired of the PH fluctuations from the airstones.
I have been tinkering with some venturi setups from a water pump, but I'm not sure if it is producing enough small bubbles.
 
kingtitan

kingtitan

Well-Known Member
MASSgreen said:
Any movement on this experiment? I am looking into adding one of these needle wheel pumps into my single bucket dwc. tired of the PH fluctuations from the airstones.
I have been tinkering with some venturi setups from a water pump, but I'm not sure if it is producing enough small bubbles.
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have you tried tap water?
 
Airwalker16

Airwalker16

Well-Known Member
I have a 10gal short storage container that I’ve put 3” netpots through the lid. It’s kikcing ass but I too am still trying to find a solution to remove the air pumps. I want a more silent room.
 
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