First hydro setup and grow

HELP!!! I’m very green(no pun intended) and I have a few questions about lighting. I’m planning a 4 bucket 5gal RDWC with 27 gal res. Running 2” PVC pipe and valves with 3/4” return. I’ll be growing in a built grow room, that I’ll section off for germ/cloning/drying. I’ll be starting from seed. There are soooo many different light types. I believe I want to go with LED. Cooler and cheaper to work with. Do I have to have a separate light for shoot-root growth/vegetation and flowering. Is there a single wattage light system with a dimmer that would work for both veg and flower? What is PPM and does lighting have anything to do with it? You see lighting systems on Amazon and there very inexpensive compared to other, is there a big different in quality and longevity? I will have plenty of other questions as this project grows. Any help would be valuable and very much appreciated.


Hey welcome to forum

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@dbrn32 @MattyBear @garrigan62 @TDubWilly @WickedAle these guys should be able to answer your question


If you are growing in a large room you want your lighting to be modular to accommodate multiple heights that different plants will have. Your flower room will have to be very light tight during darkness unless you decide to run autos(not recommended as autos are like herding cats to make them flower. They all have different schedules). You will have to decide how you want to break up your footprint. Each plant takes 2x2 at a minimum with DWC. For a 4 bucket system I have a 4x4 although I would prefer a 5x5 if I had the chance. We can make recommendations for lights depending on how you want to break up your veg and flower footprints.


PPM(parts per million) is a measurement of dissolved solids refereeing to nute strength and has nothing to do with the lighting.


Welcome to the forum!

We generally target a specific light density to maintain optimal daily light integral. The formula for what you want is total radiometric flux over area in square meters.on ambient co2 target a ppfd average of 600-800 umols per second. Outside of maybe some differences in reflection, none of the rest of that stuff will really have anything to do with lighting requirements.


Lighting will have a huge impact on the nutrient loading based on the amount of photons in the grow space. Increased use of cal mag too.

RDWC is not ideal for multiple strains with differing nutrient requirements. You might be better off with straight DWC so you can tailor the nutrient load for the individual plants.

As @WickedAle said; lights ought to be adjustable for height and power. Most of the Amazon lights marketed are not that good. They use pretty outdated tech and use deceptive marketing–pretty much ALL of the lights. HLG is a better place to look and you can, if handy, DIY your own lights. You’ve already met our light-bringer haha.


@Myfriendis410 is correct with this statement as the more the plant grows the more nutrients it will require. I was simply differentiating terms and concepts for easy understanding.


Kinda figured, but thought I’d be anal and clarify that haha.


Better off running a 1to1 RDWC than a DWC

This is true, but we don’t want to make it seem like we adjust lighting levels to nutrient concentration. My comment based more on a 4x4 grow space has same lighting requirements no matter what you have in it. 1 plant in a soil grow or 25 in a hydroponic grow.

From there, as long as you keep up with co2 and water, more light will boost levels of photosynthesis and thus nutrient uptake as well. I figured original ppm reference was directed more at co2 actually.


That’s kinda what I figured about those lights on Amazon. At this point I’m wanting to grow 2 strains. A strong sativa. I have people who suffer from PTSD. I also will try a highly recommend inda hybrid. Also have people with Insomnia. I’ve been reading about all the different seed strains offered by ILGM. Thank everyone for all the input.

Thanks hope to learn a lot.

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Welcome! Sounds like your on your way! Oh and these guys and gals will help guide you to the right light!

I grow Crystal for my brother who is 100% VA disability: pain and ptsd.

It’s good for insomnia too, but so is Gold Leaf and White Widow and a bunch of others. People with insomnia should really look at using edibles along with vaping/smoking.

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That’s mostly what I offer… easier for the first time elders and non cig smokers edibles… and tincture…

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Welcome to ILGM and to our community
any way dbrn32 is our go to light guy.

but here is some info on PPM AND P H


Knowing What Your Plants Are Eating and How Much They Can Handle
October 20, 2016 by Devin Martinez
One big question growers ask is “Why are my plants suffering even though
I used all the right nutrients, feeding cycles, lighting cycles, and adjusted
temperatures and conditions to their absolute best?”
That’s because their pH and PPM levels are off, making it difficult for your
plants to eat. pH refers to potential of Hydrogen ions in your water, which
will determine if your water is too acidic or has too much alkaline in it.
PPM (parts per million) refers to the concentration of minerals and soluble
matter in your watering solution.
Correct pH and PPM levels are the backbone of any grow, and will be the
difference between a healthy grow and a huge waste of time and money.
pH Levels
Simply put: the right pH level will create an environment where your plants
can absorb nutrients quickly and easily, leading to a better harvest.
Nutrient-rich water is filled with elements that are helpful to your plants.
However, if those elements can be broken down properly those same elements
can harm your plants.
pH levels is important to understand because the right level will determine
the quality of helpful bacteria in your water that help break down elements,
helping the metabolic rate of your plants. How? In two ways:?

When pH levels are too low (pH level of around 5 of lower), heavy
metals like iron and aluminum change and can become toxic to your plants ?

If the pH level is too high (pH level of around 6.5 or higher)
elements like calcium and phosphorus can’t be broken down completely, which
will hinder the growth of your plants
This change in properties is due to how acidic your water is or is not.
You’ll want your plants’ nutrients to be a little acidic otherwise they can’t
break down, but too much acidity and your nutrients can become toxic.
So remember: pH too low= toxic to your plants, too high= growth decrease.
That’s why you want to have the perfect level of acidity in your water,
which will be around 5.5-6.0
Typical pH Levels ?

3.5 and below: Root Damage ?

4.0-4.5: Poor Nutrient Uptake ?

5.0-5.4: Good pH Level ?

5.4-5.8: Perfect pH Level ?

6.0-7.0: Acceptable pH Balance ?

7.5-8.0: Poor Nutrient Uptake ?

8.5 and Above: Root Damage

Note: Soil grown plants tend to need a little bit higher of a pH than hydroponics
because soil retains and releases certain elements to your plants at different times.
However, both hydroponic and soil pH levels should stay within the same optimal range
of 5.5-6.0 pH.
PPM Levels
PPM (Parts Per Million) refers to concentration of the particulates in your feeding
From minerals found in tap water to natural elements found in your nutrients, your
job is to make sure that the PPM levels in your water solution are on point so you’re
not under- or over-feeding your plants. While it’s an easy concept to understand on
the surface, it’s a little more complicated when you have to adjust elements.
Now, pH plays a huge factor in PPM levels because even though you may have the correct
PPM reading, some of the particles- and the concentration of those particles- can be
harmful for your plants.
For example, let’s say your plants need to be at a PPM level of 700. You mix your
solution and you get a PPM reading of 700 but your pH is around 4.5. That means that
the majority of the available food for your plants is likely to have lots of heavy
metals in it, which will quickly toxify the plant. You’ll need to adjust the pH level
of your solution to make sure you’re not toxifying your plants.
“But won’t that throw my PPM levels off because you’re adding particles to your feeding
solution?” It can, and that’s what’s so tricky about PPM and pH levels: When you adjust
one you usually have to adjust the other, which can be simple or a huge pain depending
on the water and nutrients you’re feeding your plants.
Common PPM Readings

These readings reflect the PPM your water should have at a given stage of growth
? Seedlings: 100-250 (nutrients aren’t really needed here, hence there’s not a
lot of particles needed)

? First Half of Vegging Cycle: 300-400 (this is usually after you transplant,
which still don’t require many nutrients)

? Second Half of Vegging: 450-700 (you’ll start giving your plants more nutrients
at this stage)
? First Half of Flowering: 750-950 (your plants will be eating more as they grow,
so they’ll be taking in more nutrients)

? Second Half of Flowering: 1000-1600 (this is when your plant’s eating the most,
especially if you give it additives)

? End of Flower, Entering Harvest: As close to 0 as possible (this is when you’ll
be flushing your plants, so you don’t want there to be a lot of particles left over)
Adjusting pH Levels
When it comes to feeding plants there’s two ways of looking at it: homemade or store bought.
Same goes with balancing your pH: you can either purchase a pH buffer from a store or you
can use ingredients you can find around your home or in the grocery store– but both come
with their advantages and disadvantages.
Homemade pH Buffers
? Advantage: If pH levels are low you can use a little citric acid or even white
vinegar to help bring your water’s pH down. When you need to raise your pH levels you
can use a little bit of baking soda in your solution and bring those readings back up.
This will cost you less than picking up a buffering solution.
? Disadvantage: The issue with using these solutions is that they don’t work for
very long. You’ll find yourself having to add a little lemon juice every other day, then
having to use a little baking soda to even things out. Moreover, we’ve also heard of
growers using these ingredients and seeing severe spikes in pH, which if not handled
properly and quickly and bring your grow to a halt.
Premade pH Buffers
? Advantage: Most hydroponic companies out there will have pH buffers, usually
called . They’re much easier to use than citric acid or white vinegar mixes. They’re
designed raise and lower the pH of your water while keeping your water’s pH levels
balanced for longer than it would be without them.
? Disadvantage: As we’ve always mentioned, easier usually means more expensive.
These solutions usually won’t cost you an arm and a leg, but they’re definitely something
you can’t simply make at home and will cost some money.
Adjusting PPM Levels
Before you start adjusting your PPM levels, you’ll first want to make sure your tap water
is ready to feed your plants. That means you’ll want to adjust the PPM of your base water
before you start feeding it to your plants Now, any time you add anything in to your watering
solution, you’ll be adding more particles in to it, so keep an eye out on your PPM levels at
all times.
? To rid your water of too many particles you can use things like a carbon filter or a
reverse osmosis machine to clean your water. However, many growers agree that most tap water
has helpful minerals (like calcium and magnesium) that actually help plants.
? During and after the vegging stage, your plants will want more out of their feedings
so filtering isn’t really necessary. That’s why we recommend only using filters at the
beginning of the plants life when low PPM readings are needed
? For a quick fix when PPM’s are high just add a bit of fresh water with a good pH
level and watch them drop. Filtered, pH’ed water is great when things get a little too
much in your reservoirs.
? When readings are low it’s usually time to feed your plants. When you add nutrients
to your feeding solution your PPM’s will go back up, and when your PPM’s and pH’s are in
balance your plants are going to be happy and healthy.
? Just remember that these readings need constant adjustment, so if you haven’t been
keeping a close eye on your plant’s PPM and pH levels there’s not better time to start than now.