Would this work?

medicalgrowman

medicalgrowman

Active Member
I am currently putting-together a TopDrip/DWC system
to grow 1 plant under scrog in my grow tent under 250w CMH.
I have read that optimal solution temps for oxygen uptake
is 65F. And that even going up to 73F can lower oxygen uptake
and cause root rot issues. I am thinking of making an external
cooling reservoir that I will place outside the tent.
Put a waterpump
to circulate water from reservoir to dwc bucket.
Add small frozen water bottles to cool the water solution.
Add an AirStone and AirPump to add Oxygen.
It would have 2 somewhat large black tubes connecting it to the dwc bucket.
It would have a thermometer inside.
I have seen similar systems, but they seem to be placed at
a different elevation than the dwc bucket. Why is this necessary?
Thanx!
 
MRHOOD

MRHOOD

Member
that would work but you will need an air pump in addition to this. To get the nutes from a separate res to the DWC bucket you will need a water pump that moves water/nutes rather than an airstone that blows air into and airstone at the bottom of the bucket. So you could recirculate the nutes from the outside cooler with a separate pump and then you'll still need an air pump and stone running into the DWC bucket to keep the oxygen flowing. Good luck, I hope this helps.
 
medicalgrowman

medicalgrowman

Active Member
If you re-read what I said.
I did say that I plan to use a water-pump for circulating the solution
and the air pump is just for making air bubbles via the airstone.
The air pump is not intended to help circulation of the solution.
The air pump is solely intended for adding oxygen to the solution..
I hope that is clears it up for you now. Thanx!
Do I need to elevate either the dwc or the reservoir?
or can they be at the same level?
 
Weedler

Weedler

Well-Known Member
Just place frozen water bottle into the reservoir and replace every 12 hours when you check on the plants... I do this and it keeps my temps in check. If you want to build a cooling system I have posted something up before but never saved it do a search for DIY Cooler? Heck I have no clue lol
 
Neumann

Neumann

Active Member
medicalgrowman said:
Do I need to elevate either the dwc or the reservoir?
or can they be at the same level?
Click to expand...
The height in both containers will be the same if they are level. The height, above or below level, of the reservoir will determine the height of the liquid in the DWC unit. As your pump drips, I assume it's pulling liquid for your recirculation? If I was building that type of system, I'd have a 2 part stacked reservoir with a float valve in the bottom. It's a pretty simple system, if you need help with details just ask.
 
Heisenberg

Heisenberg

Well-Known Member
Just to clear up your concept a little. Water temps effect the amount of dissolved oxygen the water can hold. Higher temps will actually cause the roots to resperate a little faster, creating a situation where there is not only less oxygen in the water, but a greater demand for it as well. This is why it's recommended to have at the very minimum 1wt air pump per gallon of water. If you double your res size by adding a cooling chamber, you are doubling the amount of water which you have to oxygenate, so add air pumps accordingly.

Personally I would just inoculate with beneficial microbes, keep the water very oxygenated, and forget about temps. My buckets stay around 73-75 with no problems.
 
medicalgrowman

medicalgrowman

Active Member
Heisenberg said:
Just to clear up your concept a little. Water temps effect the amount of dissolved oxygen the water can hold. Higher temps will actually cause the roots to resperate a little faster, creating a situation where there is not only less oxygen in the water, but a greater demand for it as well. This is why it's recommended to have at the very minimum 1wt air pump per gallon of water. If you double your res size by adding a cooling chamber, you are doubling the amount of water which you have to oxygenate, so add air pumps accordingly.

Personally I would just inoculate with beneficial microbes, keep the water very oxygenated, and forget about temps. My buckets stay around 73-75 with no problems.
Click to expand...
Thanx for that info! What would be a good, easy to add source of beneficial microbes?
Thanx!
 
Neumann

Neumann

Active Member
medicalgrowman said:
Thanx for that info! What would be a good, easy to add source of beneficial microbes?
Thanx!
Click to expand...
If I can make a suggestion, I'd get a handle on one concept at a time. While beneficial bacteria in a reservoir may be a technique you want to explore in the future, I would make my focus understanding the principles of the mechanical style you want to work with, then get your growing under control where you understand nutrients, lighting and the rest of the basic pieces. Once you are comfortable with the process, then start introducing changes, that way you will be able to judge for yourself whether it's helping or not. You need a baseline before you start experimenting.
 
medicalgrowman

medicalgrowman

Active Member
Neumann said:
If I can make a suggestion, I'd get a handle on one concept at a time. While beneficial bacteria in a reservoir may be a technique you want to explore in the future, I would make my focus understanding the principles of the mechanical style you want to work with, then get your growing under control where you understand nutrients, lighting and the rest of the basic pieces. Once you are comfortable with the process, then start introducing changes, that way you will be able to judge for yourself whether it's helping or not. You need a baseline before you start experimenting.
Click to expand...
With respect. I am wanting to make sure that my roots don't rot and get adequate oxygen.
What concept are you suggesting I master before dealing with that? Shall I put that issue on hold
until I master whatever basic concept you think I should learn?
I have an issue I want to address, and I'm looking for productive suggestions to correct my issue.
Not condescending lectures.
 
Heisenberg

Heisenberg

Well-Known Member
Neumann said:
If I can make a suggestion, I'd get a handle on one concept at a time. While beneficial bacteria in a reservoir may be a technique you want to explore in the future, I would make my focus understanding the principles of the mechanical style you want to work with, then get your growing under control where you understand nutrients, lighting and the rest of the basic pieces. Once you are comfortable with the process, then start introducing changes, that way you will be able to judge for yourself whether it's helping or not. You need a baseline before you start experimenting.
Click to expand...
This isn't bad advice, however if you brew up a microbe tea and use it in a DWC, you can't really mess things up. You can't over apply the tea, and the tea will never burn the plants or anything like that. The benefits are tried and true and best of all, it only costs pennies to make the tea each time.

I am assuming that you are using synthetic nutes. In this case, the main benefit from beneficials is protection from disease. Pythium is just one of the nasty things DWC roots are prone to. Bennies will do an excellent job of keeping disease at bay.

The issue of dissolved oxygen is not always that important. At 75f, the water can still hold about 8ppm (at sea level) which is above the minimum of 6ppm. Also, roots breath when they make momentary contact with air bubbles. The main reason to keep the water cool is to make it inhospitable for harmful microbes. So if we innoculate with bennies we can effectivly forget about water temps. The exception would be grow rooms that use C02 and push their room temps into the 80's, in which case the water is probably about 78 and approaching the 6ppm threshold.

Benneis will also discourage algae making it unnecessary to have a completely lightproof res. Then there is the many benefits you get from increased water/nute uptake, increased root mass, ect. If you want the recipe then click the link in my signature. It may sound laborious to make the tea, but it's actually very easy and very cost effective considering the benefits. When I started making tea I believed the only benefit was disease prevention, since then I have learned that the benefits are actually very numerous.
 
medicalgrowman

medicalgrowman

Active Member
Heisenberg said:
This isn't bad advice, however if you brew up a microbe tea and use it in a DWC, you can't really mess things up. You can't over apply the tea, and the tea will never burn the plants or anything like that. The benefits are tried and true and best of all, it only costs pennies to make the tea each time.

I am assuming that you are using synthetic nutes. In this case, the main benefit from beneficials is protection from disease. Pythium is just one of the nasty things DWC roots are prone to. Bennies will do an excellent job of keeping disease at bay.

The issue of dissolved oxygen is not always that important. At 75f, the water can still hold about 8ppm (at sea level) which is above the minimum of 6ppm. Also, roots breath when they make momentary contact with air bubbles. The main reason to keep the water cool is to make it inhospitable for harmful microbes. So if we innoculate with bennies we can effectivly forget about water temps. The exception would be grow rooms that use C02 and push their room temps into the 80's, in which case the water is probably about 78 and approaching the 6ppm threshold.

Benneis will also discourage algae making it unnecessary to have a completely lightproof res. Then there is the many benefits you get from increased water/nute uptake, increased root mass, ect. If you want the recipe then click the link in my signature. It may sound laborious to make the tea, but it's actually very easy and very cost effective considering the benefits. When I started making tea I believed the only benefit was disease prevention, since then I have learned that the benefits are actually very numerous.
Click to expand...
Thanks for that info!
Would "Great White" be a good microbe supplement for this purpose?
 
Neumann

Neumann

Active Member
medicalgrowman said:
With respect. I am wanting to make sure that my roots don't rot and get adequate oxygen.
What concept are you suggesting I master before dealing with that? Shall I put that issue on hold
until I master whatever basic concept you think I should learn?
I have an issue I want to address, and I'm looking for productive suggestions to correct my issue.
Not condescending lectures.
Click to expand...
See, there I go trying to help and sounding like an asshole. I thought because you didn't know the basic concept of RDWC you wouldn't realize that more oxygenation of the water would ensure against root rot, if your temperatures go higher, add more oxygenation. I've done multiple grows with RDWC and have never used or felt the need for beneficial bacteria and have never had root rot even during a temperature spike of 80F .
Sorry for bothering you, good luck.
 
Heisenberg

Heisenberg

Well-Known Member
medicalgrowman said:
Thanks for that info!
Would "Great White" be a good microbe supplement for this purpose?
Click to expand...
Great White is perhaps the best microbe mix out there, but get the soluble mycogrow powder from fungi.com. It IS great white but its only $6 an OZ. This product would take the place of both aquashield and ZHO in the tea recipe.
 
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