Is AISI-302 stainless steel good for the reservoir with nutrients?

Indoor Growing Hydroponics
#21

Which direction does your PH drift?

If it drifts downward, start at 6.1 and let it drift to 5.5, if it drifts upward start at 5.5 and let it drift up to 6.1.

The state of the plants is they are not uptaking a nutrient (main suspects potassium/Mg), the differing info in the charts leads me to want more solid info before I would say “Be at X PH”, so I would cover all the bases and over a few days cover all the range between 5.5 and 6.1.

If your plants do not show recovery after a week, you do not have a PH issue and you have another issue. Mine was excess metals leaching into the solution causing lockout of certain nutrients.

I suspect RO water is more open to leaching stuff from the environment than plain tap water, possibly due to osmosis or some chemical thing that makes it more reactive (chemistry is not my hot subject). Either that or shop-bought CalMag is pants and does not do what it says on the tin.

I am still chasing down the exact cause of this particular def.

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#22

I changed the nutes and my new plants dont show any deficiencies at the moment. Only the old ones. So i think I damaged the old ones too much and maybe there was something in their cubes.

#23

Often, you won’t repair damage already done. New growth is where to check. Is the new growth on your old plants good?

I also found that new plants in my system took a little time for metal toxicity to show, on the order of about 10 days.

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#24

Ahhh I dont know what to think about my old plants. They are looking all kind of colors and directions. But they seem to yield and the leaves on the buds look good. I will see how much they will yield. And the new ones are looking pretty good.

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#25

I have a very similar issue with mine that started when I got my RO unit. @anon32470837 also had the same issue when he got an RO unit.

Regarding yield, I found no impact on yield even with quite bad necrosis. The opposite in fact, I had 1.3GPW under HPS in 11 weeks including veg time.

I am in the process of figuring out what to do about it, the next thing I will be trying is a wider PH swing, once I rebuild my PH sensor and get a new dehumidifier that does not have an ioniser built-in as they drastically affect the circuit I use for measuring PH and make the readings meaningless.

I have already tried ever-increasing amounts of CalMag, as well as individual bottles of calcium and magnesium also in increasing amounts, to no effect.

If there is not a lack then something else is causing the def. The next obvious culprit is PH.

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#26

interesting. I was handling the first plants pretty rough. It is my first hydro grow and switched from co2 with no air cooling ( temperature on the last day up to around 45 degree celsius) abruptly to cold external air with no co2 (down to 10 degree celsius in the night). I even damaged some plants so badly I had to remove them and a lot of plants stayed pretty small and thin all their life. Also I think I fucked up the nutes a bit in the process.

In that process I selected a couple of plants for mother plants which survived everything with almost no damage. (The best 10% percent). Then I took many clones from them (again around 150) These new plants dont show any signs of problems… I just hope these plants will have a yielding genetic. Some of the clones that I selected seem to grow aggressively. They increase in size four times after inducing flowering (only 1 to 1,5 week rooting first). They even grow very close (maybe 6 to 8 inches) to the 600W double ended bulb and the leaves dont seem to change. Just the buds get bigger…

So I think with the batch of selected plants, I can’t say if I got the nutes now right or if it is just more robust plants…

Maybe you can do a test grow without the ro water?

btw how is ionization of the air affecting the measuring of ph in the nutes? is the ions ‘leeching’ from the air in to the nutes?

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#27

Personally, I grow indoors with a variety which was crossed to be grown outdoors. It has amazing growth, branches a lot without topping, can handle very high humidity (RH% 90+) without risk of mould, and continues to put out roots strongly well into week 6 of flowering.

Forced evolution is a great way of selecting plants. Treat them cruel and whatever survives can handle it.

Regarding PH, the way that a digital PH meter reads PH is by detecting the incredibly tiny differences in potential between your nute solution and a fixed reference solution (the liquid inside the PH probe). It measures the changes in the number of ions crossing a glass (or plastic) barrier.

As you can see, having loads of rogue ions floating about in the air and nute solution would make your readings way off. It also seems to have permanently affected the internals of the IC on the circuit I use to measure, probably by overloading some internal section which is incredibly sensitive and short-circuiting it, essentially with a relatively high static charge or similar. This would still, to us, be a very very tiny charge but it would be far too much for the PH circuit. I first noticed this effect when I used a floating pond ultrasonic mister, the ultrasonic process ionises the mist…

I would consider doing a run without RO water if I were getting reduced yields. As it is, the damage seems mostly cosmetic although I suspect I actually do have reduced yields from the amount possible with my system but the increase from running RO offsets that.

I will instead just try to figure out the true problem and then see if yield increases as a result.

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#28

what you mean by contamination? At that time I never used bleach in the reservoir. Maybe it had something to do with that.

#29

thanks for that … been years in industrial settings …I know what a check valve is never seen a non-return. If you don’t want a return you just pipe it away in my head. lol

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#30

The terms are often used interchangeably. Though, here are a couple of representative illustrations:

Non-return valve:

image [1]

Check Valve and or non-return valve:
image [2]

The second illustration show a spring to ensure closure and a specific ‘crack’ pressure to open it back up. They serve a similar purpose but you generally can’t claim backflow protection for a swing-gate or ball non-return valve (NRV). A check valve will have a bunch of parameters ensuring performance such as crack pressure. An NRV generally does not provide that information. E.g. if a local ordinance demands backflow protection, technically an NRV likely will not satisfy the requirements.

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#31

My familiarity is more along the lines of backflow prevention. I have seen both in use. Though both were termed check valves even if that was not concise.

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#32

Yeah, it’s one of those things that’s mostly minutia and you’d only worry about the difference for critical application where dangerous things could happen (or perhaps by law).

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#33

As someone who once pointed out to his contractor boss that the panels required copper bus bars. It pays to read the specs. And I never was licensed he was.

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#34

They are both check valves. One is a swing check valve and the other is spring operated, otherwise referred as a non slam check valve. They have their uses in pump assemblies. End suction centrifugal pumps. They prevent water hammer whereas swing check valves increase water hammer.

Any quick closing valve needs a water hammer arrestor or else you can break soldered joints the thrust is so hard. Underground you would use thrust blocks and mechanical joints and use the flanges to attach threaded rod from a horizontal to a vertical. Commonly seen on domestic water services 4" and larger. Well 3" as well but ductile iron is hard to come by at 3" and as a result more expensive.

#35

Systems where one water circ pump serves as both hot or cold water (heat or a/c) supply was what I was thinking about with the hinged one. And yes you usually had to worry about hammering.
The spring ones in pressurized circulatory systems such as hydraulics and refrigeration and AC ( liquid lines that are on a hot gas defrost come to mind)