If you're running a mixture of LED lights that range in quality from "I think they're probably okay" to "they might be pretty good," and you don't have at least 60 (actual) watts per square foot... and/or your garden temperatures are less than about 89°F (with your exhaust fan off), adding supplemental CO2 is not going to help, IMHO.
Hydro sounds pretty complicated to me. Every time I read something on it someones having a problem. Because I work a lot of OT & don't have the time to make sure everything is right all the time I've been avoiding it. Hydro sounds like you really have to be on top of things 100% of the time with no room for mistakes or you lose your crop. Maybe I'll try just one of those 4 or 6 plant Hydro Tubs I've seen to find out 1st hand how hard it is. I hate to invest too much till I know I can handle it.
Can you visit your garden at least once every two days?
Go to Home Depot (or Big Lots) and buy a plastic tote of 20- to 23-gallon capacity. Swing by ChinaMart, go to the pet section, and buy an air pump, some long air stones, and enough tubing to connect them together while allowing you to place the air pump higher than the top of the tote (so if the power fails and its check valve is faulty, you won't return to find all of your nutrient solution soaking through the ceiling in the room below, lol). Also buy the "Aqua-Tech Submersible Pump for Aquariums" (it's an aquarium power head, states as much right on the front of the box) for $22.82. The combination will provide enough aeration for that size reservoir.
You'll also need: one LARGE Solo cup and enough expanded clay media (aka "clay balls," sold under the brand names of Hydroton, Geolite, etc.). Also a piece of 2"-hole poultry netting (aka "chicken wire") approximately 4'×4' in size, and something to connect it (rigidly) to your tent. Cut/saw/melt/gnaw a hole just big enough to stick the Solo cup in (tightly) so that only a couple inches or so sticks out, in the middle of the tote lid. Drill or otherwise create as many ¼" holes in the part of the cup (including bottom) that will be below the tote lid as you can without getting them so close together that they become big holes.
Install air pump, 'stones, and power head. It'll probably be easier if you drill a hole for the air line, and another one just large enough for the plug on the end of the power head's cord. Whoops - you'll also need a young cannabis plant, heh. You can use a seedling, but it's probably better to use one worth a set or two of actual leaves. Rinse off all the soil you can from its roots. Take your time and be gentle. After you get most off, you can swish it around in a bowl of room temperature for a while. Don't worry about not getting 100% of it off; you won't be building the kind of setup that pumps nutrient solution through small-diameter lines.
Got your soon-to-be monster plant ready? Good. Fill the Solo cup with the expanded clay media and plant roots. If you can get any to go through some holes, great. If not, that's okay. Now jam/twist the cup into the hole in the lid. Attach lid to tote.
Congratulations! You've just constructed your very own DWC setup, and at a cost that's considerably cheaper than most "professional" ones. If you use the poultry netting to turn it into an actual, legitimate SCROG, it's capable of producing a pound of bud per harvest. Fill the tote (reservoir) with nutrient solution. It doesn't really have to be FULL - but if it's not in contact with at least one root tip, you'll have to pour nutrient solution through the cup at least a couple (more is better) times per day until it is. Once at least one root tip gets into the solution, you can stop helping. BtW, the root system will destroy the cup eventually. By then, the poultry netting will be supporting the plant.
Okay, here is where I'll be a bit hypocritical: Buy a set of General Hydroponics Flora series nutrients (FloraMicro, FloraGro, and FloraBloom). I stopped recommending GH products a while back, but that's because Scotts MiracleGro bought the company, through its Hawthorne Group shell entity. The products are great - and great for a beginner. If you have "hard" water, there is a Hardwater FloraMicro component available that contains less calcium. You might end up needing their "CalMag" product, but not immediately.
Oh, wait, you still have half a tent empty. Head back to the store and pick up a 4 cubic foot bag of perlite. That's more than you'll need, probably, but it doesn't spoil. Now start buying two-liter bottles of Mountain Dew or that stuff that Coca-Cola sells in green bottles that tastes like death with extra corn syrup,I forget what it's called. You can use clear bottles, but you'll have to paint or tape them to keep light out of the root zone. Put a hole in it, a couple inches from the bottom. Fill each one with perlite and a rooted clone. If they go straight into flower, you can really pack them in. Hmm... No, have to do that in a separate tent, because your SCROG plant needs some time to turn into something that you'll need a saw to cut loose at harvest. Well, you'll think of something to put in there. Meanwhile, here's a little thread on the pop bottle hempy concept:
Hello everyone, It's been a long time since I've ran a journal here. I just started a large SOG grow today so I've decided to journal it here for you. I have 3 Snow White(NLXCinderella99) mothers in my veg room along with a 50 site aero cloner. I just transplanted the first 16 rooted clones...
www.420magazine.com
That is a passive hydroponics setup, which simply means hand-watered, not actively aerated.
There are other setups, but those are cheap and simple (but productive). The big hempy thread shows other container ideas. Buckets are popular. Dollar Tree sells little black trash cans for a dollar that are, IIRC, 5.9-quart capacity. Et cetera. There are lots of other nutrient brands. That one is just inexpensive (although not the cheapest in existence), clean, stable, and has been around since the late '70s or thereabouts. If it's good enough for NASA, lol...
You'll also need a decent pH meter, but I assume you have one. If not, the Milwaukee Instruments pH56 worked great for me. It's not the cheapest, but it's waterproof (might come in handy
), has a replaceable probe, is accurate, auto temperature compensation (and shows the temperature of what you're checking), and has "automatic" two factor(?) calibration. If you don't know how to properly do the initial prepping of, store, and/or calibrate a pH meter, search for a thread or post one, and you'll get help with that.
Hydroponics is easy. It just scares people who don't know anything about it because, well... they don't know anything about it, lol. Some even say that if a person has never grown anything other than what they run a lawn mower over once a week in the warmer months, it's better to start the gardening journey via hydroponics.
Oh: print out a copy of Mulder's Chart (search routine should bring it up) and one of the deficiency/toxicity pictorial threads. Also, there's a chart that tells you what's happening - and what to do about it, if anything - when your nutrient solution is rising/falling/static and your EC is rising/falling/static. It's not necessary, but might be helpful (and educational to look at).
