Mars Hydro 5-Gallon DWC Hydroponic System - Continuous Feed?

[Sativa1970]

So still wondering, and I probably missed it, does this system I have classify as a rwdc since it is in fact recirculating, even though it doesn’t have an external reservoir?

Multiple plants in different containers being fed from one res is RDWC. One plant in a container, without a second res is DWC. A second expansion tank that just increases res volume is still DWC. These are all recirculating systems. Nonrecirculating example would be coco drain to waist.

My plants are using 4 gallons of water or MORE per day.
5 gallon bucket IMO is not big enough for the reservoir size .

That is a serious drinking problem! Sounds like your temp or humidity may be off. I veg in 5 gal bucket holding 4 gal of water. When they hit 2 foot tall and 2.5 foot wide they drain the bucket in a week. I then move to flower with 20 gallons of water per res. They stretch to 4 foot wide by 5 or 6 foot tall. They still drink less than 4 gal a week.

You need 2 gallons of res for every foot of plant. Bigger res is better because it is more stable. I agree 5 gallons is no where near big enough. I also think 4 square foot is not a big enough space to grow a plant. Yet, that seems to be the popular advertised trend.

 

[Ke0ncp]

Ok so here is the “mod” I have made to these buckets so far.

I drilled 2 holes on the lids so that the air tubes go through them instead of the ones on the side. This allows me to lift the lid off to a secondary bucket so that I can remove the reservoir and clean it. Then easily replace everything back to normal.

The way they have it all of the air tubing goes through the top side of the bucket and you can’t remove the lid/net that way.

I was thinking of putting a ball valve at the bottom on the side of the buckets for easy draining but the above pretty much takes care of that and leaves less opportunity for leaks!

 

[Ke0ncp]

That is a serious drinking problem! Sounds like your temp or humidity may be off. I veg in 5 gal bucket holding 4 gal of water. When they hit 2 foot tall and 2.5 foot wide they drain the bucket in a week. I then move to flower with 20 gallons of water per res. They stretch to 4 foot wide by 5 or 6 foot tall. They still drink less than 4 gal a week.

I was thinking the same. I go through a gallon a day in my SIPs right now using HP ProMix, so little to no absorption and my 5 gallon buckets do just fine.

You need 2 gallons of res for every foot of plant. Bigger res is better because it is more stable. I agree 5 gallons is no where near big enough. I also think 4 square foot is not a big enough space to grow a plant. Yet, that seems to be the popular advertised trend.

Yeah I think with these buckets, for me, it is a great way for me to jump into DWC with a premade product that is fairly affordable. This gives me the opportunity to see if I even like this style of growing without investing the time and money into a DIY set up, though now I know that’s it’s pretty simple stuff.

If it turns out I love DWC then I will build out something with a larger reservoir for sure. My friend has one of those really cool conical 36 gallon reservoirs but he also spent like $200 on just the res. Not my cup o tea. I think $20 at the DIY store for a plastic tote works fine for me.

If it turns out DWC is not my thing then that’s fine I can pass these buckets onto another local grower for them to try out.

I guess my big concern was how much work is this going to be with these buckets and I think I found my answer. And with all things in life, and especially grow styles, everyone has a preference as to the right way to do things. There are some absolutes and then there is everything else

 

[Sativa1970]

DWC is less work but more technical end of the grow medial. I run my hose through the top but only an air stone no drip ring. Salt deposits on the ring and hydro tone lead to me abandoning that part with no negative effects on the plant.

Get another black bucket from DIY store. Mix your nutrient in that bucket. Lift the plant and lid, setting on the new res bucket. The less you move it the less chance of damaging the plant. That lid is going to get top heave fast.

You will know when the res is too small. Wild swings on your meters and constant refilling/changing. If you need to go to a bigger res a black tote works fine. I cut a 10 inch round hole in the lid. Transfer the lid over just like with the buckets. In flower I use a 30+/- gallon tote. To the bottom of the basket holds 20 gallons. 2 gallons per foot is you minimum limit, but 4 gallons per foot is max stability. So 20 gallon res is good for a 5 to 10 foot tall plant. That 4 gallon res is going to start fighting you at 2 foot.

 

[Ke0ncp]

If you need to go to a bigger res a black tote works fine. I cut a 10 inch round hole in the lid. Transfer the lid over just like with the buckets.

This is such a great idea and easy too!

But with the weight of the plant do you have to reinforce the tote lid?

In flower I use a 30+/- gallon tote. To the bottom of the basket holds 20 gallons. 2 gallons per foot is you minimum limit, but 4 gallons per foot is max stability

Only asking because I don’t know, but why would you not just start off using your final res?

 

[Sativa1970]

Most of the weight is the water and roots bearing on the floor. The plant itself isn't that heavy but it has leverage. I use steriite totes that have a raised pattern on the lid and lid latches. No strength issues at all. Catch them on sale for around $15. I used a cheap $5 tote first time. It worked but it was a bit flimsy. Lid never broke but it did lean a bit. I put a light over the hole and just use it as a cloning chamber now.

I veg in3-5 gal bucket for 5 weeks and then flower in the 30 gal. First reason is space. I run perpetual grow so my veg space is cuttings, clone starts, early and late veg plants. All crammed into 24 square feet. In flower each plant gets a 4x4 area. 3 gal is for small starts with a weak nutrient mix for there first week. 5 gallon full strength takes them to 2 foot and ready for flower. Less nutrient and space wasted. When I transfer them to flower, they are 2 foot wide like the tote so no wasted space. I add 4 gallons of veg and 4 flower to start the stretch. Once past stretch and flower starts I top it up with flower mix. 4-5 weeks later I pump it dry, dump a few gallons of straight PH water in, to rinse, then pump that out and refill with flower nutes. Harvest week 9-10 and repeat.

My back doesn't like to lift all that water any more. Picked up a fountain pump and a length of tubing for $20. At 8lb per gallon it was my best investment in DWC growing.

 

[Delps8]

Most of the weight is the water and roots bearing on the floor. The plant itself isn't that heavy but it has leverage. I use steriite totes that have a raised pattern on the lid and lid latches. No strength issues at all. Catch them on sale for around $15. I used a cheap $5 tote first time. It worked but it was a bit flimsy. Lid never broke but it did lean a bit. I put a light over the hole and just use it as a cloning chamber now.

I veg in3-5 gal bucket for 5 weeks and then flower in the 30 gal. First reason is space. I run perpetual grow so my veg space is cuttings, clone starts, early and late veg plants. All crammed into 24 square feet. In flower each plant gets a 4x4 area. 3 gal is for small starts with a weak nutrient mix for there first week. 5 gallon full strength takes them to 2 foot and ready for flower. Less nutrient and space wasted. When I transfer them to flower, they are 2 foot wide like the tote so no wasted space. I add 4 gallons of veg and 4 flower to start the stretch. Once past stretch and flower starts I top it up with flower mix. 4-5 weeks later I pump it dry, dump a few gallons of straight PH water in, to rinse, then pump that out and refill with flower nutes. Harvest week 9-10 and repeat.

My back doesn't like to lift all that water any more. Picked up a fountain pump and a length of tubing for $20. At 8lb per gallon it was my best investment in DWC growing.

Thanks for sharing that info on how you grow. Sounds like a really smooth process.

"At 8lb per gallon it was my best investment in DWC growing."
Amen to that! I still have the bilge pump that I planned on using when I started growing-hah!

 

[Ke0ncp]

Ok so that makes sense.

I am now thinking about one of These that are 57 gallons and put 2 plants in it. Or would it be better to run 2 of These at 27 gallons each and 1 for each plant. I will only grow 2 at a time.

I like the idea of the 1 large bin as then it’s only 1 monitor for PH and EC but then again as I type this I’m realizing that I need separate reservoirs so that I can react to each plants needs separately.

And yes that pump idea is great!

I’m feeling good about this and excited to experiment. My purple ghost candy needs to get on with it LOL. This is their current state

Edit:

Also how does everyone handle increasing nutes? Do you just raise the ppm to the desired level along with water levels during your weekly or whatever incremental top up?

 

[Delps8]

Ok so that makes sense.

I am now thinking about one of These that are 57 gallons and put 2 plants in it. Or would it be better to run 2 of These at 27 gallons each and 1 for each plant. I will only grow 2 at a time.

I like the idea of the 1 large bin as then it’s only 1 monitor for PH and EC but then again as I type this I’m realizing that I need separate reservoirs so that I can react to each plants needs separately.

And yes that pump idea is great!

I’m feeling good about this and excited to experiment. My purple ghost candy needs to get on with it LOL. This is their current state




Edit:

Also how does everyone handle increasing nutes? Do you just raise the ppm to the desired level along with water levels during your weekly or whatever incremental top up?

The CannaStats document I posted recommends 3 gallons per square foot of grow space. I have a "353 gallon" res that holds 28 gallons of nutes in my 2'x 4' tent. Due to how I train my plants, I grew just one plant for the past few grows but found that I wasn't filling the tent with one, highly trained plant so my next grow will be with two plants.

One downside to multiple plants in a res is that the roots intermingle and, if you need to harvest one plant or remove one plant, it could be a mess. I'll be putting a small milk craft, which will house my pump for the water chiller, between the two plants and will take pains to keep the roots separate.

A 27 gallon tote will hold 20 or 22 gallons, I'm guessing. That's a huge change from a 5 gallon bucket and are a lot of advantages, the biggest one being stability. Stability of pH and EC.

Going to a 57 gallon res is a different level again. I mix my nutes in a 32 gallon Brute trash can and end up doing 26 gallons per mixture. With a 330gph sump pump, it takes 5± mins to pump RO from the cistern into the Brute. If you go to a 57 gallon res, a 32 gallon mixing bin is too small - you'll need a 75 gallon bin to mix the nutes. That's a lot of floor space and a lot of water. It would be another step up in stability. Dunno. I've been fine with my 28 gallons of nutes for some very large plants. The 57 gallon tote (50 gallons of nutes) is about double that. I just don't know about working with that much water.

You'll definitely want to get away from pretty bottles. Jack's is dirty cheap - it costs me $1.18 to refill my res. I don't know what 26 gallons of nutes with Botanicare would cost but the simple fact is that when you get premixed nutes, you're paying for someone to mix the same 16-18 chemicals that come in a dry fert and then you're paying for that bottle to be shipped to your doorstep.

Re how to top up - I've posted a few papers on reservoir management and my approach is based on the recommendations in the CannaStats paper. I top up with RO and, when PPM has dropped to about 75% of starting PPM, I swap the res. In the Bugbee paper, he says that it's OK top off with ⅓ or ¼ strength Hoagland's solution but standard nute mix would be fine to use, as well. The difference between ⅓ and ¼ depends on the water use efficiency, IIRC, but I never got into that.

With the large amount of nutrient mix, I only do three res swaps. I foolishly tried a "bloom booster" in my most recent grow. It was a class A goat rope and it was only after I unf*cked that mess that I read the Fernandez posting (scienceinhydroponics) about why bloom boosters are unnecessary in hydro. If you read the excellent thread by @farside05, you'll get some valuable insights in nutrients. I run the same Jack's 3-2-1 mix from drop to chop and have zero issues.

Re. for details on how to grow in a 20-something gallon res, poke around in my grow journals. In the earliest ones, I was using bottled nutes and, perhaps it's a coincidence, I ran into nutrient issues de temps en temps. Once I switched to Jack's, things have smoothed out but I learned a lot about hydro growing along the way so it was coincidence, I'd have to say. I was using Botanicare before I switched to Jack's.

My most recent grow journal should have had a subtitle of "How to poison a cannabis plant" and the one before that was "How bud rot can ruin your day" so I have had my ups and downs. Overall, though, if you check out the first posting in my grow journals, you've got a pretty good equipment list and, if you read thought my postings, which weren't quite daily but were almost so, there's a lot of good info on what and what not to do.

 

[Ke0ncp]

The CannaStats document I posted recommends 3 gallons per square foot of grow space. I have a "353 gallon" res that holds 28 gallons of nutes in my 2'x 4' tent. Due to how I train my plants, I grew just one plant for the past few grows but found that I wasn't filling the tent with one, highly trained plant so my next grow will be with two plants.

One downside to multiple plants in a res is that the roots intermingle and, if you need to harvest one plant or remove one plant, it could be a mess. I'll be putting a small milk craft, which will house my pump for the water chiller, between the two plants and will take pains to keep the roots separate.

A 27 gallon tote will hold 20 or 22 gallons, I'm guessing. That's a huge change from a 5 gallon bucket and are a lot of advantages, the biggest one being stability. Stability of pH and EC.

Going to a 57 gallon res is a different level again. I mix my nutes in a 32 gallon Brute trash can and end up doing 26 gallons per mixture. With a 330gph sump pump, it takes 5± mins to pump RO from the cistern into the Brute. If you go to a 57 gallon res, a 32 gallon mixing bin is too small - you'll need a 75 gallon bin to mix the nutes. That's a lot of floor space and a lot of water. It would be another step up in stability. Dunno. I've been fine with my 28 gallons of nutes for some very large plants. The 57 gallon tote (50 gallons of nutes) is about double that. I just don't know about working with that much water.

You'll definitely want to get away from pretty bottles. Jack's is dirty cheap - it costs me $1.18 to refill my res. I don't know what 26 gallons of nutes with Botanicare would cost but the simple fact is that when you get premixed nutes, you're paying for someone to mix the same 16-18 chemicals that come in a dry fert and then you're paying for that bottle to be shipped to your doorstep.

Re how to top up - I've posted a few papers on reservoir management and my approach is based on the recommendations in the CannaStats paper. I top up with RO and, when PPM has dropped to about 75% of starting PPM, I swap the res. In the Bugbee paper, he says that it's OK top off with ⅓ or ¼ strength Hoagland's solution but standard nute mix would be fine to use, as well. The difference between ⅓ and ¼ depends on the water use efficiency, IIRC, but I never got into that.

With the large amount of nutrient mix, I only do three res swaps. I foolishly tried a "bloom booster" in my most recent grow. It was a class A goat rope and it was only after I unf*cked that mess that I read the Fernandez posting (scienceinhydroponics) about why bloom boosters are unnecessary in hydro. If you read the excellent thread by @farside05, you'll get some valuable insights in nutrients. I run the same Jack's 3-2-1 mix from drop to chop and have zero issues.

Re. for details on how to grow in a 20-something gallon res, poke around in my grow journals. In the earliest ones, I was using bottled nutes and, perhaps it's a coincidence, I ran into nutrient issues de temps en temps. Once I switched to Jack's, things have smoothed out but I learned a lot about hydro growing along the way so it was coincidence, I'd have to say. I was using Botanicare before I switched to Jack's.

My most recent grow journal should have had a subtitle of "How to poison a cannabis plant" and the one before that was "How bud rot can ruin your day" so I have had my ups and downs. Overall, though, if you check out the first posting in my grow journals, you've got a pretty good equipment list and, if you read thought my postings, which weren't quite daily but were almost so, there's a lot of good info on what and what not to do.

Ok yeah I need to read those PDF’s you posted before I ask anymore questions

The idea of the 1 big res is just not going to work for multiple reasons as you pointed out. I’m going to go with the smaller one and call it a day.

As for nutes they will be getting @Greenleaf Nutrients MegaCrop 1 part with a few other additions but nothing expensive or “pretty bottle” happening
Thanks for all of the information!

 

[Sativa1970]

With separate res per plant you have a quarantine. You know exactly how much each plant is eating and drinking. Huge insight into how the plant is growing and what it needs. Unless you are running clones at the same age and growth stage they will have different needs. One can be pulling K while the other is dumping N into the res showing a net 0 change in EC. If separated it is obvious on the meter what is happening with each plant.

Bigger res is always more stable. More water and nutrients at the plants disposal. More space to dilute the minerals that the plant doesn't want at that moment. Just like every thing else with growing there are diminishing returns. Increasing from 4 to 8 gallons may be twice as stable. Increasing from 50 to 100 gallons may be 2% more stable. You have to balance time, energy and wasted resources against the return.

The CannaStats document I posted recommends 3 gallons per square foot of grow space.

Defining the best anything for cannabis is a fools errand. There are too many strains and grow environments for one correct answer. If I am growing in a 2x2 and wanted maximum stability 12 gallon res would be a good guide. With this formula I should be using a 60 gal res. At 30 days my 20 gallon res just starts to get PH drift. The extra 40 gallons would just be wasted resources for my strains and grow conditions. It may be perfect formula for yours but you won't know until you try for yourself.

 

[Ke0ncp]

Ok so I picked up 2 of those 27 gallon bins. They will pretty much fill foot print of my 4x4 tent with just enough room for the heater, huey/dehuey.

Now to try and cut out an 8” hole on each of them without cracking the lids LOL.

I will leave that for a weekend project in a few weeks.

I am super excited to jump into this and I really appreciate all of the input and feedback

 

[Delps8]

With separate res per plant you have a quarantine. You know exactly how much each plant is eating and drinking. Huge insight into how the plant is growing and what it needs. Unless you are running clones at the same age and growth stage they will have different needs. One can be pulling K while the other is dumping N into the res showing a net 0 change in EC. If separated it is obvious on the meter what is happening with each plant.

Bigger res is always more stable. More water and nutrients at the plants disposal. More space to dilute the minerals that the plant doesn't want at that moment. Just like every thing else with growing there are diminishing returns. Increasing from 4 to 8 gallons may be twice as stable. Increasing from 50 to 100 gallons may be 2% more stable. You have to balance time, energy and wasted resources against the return.

Good explanation. Hand't thought about the quarantine angle.

Defining the best anything for cannabis is a fools errand. There are too many strains and grow environments for one correct answer. If I am growing in a 2x2 and wanted maximum stability 12 gallon res would be a good guide. With this formula I should be using a 60 gal res. At 30 days my 20 gallon res just starts to get PH drift. The extra 40 gallons would just be wasted resources for my strains and grow conditions. It may be perfect formula for yours but you won't know until you try for yourself.

I don't know if CannaStats defines 3 gallons sq/ft as being "the best". I wrote that they "recommend" 3 gals/sq foot. My res holds 28 gallons. It's a 2' x 4' tent so it's close to that value and it's worked out well for me.

I'm not sure how you ended up with 60 gallons for a 2' x 2' tent. That would be 15 gallons sq/ft and that's huge! "12 gallon res would be a good guide." - agreed and that's 3 gallons /sq ft.

 

[Zeefarmer]

Ok so I picked up 2 of those 27 gallon bins. They will pretty much fill foot print of my 4x4 tent with just enough room for the heater, huey/dehuey.

Now to try and cut out an 8” hole on each of them without cracking the lids LOL.

I will leave that for a weekend project in a few weeks.

I am super excited to jump into this and I really appreciate all of the input and feedback

3inch baskets work fine

 

[Ramblinrose1965]

3inch baskets work fine

I find cutting holes in totes is best accomplished by melting it as opposed to drilling.

I make a bunch of stuff out of totes for mushroom cultivation.

Find a 3lb can of tuna or the like. Cut both ends out, remove wrapper. Hold with pliers and hit with a torch till it's good and hot. Then just press it thru the plastic. Easypeasy and less chance of cracking than using a hole saw. Oh and do it outside it's stinky. If you have an old tote around practice first.

 

[Ke0ncp]

3inch baskets work fine

I’m going to use the lids from the mars hydro buckets I have. They have 6 inch pots so I figure 8” gives a little room for clearance

I find cutting holes in totes is best accomplished by melting it as opposed to drilling.

I make a bunch of stuff out of totes for mushroom cultivation.

Find a 3lb can of tuna or the like. Cut both ends out, remove wrapper. Hold with pliers and hit with a torch till it's good and hot. Then just press it thru the plastic. Easypeasy and less chance of cracking than using a hole saw. Oh and do it outside it's stinky. If you have an old tote around practice first.

Hey now! This is a great idea!! I can find a 8” diameter metal ring of some sort and do that I’m sure! Thanks for the idea there!

 

[Sativa1970]

I'm not sure how you ended up with 60 gallons for a 2' x 2' tent.

Sorry, I kind of rattled through the numbers so it wasn't clear. Formula is 3 galons x square foot. 2x2 area= 4 square feet. 4x3gal=12 gal res. My plants are 4.5 x 4.5 = 20.5 square feet each. 20 x 3= 60 gal res per plant. That's where the 60 came from. I use a 30 galon tote that holds 20 galons of water.

My comment on defining what's best was not meant as a dirrected attack at you. Sorry if it came off that way. It was meant in general for any advice including my own. Your plant, in your grow, is the only one that knows what the right answers are. It's like me asking advice on growing my peach treas in the midwest and getting advice from a south American banana farmer. They are both fruit trees after all.

They have 6 inch pots so I figure 8” gives a little room for clearance

The roots are going to grow out the sides and bottom of the net pot. 8 inches is going to be tight or impossible to lift out. If you are not transferring, the only time you need to lift is after harvest. You can cut away roots to get it out then.

 

[Ke0ncp]

The roots are going to grow out the sides and bottom of the net pot. 8 inches is going to be tight or impossible to lift out. If you are not transferring, the only time you need to lift is after harvest. You can cut away roots to get it out then.

Ohh that’s right, I think you had mention 10” hole

 

[Ke0ncp]

I found this on the Zon that looks interesting.

OK SO update on this. I purchased it and just did a quick read through of the manual and I am really impressed, it doesn't take much

You can fully "control" it via an app. You can calibrate it, set high/low alarms for water temp, ph, ecc and ppm and view all of them from anywhere once you get it set up to wifi!

This means I dont even have to stick my head in the tent to know what is going on with my reservoir!!

Now time will only tell if it is all its hyped up to be, but for now I am pretty excited about this! Time to get another one so that I can keep track of both reservoir's

 

[Delps8]

OK SO update on this. I purchased it and just did a quick read through of the manual and I am really impressed, it doesn't take much

You can fully "control" it via an app. You can calibrate it, set high/low alarms for water temp, ph, ecc and ppm and view all of them from anywhere once you get it set up to wifi!

This means I dont even have to stick my head in the tent to know what is going on with my reservoir!!

Now time will only tell if it is all its hyped up to be, but for now I am pretty excited about this! Time to get another one so that I can keep track of both reservoir's

Wow, that's a good find!

You'll love it. I have a Bluelab monitor that I bought in 2017 so it's not WiFi and I have to use a web cam to check it. At 20-something gallons, things don't change very quickly, though (that's a feature, not a bug).

Oh, I record PPM and use PPM in my grow journal here. I realize that EC is the standard but, with a big res, it may take a long time (a few days) for EC to change 0.1 units. If you're tracking by PPM, you'll see 500, 510, 520, etc vs if you're tracking using EC, in tenths of a unit, it will only read 1 until PPM reaches 526 and then it will flip to 1.1. Since PPM is expressed in multiple scales, I use the syntax "xxx/500" to denote the 500 scale.

And then we learn that PPM really doesn't mean much of anything… ;-)