Single or multiple reservoirs

[ChrisInTheTropics]

My missus and I have decided we're going to build up a fairly large hydro setup in the garden, ultimately with 4 or more NFT rigs (i.e. frames with pipes running back and forth with 60-80 pots in each), plus some tower-stands.

This would normally mean maintaining half a dozen or more reservoirs, but I'm mulling over the idea of a shared reservoir for most of the rigs (nutrient preferences of plants allowing).

On the positive side it means less measuring and checking, larger volume of water so easier to keep stable PH/EC/etc levels, fewer (but beefier) air pumps, fewer UV lamps, the reservoir can be buried in the shade rather than close to each rig in the sun and mains electricity only needs to be supplied to the reservoir area.

On the negative side it risks killing a lot more plants if something goes wrong with the shared reservoir/nutrient/etc, and needs some pipes to go from the grow area to the reservoir area.

On balance the shared reservoir sounds much more appealing, it just seems a cleaner solution, with self-contained units eg. for tomatoes that apparently need a different enough mix of nutrients to be worth having a separate setup for them.

Are there any downsides I've not considered ?

 

[AltTerra88]

It seems you have a lot of projects going on!!
The shared reservoir definitely has its merits, especially for stability and maintenance!
I think one downside you should consider is the potential for disease transmission.
If a pathogen gets into your shared reservoir, it could quickly spread to all connected rigs, potentially wiping out a large portion of your plants.
With individual reservoirs, I imagine an outbreak would be more contained.
Also, you have to consider how to ensure consistent flow and pressure across all rigs from a single pump, which can get tricky with varying distances and elevations.

 

[ChrisInTheTropics]

Aye, a poisoned well scenario is certainly my main concern. On reflection since I posted the original message I've concluded that the shared tank is probably my only practical option.

With the sun and air temperatures being so high, I really do need the reservoir(s) both in the shade and buried up to the neck if I'm not to spend a fortune on cooling and/or half my day changing ice packs, and with the geometry of the garden and the sunny bit being entirely paved, I'm pretty much stuck with a 6-8 metre gap between the green stuff and the reservoirs.

Isolating the rigs from each other's nutrient, as well as needing the extra tanks and pumps, would mean having several pairs of pipes running into and out of the heat. One pair I can get away with, several and the back garden will start looking too much like an oil refinery and my missus won't be amused

The other thing is that I will have to make sure the plants that share a tank like the same levels of nutrients. I plan to keep the tomatoes separate as I read they need more something (nitrogen possibly).

So a shared tank it is, and nutrient purity/quality/paranoia will need to be an obsession, but I guess it should be anyway !

Yes, the consistent/equal flow is something I've been wondering about too, with the current single tank, 2 grow rig setup I added ball taps to the main pump feed and each of the 2 after the split and with a good bit of adjusting the pump output and those 3 taps, got a nice flow rate that suits both sides (one has 2 rows of 12 large pots, the other has 12 rows of 10 tiny little pots and is more of a seedling nursery).

Now though, I'm proposing a 4 way split each into sets of 6 big tubes that will probably grow to 6 sets, so that might get complicated and possibly impossible to get it to a really optimum setup without perhaps some smaller tanks and mini-pumps to do the final push into the rigs (but then that puts mains electricity back into the middle of the garden , which I was trying to avoid !) - or the smaller tanks being sited above the plants somehow and feeding by gravity but the ugly factor of buckets up in the air would probably count that out !

One thing I'm not doing with the current rig is having a place for the water to go if it doesn't go to the plants, i.e. the water currently goes down one or the other pipe, through a tap, to the plants. I'm guessing it'd be easier to control if there was also a pipe that fed directly back into the return, with a (pretty much nearly closed) tap on it, I bet that would make it easier to fine tune the other taps/supplies.

 

[Galinda]

My missus and I have decided we're going to build up a fairly large hydro setup in the garden, ultimately with 4 or more NFT rigs (i.e. frames with pipes running back and forth with 60-80 pots in each), plus some tower-stands.

This would normally mean maintaining half a dozen or more reservoirs, but I'm mulling over the idea of a shared reservoir for most of the rigs (nutrient preferences of plants allowing).

On the positive side it means less measuring and checking, larger volume of water so easier to keep stable PH/EC/etc levels, fewer (but beefier) air pumps, fewer UV lamps, the reservoir can be buried in the shade rather than close to each rig in the sun and mains electricity only needs to be supplied to the reservoir area.

On the negative side it risks killing a lot more plants if something goes wrong with the shared reservoir/nutrient/etc, and needs some pipes to go from the grow area to the reservoir area.

On balance the shared reservoir sounds much more appealing, it just seems a cleaner solution, with self-contained units eg. for tomatoes that apparently need a different enough mix of nutrients to be worth having a separate setup for them.

Are there any downsides I've not considered ?

Well what can I say except well done. You seem to have thought this through way better than most people who are starting out. Only thing I'll add is maybe consider backup power for the shared system, since one outage could mess with everything.

 

[ChrisInTheTropics]

Thanks and case in point, I just had a pump fail; not looked into it yet, just spotted it after dinner, the tubes have a good depth of water so not an emergency, I'll flush some nutrient through to refresh it before I go to bed and sort it in the morning.

 

[ChrisInTheTropics]

This is the result of me putting together the 3 things I have going together, with one reservoir. They were separate items but I wanted to clear the space where they used to be for the big reservoir, so moved them into one place and got them sharing the same probably inadequate reservoir

The idea is to learn about how water behaves when it gets split up, and bent round corners, restricted with taps etc. to inform the main project.... and to generally have a play with the idea.

Not intended as a permanent thing, mainly sealant rather than glue so I can rip it apart and reuse the parts easily.