Got gas? King Tut in RDWC

Hello again. I'm sorta like Haleys Comet. I come by every so often to find answers then fade out to return later. Well, I'm back and looking for answers with CO2.

I have 2 King Tut plants from Pyramid Seeds. I've grown this strain before but it was in soil.

I'm trying it again in a max effort grow in hydro with gas. I just think I can do better. This is my second grow with gas. Last season was a 18oz plant in hydro and a 12 oz in soil. Pretty cool, but im sure I'm missing some trick of the gas trade. I'm here to talk to those that use gas successfully and pick a brain or two.

My room is in a shed in Southern California. It's heavily insulated with AC, a dehumidifier. I have a 2x2 closet that I grow with heavily composted soil. I usually grow the same strain as the plants in hydro but not today. The strain this season is Dark Phoenix by Greenhouse Seeds. A new strain, but kind of a problem child. Terribly misshapen seedlings, wrinkled as if I grew them in a glove compartment of an old car. But, of the 2 seeds started I got 1 that outgrew most of its issues.

I'm using ChilLED lights in both areas. Over the hydro are 2 500watt fixtures from their Growcraft series and a smaller one in the closet. The shed is set up for bringing air in from the outdoors and removed out with a 8 inch fan in the roof. But I won't be doing this since I'm using gas. Well at least till deep flower

I have an 8 burner CO2 generator... too large for this space, but I bought it for a later configuration of the shed that will double the grow area. I use a repeat timer to turn the generator on and off... no fuzzy logic bad ass controller here. I use a Titan meter to show the gas in PPMs. The gas turns on for a little less than a minute and shuts off for 20. Not a very sophisticated rig but it works ok.

My RDWC system is a repurposed GH aeroponics system (there are actually 2) used as deep water. Including the res. it's about 50 gallons laid out in 2 pots that can grow as many as 14 plants each, but there will only be 2 this season. I cool my water with a fan, no chiller... I can go into that further if you have a RDWC rig but don't want to buy a chiller. My fan will cool the water by more than 20 degrees if the humidity is low. Water comes in by float valve directly from a 300 gallon RO filter.

So that's the bones of this story. I've been growing (on a forum) for about 5 years. Pretty comfortable with growing in general, but I really want to learn all about CO2. I'm looking for a gas growing Jedi to hold my hand a bit.

Questions:
When do you stop using gas in flower?

What PPM numbers do you grow to, and do you change them over the life of the plant?

What temps, humidity, nutrient level ( if you're growing in hydro) and light output in PPFD do you use?

What's the deal with Calcium? I gotta mainline that shit into my plants to get it to work.

Last season I basically had 2 plants. One in soil the other in hydro. Both did very well


While the soil plant did really well, it didn't share the rock hard bud quality with the hydro plant. The buds were very large, but loose. This plant was revegged so it was it's second harvest. The first season the buds were much smaller, but much denser than the second... what do you think happened here? Was it a CO2 thing?

Anyway. I hope this thread finds the right people. I know I'm in the right forum for questions as long as everyone can keep their cool haha. Thanks!

I did a nute change today... to be honest I'm still in the middle of it. One major change is the use of a new Silica. You may remember I bought a new one. MSA Stout from Alchemist. It's about $55 for a gallon, which may sound like a deal if you know mono-silicic acid, but the dose is 5 times larger than other like products so it IS more economical, but not cheap.

The addition of this new additive brought some surprises. First, it's very liquid... almost like water. So it mixes easily. Power Si is almost like pancake syrup and Facilitor is much thicker still. This picture was taken of my mixing Power Si RO water measuring 40PPMs.

This was an older bottle,, so I believe time may have been an issue. But, I ran this test because of these issues in prior use. This new stuff went in without much drama. There was a slight clouding which usually means the additive is reacting to other nutrients, (problem) but still nothing like Power Si. My hydro guy assures me that this clouding is nothing to worry about, but I am very skeptical. There was no huge pH shift after the MSA was added. Any Silica I've used before has had a huge shift. The Potassium Silicate products go up and get more basic, the mono-silicic products dip toward the acidic. There was a slight pH shift and it went in the right direction, but only went to 4.8, no sweat. This could mean a couple things... the people who made this stuff know what they are doing, or there isn't enough of the good stuff in it to move the needle very far. I'm hoping for the first one. Alchemist IS a chemical company. Not some brotha in the shed banging away at various products trying to make something work. I've been using their pure alcohol and 34% peroxide for years. My fingers are crossed hoping for a positive result.

The base nutes and additives are, or will be added in this order and volume. Calcium is from Botanicare and gets a full dose. I don't like adding calcium later if I can help it. Micro gets a full dose. Bloom nute. gets a half dose as does the Grow nutrient. I will add more later once the PPMs go down a tad. This works well because they will get plenty now and then a brand new fresh dose later without ending up with 1450PPMs at the end of the day. For the rest Floralicious, Rapidstart, teas, etc, I can add a partial dose now and more over the life of this nutrient mix. Hydroguard will get 150% dose and more added every week till the next change.

All the finicky products ( Silica, Calmag, and Micro nutes) are in so the rest is easy. I've been thinking of adding Cytoplus from Bioag. It has a bit more Potassium and humates so it's easy on the plants. My rational is it may help jump start the smaller plant, it's definitely slower than the other hydro plant. It doesn't seem to be ailing at all, just slow. But Cytoplus makes a damn mess, so im on the fence.

Hope all is well with you.

A brief video:

I'm curious to hear how you have a fan set up to cool the water. I can't justify 500$ for a chiller and would love some Insight thanks

Yeah, they get spendy, and they put a serious hurt on your electric bill. I got lucky and saw how they cool aquariums sometimes. This method works by evaporation. As air moves across the water it evaporates a small amount. Given the constant action from the fan it can noticeably cool the mass of water. A couple things to know...

It's best if your using a hydro system with a seperate reservoir. DWC isn't gonna work here.

If you live in a highly humid area, or have a hard time keeping humidity down in your grow area this may not work for you. One of the downsides of this method is it can increase you RH. You can vent to an area ( I could vent outside if it ever got bad, but im cool with it, but if the exhaust is venting inside your room it may increase humidity.

In hot, dry conditions my fan can lower the water temp by more than 25 degrees. But usually only 10 to 15 degrees which works just fine for me.

I think it would be easier to show you...
Here's a brief video I made for a friend.

This method is super easy, and scalable. There are tons of possible changes that could be made to improve the cooling rate. I kinda stopped tinkering with it because it works so well. And, if its working too well (Winter maybe) you can use a repeat timer to turn the fan on and off at specific intervals.. My rig is about 50 gallons, not small, really not small for 2 plants.

The bottom line is I grow in a shed in Southern California, it's been 102 IN my room, and no plants died. I will never need to buy a chiller... I think I may need a new fan someday soon though... I hope this works for you. If you have questions I'm here