maybe some yucca extract to make the water wetter??
1 Like
Interesting idea!
At this point, Im thinking this may be more of a user error thing… still re-reading…
1 Like
I may have discovered the problem. Apparently, these fabrics come pre-treated with some sort of water proofing or coating of some sort. Parker (the Membrane guy) recommends cleaning them with a TSP based de-greaser. Gonna have to make a trip to Home Deopt.
3 Likes
Would this stuff be any use http://www.solcoat.com.my/product-category/polyster-nylon-screen-printing-fabric/
Thats the silk screen material I am going to use to keep roots out of my drains. A long time hydro user on another forum says it the only thing that has worked for him. He says you may have to clean it off part way through a grow though.
I have some and thats one of the fabrics I used in that test above. It wicks a lot better than the ripstop nylon and flows water through itself very fast. BUT - the mesh size is much larger than the ripstop. I was thinking of using the silk screne instead of the ripstop, but the larger mesh size now has me worried a bit.
I have been re-reading Parkers membrane book and his patent application and some more details are starting to stick.
-
Apparently, even the ripstop nylon isnt 100% against roots. That makes me worry about the silk screen.
-
He is fanatical about the roots NOT sitting in water. He only wants the thinnest film of water on the roots, BUT you still need enough water.
-
Fresh air is critical.
He points out that a thin film of water will reach O2 saturation much much faster than a large body of water. The speed with which water reaches saturation, or the O2 absorption rate, is based primarily on surface area - all other factors being equal.
Lets say you have 1 cc of water with a 1 sq centimeter of surface area = 1cmx1cmx1cm. It will have some fixed rate at which it absorbs O2. Lets just say it takes 1 minute for that single cc of water to reach O2 saturation/equilibrium with the air in a given space.
If you take that same 1 cc of water and spread it out over a 10 sq centimeter area (1cmx10cmx .1cm thick), it will reach saturation 10 times faster. Spread it out over 100 centimeters of area (10cmx10cmx .01cm thick), and it will reach saturation 100 times faster.
His point is that a very very thin film of water on the roots, will absorb O2 and stay near the saturation point almost instantly - or at least stay saturated or close to saturated all the time - as long as there is fresh air in the root zone. That will allow the roots to take in O2 as fast as they need it.
So his main point is providing that very thin film of water along with fresh air on a constant basis. Any time the roots are sitting in more water than that thin film, they are not getting as much O2 as they could.
Even if the water is saturated by airstones, etc, it takes time for the O2 to move through a thicker layer of water. Longer than it takes for O2 in the air to enter a thin film and reach the roots.
That theory makes sense to me, but at the same time, I think maybe he is going a bit over board in minimizing the amount of water. At one point in the book, he talks about adding another barrier to keep roots out of the lower nute chamber, but then he pokes holes in that barrier to let more water through. He mentions that at those holes, the roots seem to grow faster than elsewhere. That seems to tell me that a little extra water is not bad.
Long story short - Im considering using the silk screen instead of the ripstop - but Im worried about root penetration into the nute chamber…
2 Likes
I am impressed by your dedication, hope all your efforts pay off for you. It’ll be interesting to see how you get on. Me i like to keep things simple, which is why i like constant circulation bucket setups for hydro. As i get older i have less energy or inclination for experiments but i can maybe sometimes help others with theirs. A
2 Likes
LOL Yup - I think I am beginning to see why this ‘future of hydroponic crop production’ has not quite taken over the hydro world just yet 
This is definitely a technique for someone who is willing to tinker, fiddle, and mess around with small details, materials, etc etc.
Its not that any part of it is really hard, but the small details do seem to matter - a lot.
2 Likes
Ive started the harvest on my soil grow! That is going to take me another couple of days to finish at the rate Im going, but Im going to have to commit to some final details.
I expect to start cutting holes in my bench and get this project officially started by mid week.
I have been waffling, but I think Im going to go ahead and give the meniscus technique an honest try.
3 Likes
We had a couple of unseasonably warm days last week, and I really wanted an excuse to try them anyway, so I ordered 10 of the peltier cooling plates. I only have room for four of them on the heat sink, but I figured Id get extras in case some didnt work or quit. Turns out I needed more than the ten I ordered.
Total junk.
Only 3 of them seemed to cool much when I bench tested them with a 4th working so-so. The rest barely cooled at all or actually got hotter on both sides. ALL of them had warmer and colder places in them with some cooling on one part and heating on another part of the same side.
I went ahead and mounted the four best ones to a good sized heat sink with thermal paste and wired those 4 up to a power supply, and they dont work worth a damn. The hot side gets really hot, but the cold side wont drop more than 1 to 3 degrees at most when first powered up. After a minute at the most, the temp goes back up to room temp or above. Over all, the cold side heat sink only dropped maybe 3 deg at the start, before heating back up, while the hot side went up almost 30 degrees even with a fan.
Im bummed.
2 Likes
That sucks man, I’ve heard similar stories about those Peltier plates. Apparently, the cooler you can keep the “hot” side, the cooler the “cold” side can get. Also, check the polarity because that flips the “hot” and “cold” sides. They are just not that efficient.
2 Likes
I think the main problem here is I went toooooo cheep 
I know this technology can work very well with quality units. Electric ice chests, aquarium coolers, etc all use this technology. You can buy quality modules from Mouser, etc but they cost 10x’s as much.
At this low price point, I suspect all you get are factory rejects or crap clones, etc.
1 Like
Im starting to prep my tent to change over to the hydro setup and I had a nasty thought - how screwed am I if my last crop went hermie and made tons of seeds?
Does that mean I have pollen all over the inside of my tent, lights, fans, ducting, carbon filters, etc, etc, etc?
Am I going to have to sterilize everything or is there a simple solution or???
1 Like
Water kills pollen. Clean everything and you are good to go. 
2 Likes
Whew. I wont be able to get everything wet, but I can re-clean several times before I start the grow.Hopefully, any pollen stuck in ducting or hiding in cracks will come out during my trial runs.
1 Like
How do you clean the carbon scrubber?
When I clean my carbon filters I break them down, remove the charcoal and clean the metal pieces than add new charcoal. I don’t really think you can clean the charcoal.
Pollen is also only viable for about a week unless refrigerated or frozen. I wouldn’t stress about it too much, by the time you are flowering, the pollen should be “dead”.
2 Likes
Ok, that is very reassuring. It will be several weeks before my next grow is flowering.
My carbon filter and scrubber are both DIY. Basically take a home heating system air filter, mount it so it sits horizontally inside a box, then cover the filter with aquarium activated carbon, add ducting as needed. I wasnt planning to clean them, or changing out the carbon, until after this next grow. They were not 100% effective in controlling odors, but they did reduce them a lot. At times during flowering and especially towards the end, I was sure they had quit working based on the smell in the house, but when ever I opened the door to check the plants, it was obvious they were actually taking out maybe 75-90% of the smell.
1 Like
sometimes by slowing down the air flow you can further reduce odors.
1 Like
Carbon can be cleaned and reactivated, but is it worth it?
Cleaning carbon can be achieved via 5 gallon bucket and water, dump your filters carbon out into the bucket, cover with water and stir until it stops bubbling (this is offgassing and generates just a little heat, don’t boil your bucket). Dump the water, do it again, just to rinse the carbon off real good.
Now the tricky part. you need to heat the carbon up to at least 500F until all the water is driven out. This is gonna stink real bad as this further helps to release whatever has been absorbed. Think two skunks in a fight kinda smell. A good propane bbq grill can achieve this without using a whole bottle and you’re outside so you won’t stink up your house.
You will lose some of the carbon in this process, so have some extra on hand to replace loss.
Tbh, unless you have a huge scrubber, it’s probably cheaper to just replace with new carbon.
1 Like