Some opinions needed for an ebb and flow setup

[Red October]

Hey ya'll, I'm doing my first foray into an ebb and flow setup and would like some opinions and critique if anyone can see issues arising before I start.

Proper ebb and flow tables are very expensive in my country so I'm planing on using 4ft x 4ft growers trays. These trays don't have slots for the water to travel so I'm planning on setting them at an angle so water will still be directed to the outflow pipe and I either want to use gravel or clay stones at the bottom of the tray so my containers won't sit in any water that hasn't drained away completely. I'm planning on trying to make it more automated, so the inflow pipe will sit as flush as possible on the tray and the outflow pipe will be raised up slightly higher to ensure the water level fills the tray enough to reach the pots and circulate water back into the container while the pump in on so the pump doesn't run dry. Once the pump switches off the inflow pipe will become the effective outflow pipe as it'll sit more flush to the tray allowing for most of the water to be drained away.

The design works in my head but this is my first time doing this and I'm worried I'm overlooking something. The stands I'm going to build will have a solid top so the trays don't sag and allow water to collect and stagnate in the tray and I figure I can use 1 reservoir for 2 trays. I'm going to use a 50/50 coco and perlite mix but I'm tempted to use a bit of compost in the mix as I figure it will help keep things more stable in the substrate but I'm worried this could lead to pathogens being an issue.

 

[TheDarkStorm]

I wouldn't use compost, it stays wet too long and there is a risk of it not being sterile and keeping sterile. You want to take advantage of the ability to use multiple wet and dry cycles in your lights on times. Just remember to wash your growing medium thoroughly and use something to filer and keep clean the water around your in and out fittings. I used to use a pile of slightly larger rocks just over the inlet and grow directly in the trays in hydroton, the whole tray would turn into one huge slab of roots. I dont see you having issues with your plan, just use a good quality feed as it keeps your reservoir more stable and keep the reservoir covered up if possible. It can get really humid using a tray system so make sure your plants are not too cramped and have a good air exchange/air circulation system. Apart from that it sounds like you should be good. Oh its all so a good idea to have your reservoir a minimum of at least double the capacity of your trays if not more, they start drinking fast you dont want it running dry on you at any time.

 

[Red October]

Many thanks man, I didn't even consider the additional humidity the extra surface area the substrate would cause, maybe using gravel wouldn't be a bad idea as it's not porous?

Would you mind going Into a bit more depth about the wet/dry cycles vs the lighting cycles.

 

[Lightmeup209639]

A peek at my growop

 

[Red October]

The polystyrene boards are a good idea, thanks man.

 

[Smoggy]

Top flush weekly to dissolve salts accumulating from evaporation at surface_ will lead to stem burn

 

[f-e]

Flood/Drain's advantage comes from its 'roots out' design. It's all about the air.
The tank can last up to 10 days if maintained correctly. 2 days would be very wasteful.
Roots blocking the drain is a real issue. I used mesh to section off the corner where the drain was. This way air pruning stopped the roots blocking the pipe, and I could see this in action. The roots seem hell bent on getting out that drain.
A bit of heat can deform plastic, in order to get the drains plumbing fitting a bit lower.

I don't like tables. The volume of water required makes it inefficient when scaled up much beyond a couple of cutting trays. If you look at a bucket system it's much more efficient, as you don't flood the space between the plants. It's still a lot of water being chucked though. The barrel must hold all that, and enough to drink. Buckets make a lot of sense when it comes to packing it all away to. Tables are really for sea of green using densely packed small pots.

 

[unnamedmike]

Excuse me for deleting my answer, I answered without reading your question well ... My previous answer was referring to ebb & flow systems with arlite, or little "hydrophilic" substrates.
My experience was positive, the only reason I do not use this system is the need for a huge water tank to fill pipes and pots.

If it was my system, I would not use coco or pearlite. I think the coco would be saturated with excess water. And, I usually have problems growing in coco, if I do not allow 20% drainage when watering (nutrient blocking) Its not advisable to reuse the water growing in coco, nor is it advisable to mix organic "things" with coco. The pearlite floats.

Pic from a million years ago, and a million miles away, a tray full of hashplant#13

Aquaponic, pure pearlite.

 

[Red October]

.

I'd love to hear your opinion Mike.