How many bubbles for a DWC?

OregonMeds

Well-Known Member
Looked through the links. Did not see anything that looked like anything over maybe one pound per plant ie about 450 grams which is about what seed suppiers state for a yield for a squat meter. His plants seemed to occupy about a square meter.
That would put his yield per watt more in line with traditional standards that's for sure, but don't forget DD's system is strain dependent also and he's taking that into consideration and spent time seeking out the best plant that yields the best in his given space and made everything as ideal as he could.

He's not forgetting anything.
 

fatman7574

New Member
Fatman can you explain what it is that happens to the nutrient solution in hp aero that makes it so you can't re-use the stuff, and what if any theories you may have on how that can be overcome. Also would any of those issues translate to a system that used a somewhat high pressure high volume jet, but nothing on the small size you're working with? Theoretically of course.
It is not so much that you can not use a recirculative system it is more the case that it is just not such a good choice of methodology. Heigh pressure and air atomized sytsems use a very low EC nutrient mix. So low that you must use waterfor your nutrient mix that is zero TDS or very near that level. When your working with a nutrient TDS of 250 to 650 ppm there is not a lot of chance that you can provide a good nutrient balance by just water top offs and added nutrients to raise yor TDS daily. Consider if you are not using much calcium. It has a large electric potential as it has a +2 charge. It would take very little time before you had a huge amount of calcium and calcium compounds in your resrvoir and little of anything else. Basically you end up quickly without TDS being nutrients you don't need and few of what you do need.

When you compare that with the low cost of the nutrients for a low TDS solution and the fact that for a 1 meter square chamber you are only spraying about 4 gallons per day and that the little bit of water that the plants do not use is almost void of nutrients it just isn't really practical to consider a recirculation system over a recirc system. Then you do not have to also worry about sdjustments to pH either with drain to waste. You need to consider with chambers of 1 square meter or less your only spraying a few ml per every one to two minutes. When your using nozzles that only add up to 2 to 5 gallons per hour total if running constantly but your only running them for about 1 minute per hour that is only 24 minutes per day. ie drain to waste just makes the most sense.
 

squarepush3r

Well-Known Member
I've been doing some testing with my new DO meter, and come to the conclusion that the DWC isn't effective because it raises DO levels (it doesn't really above average levels, it prevents it from dropping if anything), but DWC is effective, because the actual air bubbles passing through the roots, and root hairs, and getting caught up in the root pores and such. So its the actual air bubbles, not DO levels.

make sense?
 

fatman7574

New Member
I've been doing some testing with my new DO meter, and come to the conclusion that the DWC isn't effective because it raises DO levels (it doesn't really above average levels, it prevents it from dropping if anything), but DWC is effective, because the actual air bubbles passing through the roots, and root hairs, and getting caught up in the root pores and such. So its the actual air bubbles, not DO levels.

make sense?
Never heard anyone conjecture that before.

Preventing the DO from dropping is raising the DO. To saturate above normal saturation levels however takes alot of bubbles or a lot more surface turbulence than is neded just to maintain normal saturation levels. If you do not believe this possible go just down stream of a water falls, or water rapids and check to see if the water is not higher than before the water fall or rapids. Go to a dam and check the DO level below the water spillway and compare it to the DO level for the water before it enters the spill way. Check the water DO level in a hot tub or whirl pool that has not been running for few days, then turn the pumps and air on let it run for a few hours and check the DO level. All the above example will start at normal saturation levels for the water temps but after the turbulance and air etc the water will all have a saturation above normal for the water temperature. If a buuble takes longer to reach the surface then more of its oxygen enters the water. This means if the bubble is stuck to a root more oxygen will enter thwe water from the bubble. That is true. But the oxygen will enter the root s throughthw water at thesame time rate as it would enter the water without being stuck to the root. It is a matter of time the bubble is inthe ater anfd the size of the bubble. Little bubbles have more surface area per volume so they have more surface area in contact with the water so more oxygen makes it into the water.

This will probaly insight some negative response but plants roots do not need all the oxygen we put into the reservoirs usually. Plants roots do have a limited need for oxygen.

The problem is the water must maintain high enough DO oxygen levels where ever it is in the entire system to prevent anerobic bacteria from multiply in any area of the system. That means the water in any part of the system such as after the roots extract their oxygen needs must also supply the oxygen needs of any other aerobic bateria in the system and still have a bit of dissolved oxygen in it before it gets back to the reservoir where is has its DO boosted again by a pump or airstones etc.

If at any point the oxygen level drops to near zero or some say below 2 ppm anerobic bacteria will start growing. And where does this have the greatest chance of happening? Any place where the waters flow is slowed down and is also in contact wih the roots or any organic substances that can feed bacteria, ie dead root particles and such. This happens whether water sits stagnant around roots in aero tubes, in cracks and crannies (espeaially if they trap old dead root apartcles there. Yes parts of ther oots systen are always dieing and being replaced by new roots).

This low water DO problem also exists whereever roots are in contact with any surface and appears stuck to that suface. That root area in contact with the surface gets a limited DO in that area so it therefore so aerobic bacteria can develop there. That is the reason that root mats should be used in the bottom of NTF and small aero tubes as it keeps water moving between the roots and the bottom of the trough or tube. That is also the reason that troughs, tubes and tables should have a good drop in elevation to the drain side so that none of the waters is depleted of DO before it makes all the way through all the roots, cracks and crannies. Even ebb and flow tables gain by the root mats. This greatly lessens incidences of root rot in all systems where the roots would others wise be in contact with a surface.

This whole situation is magnified by the fact that the beneficial bacteria and the aerobic bacteria grow/multiply better at higher temperatures and use more O2 so compete more with the plant roots for the O2. In a battle between aerobic bacteria and plant roots for O2 the bacteria will win. So we really supply most of the DO we do create in the reservoirs to prevent aerobic bacteria from developing in large numbers around roots areas.'

Some people simply run lower DO and keep both the aerobic (O2 loving) bacteria and the anerobic bacteria (O2 hating) from ever reaching large numbers.
 

fatman7574

New Member
so fatman, what is your take on tubular nft/aero hybrids?
Will they work. Yes. Are they a great choice. Not really. Chamber aero is better. Very large tube aero is real good if you make your own tubes so as to make them say about 32 inches tall and 12 inch wide. That means one 4 foot long tube per each FRP panel. You can grow sog or large plants on 12 inch wide tubes. Two tubes wide for two 250 watt lights, 3 tubes wide for one 400 watt light, 3 tubes wide and 1.5 tubes long for two 600 watt lights and four tubes wide for one 1000 watt lights.

32 inches of hanging white roots in an aero beats the hell out of a small tube aero with a few inches of hanging roots with the rest of the roots being rotting brown roots laying stacked up in zero DO water. It does not take many roots before they star stacking up on top of each other in a 4 inch round tube. That is why a 4 inch square tubes works a little better than a round tube. A little more spread out room.

Trough NTF is OK for SOGS that are budded out immediately from rooted clones without any vegging. NTf is really only for plants with very small root systems. MJ has a large root system. They can be made to work well with a combination system like you suggest as long as you uses some silk screen or root mat in the bottom of your troughs.

Try to get troughs/gutters as wide as you can find. The idea is that you want as thin a layer of roots piled up as little as possible. That means no large plants, butt a butt load of small ones. Large plants tend to develop to much root rot to make it well through budding as their root mass is too big for small troughs.

The mat or silkscreen allows water to get under the roots so both the top of the roots and the bottom b get good water flow over them. If the rot layer gets to thick root rot will start up and you will see your roots start to go from white too brown. The flat bottom gutters work better than round small tubes/pipes as they give the roots more flat space to spread out so they do not pile up as thickly. Plus it allow for the water to come in contact with more of the l grater outer area of roots.

I am really surprised more people just don't make table troughs for NTF. Just through up a table out of a sheet of ply wood on some saw horse with one a few inches taller than the other. Nail a 2" by 4' every foot and across one end. Get a caulking tube of ceiling tile adhesive and some thick vapor barrier plastic film (visqueen) put some small dabs of the ceiling tile adhesive everywhere and put the plastic down so that you basically have four troughs cover bottom, side walls with and the end plus leave enough to wrap under the bottom of the end with out the cross piece.

Use a piece of gutter to collect the water coming off the table. Four Wide troughs. This will provide wide enough trough s for larger plants with larger roots system and because the roots cam be spread out across the full trough. For a lid ust pick up a FRP (fiber reinforced panels)panel at home Depot. They are 4 foot wide and are either four foot or eight foot wide. The ceiling tile adhesive remains soft for a long time. It is about the only adhesive that sticks well to the plastic. It is really thick when cold so putting it on top of the hot water heater makes it a lot easier to get out of the tube.
 

plumsmooth

Well-Known Member
MaJor Breakthrough I just stretched the Soaker Hose and getting like three times of more the air flow maybe 5X. The surface break and droplets have to more than make up for lots of small bubbles? Not to mention I have exposed roots between inner bucket (net pot equivalent) and water level. I am looking for that surface break in a few places to coat these exposed roots with constant droplets! Also my new 20 watt pump must have been having a lot of back pressure with brand new un-stretched soaker hose? The same thing must happen with air stones: Very inefficient for a strong pump and maybe even bad for the pump. I was loosing my mind earlier think I had bough a bad brand of soaker hose. Then I thought it was the elbows or the placement of the 2 air lines on the soaker hose!!!
 
Last edited:

Lowfruit

New Member
1 watt of pumping power per gallon of solution.
I think it was a guide or seedbank that recommended that as a good average. Of course if you have a large bubblestone that requires more pressure, long tubes and such you might go for a little more.
 

Lowfruit

New Member
Found source, best to read for better context. :)
As a general rule, you should get an air pump that can supply at least double the litres per hour of the volume of your reservoir. For example, if you have a 100l tank, get a pump that can supply 200l/hour. Know that an air pump costing you no more than a few euros will likely not last a lifetime, so get the backup pump as well. And while you’re at it, also get some more air stones. It’s always better to be safe than sorry!

Choosing the correct air pump will help to achieve the best results when growing hydroponically. Investing in a good pump will help you avoid common DWC issues and provide enough pumping power to operate your setup correctly. First of all, we suggest investing in a high-quality pump to avoid overheating issues. Hydroponic air pumps often get too hot and alter the temperature of the nutrient solution. Several factors can cause this including poorly made, cheap pumps that generate too much friction. Using a powerful pump alongside a small nutrient reservoir can also cause heat to build up. As well as investing in a high-quality pump, you also need to select a model with the appropriate power for your reservoir. You can work this out simply by aiming for 1 watt of pumping power per gallon of solution.
 
Top