This would definitely be the case when I think about the general quality of the totes available to me - thanks for reminding me! Okay, so you would use the totes with the ebb & flow with pots in it, filled with leca? Would the tote itself also be filled with leca?
Good to know, I went under the assumption that opaque containers would still get algae, turns out I was wrong.
Noted again and again and again. I will keep it in mind!
Is there any point to placing a submersible low wattage UV light in the reservoir tank if I have that on hand?
Only the pots are filled with grow medium, not the tote.
You’ll still get algae and bio-films that will form, but it will be considerably less on areas that don’t have direct light exposure. There’s really no way to avoid it completely. Algae spores are everywhere, just like yeasts and molds, they’re airborne and there’s no real way to avoid them colonizing and growing in a place that has the right conditions. A little algae isn’t going to hurt anything, but if you allow it to get out of control it will eventually begin to affect your plants.
No… a UV light is not necessary and will not really have any benefits.
Superb! Then it’s time to start buying stuff. Will post more once I start getting things setup or if I have any more questions. Thanks for all the help so far guys, invaluable advice!
@Lucid3y3 I was reading something about feeding etc and I came across this:
Clay pebbles have the least amount of water retention at virtually 0 percent, which means longer feeding times and more frequent feedings. To start, give your plants two 15-minute floods each day.
And it got me thinking - how do you do that when you have an auto-siphon?
I also read that you need an air stone in the reservoir, is this true?
Hydroton or leca is a lot more absorbent than they say. It is not as absorbent as coco-coir, but if you use a medium that holds too much water, you’ll have to be careful about over-watering and root rot. I performed a test once to see how long I could let the plants go without water in leca, and it was over a day before they noticeably started wilting, and 2 days before they looked really stressed. And these were full size cannabis plants in 8 inch pots.
Obviously, the larger the pot, the longer you can go between watering.
Like I mentioned before, when you use leca, you are actually doing NFT, only the nutrient film is on the leca in the pots instead of the bottom of a trough. This means you need to water fairly often. Once every 4 or 5 hours is fine for small plants, and once every 3 to 4 hours for larger plants , and you only need to flood the leca for a minute or 2 each watering cycle, which is about how long it takes to fill one of your bins… this is why I said it’s better to fill the bin slower than faster to get more contact time between the grow medium and the water. This means you don’t need a large pump.
Also, you should always pre-soak your leca for 24 hours before you put it the pots with your seedlings/plants.
The reason I prefer leca is because it doesn’t hold as much water as coco or other grow mediums… it is almost impossible to over-water using leca, no worries about root rot.
Also, roots interact with the grow medium they are in contact with, they tend to increase pH in the root contact zone… so watering more often will help maintain the proper pH balance in the root zone where it is important.
And yes, running an air stone in your tank is critical unless you want your tank to go anaerobic and breed bad bacteria. This is pretty much true for any hydroponic system.
Yeah, somewhere between 800 and 1500 L/hr (200 - 400 gal/hr) should be fine for a 1m x 0.5m bin.
The more important thing to know is what the maximum head-height of the pump is, vs what the height of your highest tray will be… most of those fountain pumps can only lift about 1.5 meters, maybe 2 meters if you use a smaller diameter hose, but that should be just about right for a rack shelf like the one in the pic you posted.
Yeah, the reason I picked the 1500L/H is because the other lower output pumps had a max head-height of 2m, whereas this had 2,5m. Better safe than sorry.
I’m looking at what’s available from the suppliers in Norway and it seems incredibly hard to source a simple bulkhead fitting without it costing $25-30 (which is too much imo), except for this type:
You will not be using that “filter” piece for anything, it’s not needed for a flood and drain system.
Keep in mind that you will need to be able to fine-tune the siphon during the initial setup to get the maximum water level and inflow/outflow just right.
You will need to adjust the height of the top of the “loop” as well as adjust the height of the pickup/intake. And once you have those adjusted, you’ll want to make sure they don’t move or accidentally change after that.
Tuning your siphons will be the most difficult part of the entire setup (not actually that difficult, but it can take a little trial and error). You need to have just enough inflow to make sure there is enough outflow to actually start the siphon working instead of just trickling. So it’s actually good to have a slightly over-sized pump, and make sure your siphon isn’t too big, but still big enough to have more outflow than inflow. While there is some degree of flow adjustment on the pump itself, your inflow/outflow ratio will need to be adjusted by using a valve on the inflow hose.
Also, when selecting hose… do not use polyethylene hose (irrigation supply line). It is not flexible enough and will kink when you bend it.
The best hose is 1/2 inch silicone black hose, it is a bit more expensive than vinyl hose, but so much easier to work with.
No? I’m not sure we’re on the same page regarding the siphon type I’m suggesting here. The bulkhead fitting with the quick connector (first image) will be mounted on the bottom of the tray, with the quick connector pointing downwards. The filter will then be fitted into the connection hole on the inside of the tray, making sure large debris can’t enter the tubing. On the quick connector on the bottom I will then connect the 25mm hose, which will be looped on the outside of the tray, making a siphon, then routed into the tray below on the rack.
I’ll add a valve to the siphons for fine adjustment as suggested.
The hoses the supplier I’m getting the pump from etc. are reinforced and it’s what they sell for hydroponic use, so I’m taking a gamble that it’ll be fine, especially if I combine it with the mount I suggested in my previous post for the siphon half-loop.
EDIT:
It’s exactly like this, except my siphon will be a looped hose on the outside of t he tray and the fill/drain fitting adapter is flush to the bottom of the tray, allowing for all the water to drain:
Ok… yes, that should work. The only issue is that filters can get clogged, if it clogs and reduces or prevents outflow, your tray will overflow when it gets filled
This is yet another reason I prefer leca… pretty much no debris compared with coco or other grow mediums
25mm hose is much too large for a small system like this, you will never get the siphon to start unless you have a LOT of inflow rate… use 1/2 inch hose for everything (13 mm). Remember, fill the bin slowly.
Reinforced rubber hose works just fine as well. I prefer hose to hard pipe for a small system because it allows you to change or re-route things much easier when needed.
The overflow safety as shown in the picture is not a bad idea, but it must have it’s own dedicated hose and can not be tied into the siphon hose obviously because it would prevent the siphon from forming a vacuum I never needed an overflow safety… I just made sure my siphons were properly tuned and made sure the timing on the pump was set to never create any overflow situations. It does take some trial and error and fiddling a bit to get it all dialed in the first time, but usually once you have everything set, you shouldn’t need to adjust it again.
Ohhh, okay. I just went under the assumption of what you said earlier, but perhaps I misunderstood it:
Yeah, the medium will be leca in the pots, I’d better be safe than sorry with the coarse filters if it somehow manages to fall out and clog the drain.
The overflow assembly in the picture is not something I’m looking to implement, I was just using the picture to show you how the filter and bulkhead looked.
I also bought a lot of bed rollers and tested them all in the rack - I finally managed to decide on one. Then I guess I’ll order all this shiiiiet tonight. Progress!
That was a bit of an error on my part… the inflow/outflow ratio will actually not be that drastic. The outflow just needs to be enough so that even if the pump gets stuck on, there will still be slightly more outflow than inflow when the siphon is running so that the bin will not overflow.
Yeah, doubling the diameter of a pipe does not equal doubling of the flow rate in that pipe. Doubling the diameter of a pipe usually means more than doubling the flow rate, even at static pressure.
Should I go with square plastic pots in the tray to maximize the amount of plants I can grow or should I keep them spaced out like the picture you posted up top? I’m not sure what kind of size the containers is recommended for leafy greens, I see some sites state 2" approx. I’m looking to start with spinach and lettuce first, and maybe some radishes etc once I get into the groove of things.
Is there any reason not to fill the whole tray with leca and just drop the pots? I don’t understand the benefit of the pots.
Square or round pots won’t really make that much of a difference, but square pots will kind of lock together a bit better and help prevent each other from moving or falling over when the tray floods, however square pots can be harder to find.
Size your pots depending on the size of the plants that will be going in the pots, but remember, all the pots really should be the same height to prevent the leca from floating out when the tray is flooded. You really don’t want to flood the tray to where the water is over the top of the pots. Like I said before… you want to flood the tray to where the max water fill line is about one inch below the top of the grow medium in the pots. If you use pots that are too small, your pots will fall over, I would recommend nothing smaller than 4 or 6 inch pots. You are not going to be able to make them all fit in the tray nice and neat… the fit will be whatever it ends up being.
Go look at the pictures I posted again. Notice that the flood tray is taller than the pots, this is very important! You want to fill the pots with leca so that the top of the leca is about 2-3 inches below the top of the flood tray. Then you set your max water fill height to about 1 inch below the top of the leca.
This allows you to completely flood the entire root zone of the plants, but prevents the max water fill level from being too close to the top of the tray and causing possible overflows. I can’t find any good pictures or diagrams that explain this, and I don’t have the time to draw one… hopefully you are understanding what I am trying to explain.
The reason for the pots is so that you can remove them from the flood tray to easier inspect your plants, easier harvesting, and for access to cleaning the flood tray. You could just fill the whole tray with leca, but then you can’t remove individual plants, their roots will get tangled with each other in the tray, and you will end up with roots growing down into the drain siphon causing it to clog on a regular basis. Explain how you would “drop in the pots” on a tray that is filled with leca? Leca rolls around like marbles, you can’t just drop pots into a tray filled with leca. And why would you waste all that leca if the roots can’t reach it because the plants are in pots?
What’s preventing the roots from growing into the drain with a pot vs a whole tray filled with leca? Easier inspect my plants how? I won’t be able to pull the plant out of the pot without leca going everywhere, same as if the flood tray was just leca, no pots?
Okay, so my tray is 18cm ~ 7" tall. So the leca would be 13cm ~ 5" tall. The water level would be 10cm ~ 4".
Sorry if these are stupid questions, I’m just trying to understand the pros and cons of various methods and avoid repeating mistakes others have already done.
Yes on this… for reasons that should be clearly obvious over the other picture, especially if you’re doing this indoors and one of your bins is up on a shelf where you might need a step-stool to reach it or even see it.
Stop and sit down… close your eyes… take a few deep breaths… and in your mind see this whole system built and on the rack…
Now try to imagine yourself tending to the plants, having to bend over or sit on your knees to get to the bottom flood tray, or stand on your tip-toes or a step-stool to reach the top tray. Try to imagine having to get to the plants in the back of the tray if they were all stuck in one big pile of leca. What happens if your siphon or the bulkhead gets a leak? Are you going to destroy half your plants digging out a big pile of roots and leca all dumped in a tub, or do you just pull a couple of nice neat pots out?
You really need to think ahead about all of the possible maintenance problems you might run into , and then try to design as much of them as possible out of the system before you start building it.
Try to imagine having to treat an algae bloom in that big pile of leca… same thing… you’d have to dig it all out and kill your plants instead of just pulling a few pots and spot treating them.
You might need to shuffle some plants around occasionally so they all get the same amount of light, or to offset them leaning one way too much from phototropism, or because you want the maturest plants at the front of the bin where you can harvest them with the younger plants moved to the back where they will be undisturbed until ready. Pots can also be individually covered to keep light from reaching the grow medium to prevent algae and reduce evaporation. Designing a hydroponics system is not only about providing the ideal environment for the plants, but also about providing the easiest way to cultivate and harvest for the grower.
You can adjust that a bit if needed… nothing is really set in stone.
The goal is to make sure you can flood the entire root zone every watering cycle, but never overflow the flood tray.
However you manage that is up to you.
My biggest “fail-safe” is that I have my system sitting inside the shower stall of my RV camper… so even if it overflows, nothing is going to get severely damaged because it will all just run down the shower drain (this is why I didn’t install overflow risers in my flood trays, but you may want to consider it as a fail-safe).
I still spent the better part of 2 or 3 days testing and adjusting and fine-tuning my pump and siphons and everything else before deciding it was safe to put plants in there and let it go… and then I still had to do some more fine-tuning over the next few days to get it really dialed-in. It’s a process… it takes time, it’s not all going to work perfectly on the first… or even the second or third try.
These are all very good points. Sitting down, deep breaths and slowing down hasn’t been easy since I quit inhaling plants a couple of months ago, apologies. Pots it is!
In regards to the overflow protection, I’m trying to think (yes, trying… ) The overflow protection will be one of these, adjusted for my desired height:
This looks good, you have your siphons cascading down to each bin, and you have a separate dedicated overflow line for safety. Your inlet line can simply hook over the side of the tray with a U shaped piece of pipe that has a barbed connector at one end and just open at the other end that goes in the flood tray. I’ll post a pic of the one I made later so you can get the idea. Also, you don’t need to buy those special stand pipes for the overflow drain, you can simply use a piece of PVC pipe with a threaded fitting on one end that screws into the bulkhead. Your overflow pipe should be at least 1 inch taller than your siphon to make sure the tray can fill all the way to the top of the siphon so it will start before the water reaches the overflow.
I already have the bulkheads and the opening on the inside is not threaded, it’s a tight press fit (this is not the water seal, this is just to ‘add accessories’ to the bulkhead, such as the coarse filters etc.) I’ll measure the inner diameter tomorrow and see if it matches PVC dimensions, if not I’ll just order them, they weren’t especially expensive here and I have to order some other parts from them anyway.
Yeah, show me some pics of that U-shaped pipe. I was thinking of just drilling a hole in the top side of the tray, add a watertight grommet and put a barbed elbow on the hose and push that through.
Sitting down, deep breaths and slowing down hasn’t been easy since I quit inhaling plants a couple of months ago, apologies. 
Pots it is!
) The overflow protection will be one of these, adjusted for my desired height:
