Fertilizer injector plumbing
 

I've got a few questions about potential irrigation plumbing possibilities

Currently I mix RO and nutrients in a tub and use an irrigation pump to hand water plants in a few distinct areas, 4 of which are SH and vary by light/temperature and currently for plants in traditional medias that require a bit more attention to moisture levels.

In the past I have run RO water from a pump to misters, that was in a single area before i split things out to more lighting and temperature zones. I've since expanded the areas and split into more culture zones and I am now tackling the irrigation.

I would like to set up a few zones controlled by irrigation valves and the pump on a relay. I would like to pump from my RO reservoir and inject my nutrients. I want to be able to:

Mist RO, perhaps in 2 different control zones

misting for general humidity

misting for mount moisture, also for some carnivorous plants (a subset of the humidity zone)

Drench RO or nutrient in 2 different watering zones

SH zone with frequent (3-4 times/week

potted traditional medias (1/week? I'd have to see)

I would like to use the single pump. I know how to set up a fertilizer injector bypass when I want to use just RO, but that would use an additional 3 irrigation valves.

Question 1: Could I simply just use a NC 24V solenoid on the injector's concentrate input tube that will energize when I want to program a fertilizer cycle, otherwise it's just RO?

Question 2: Though hardly requisite for my purposes (at least if I ditch the carnivorous plants from the plan), I'd like to understand typical practices for draining lines so for example that I don't have piping full of nutrient solution when i want to do an RO drench. Additionally the misting lines would only ever be scheduled for RO, but nutrient solution may be filling the line leading to the zone manifold . Could I open a "low point" valve between the injector/bypass and the zone manifold, as well as all the zone valves, in order to clear the line when I'm done fertilizing or misting each of the areas?

Question 3: does anyone have a schematic or description of something similar they've done, or feedback on this plan? Would I be better just dedicating a separate RO-only pump for misting?

In my automated watering system in PA, I had a shallow well pump with bladder tank that was between the RO tank and the fertilizer metering pump.

I used straight RO for a fogger by merely tapping into the line in between the pump and the metering pump. The fogger was controlled by a humidistat that opened and closed the fogger's solenoid valve.

I had a "Y" downstream from the metering pump. One side went to a hose with a shutoff valve for hand watering, the other leg had a solenoid valve for controlling the overhead "rain" nozzles, when I wanted to water remotely.

100% of the irrigation water contained 25 ppm N fertilizer, and instead of using zones for different watering frequencies - which could be easily done with independent solenoid valves - I just adjusted my potting media - if any - so that everything could be watered at the same time. I had plants in S/H culture, bark, sphagnum, mounted, baskets with- or without any number of different media, you name it.

If the weather was sunny, the plants got watered more frequently than when it was gray. At 25 ppm N, watering daily (or even twice a day) was no burden on any plant.

I think the idea of self-draining lines so you could run pure or fertilized water is more work than its worth.

The self-draining lines that I used to have burst open and messed up a lot of the surroundings, not worth it. I had to call a plumber and it all went downhill from there too cause I'm pretty sure that the company was a big scam. They didn't have insurance and the guy wanted to look as he hurt his foot because of some hazard that I had there and wanted to get money insurance off of me. I have no idea why they all don't have good external plumbing insurance, that's something I look for any time I hire a plumber now.