Reservoir & Drip Irrigation System

[Drivejunky95]

My theory with a drip irrigation system (besides convenience) is water and nutrients are more readily flowing through your medium.

What my hope is, if I do build a drip system, the more consistent water flow will produce more runoff more often, and in turn prevent CEC nutrient/salt buildup and increasing pH levels (with no waste water!)

I think the benefit of a looping and exposed reservoir is you can more easily and readily monitor pH. I think the looping system will bring the reservoir and the medium into a (relatively) close pH equilibrium over time.

My only concern with this setup is pH drift - from nutrient water in reservoir 'aging' - if the nutrient water does indeed drift with age.

Can anyone attest to this? Fact or fiction? Thanks.

 

[Old Salt]

After three days my pH has gone up 0.07 from 6.24 ± 0.04 in three days. This is in a non-aerated drain to waste coco/perlite system, using General Hydroponics' Flora Trio and supplements in the Bloom and Ripen stage.

The keys here are non-aerated, and drain to waste. An aerated, recirculating system may be different.

 

[Drivejunky95]

It's good to hear pH drift is not an issue with nutrient water over time.

But yikes, perhaps some research is required for an adequate air stone depending on the reservoir size.

Insight is very much appreciated!

 

[Old Salt]

When I designed my built. but never used RDWC system, I had air stones in each of the four pots as well as in the reservoir. I bought the Hydrofarm AAPA45L 20-Watt 45-LPM Active Aqua Commercial Air Pump for use with this system. As I said, this is an unproven design.

Your pH may be an issue. I've read that aeration affects the pH, as does recycling the nutrient solution.

 

[Drivejunky95]

Hey you grow in coco too, yea?

Did you run into this with your system too? Runoff pH started going up (6.5-6.6) after oh, about a week (5.8-6.3 going in).

Got myself an RO system as a recommendation from a member here (@fanleaf many thanks, man, it's working great!) and pH is way easier to manage now.

I think once nutrient water enters the (coco) medium it will start rising in pH a little again (hand watering) so I think a drip system will help regulate (CEC) pH with more frequent and more runoff waterings - if that's how it indeed works.

But if recirculating/looping and air stones cause pH issues that's really a bad sign.

 

[Old Salt]

Hey you grow in coco too, yea?

Did you run into this with your system too? Runoff pH started going up (6.5-6.6) after oh, about a week (5.8-6.3 going in).

Got myself an RO system as a recommendation from a member here (@fanleaf many thanks, man, it's working great!) and pH is way easier to manage now.

I think once nutrient water enters the (coco) medium it will start rising in pH a little again (hand watering) so I think a drip system will help regulate (CEC) pH with more frequent and more runoff waterings - if that's how it indeed works.

But if recirculating/looping and air stones cause pH issues that's really a bad sign.

Yes, I grow in coco/perlite. I water once per day during the seedling stage, then twice per day until harvest. I start with a shot glass, and end up with automatic watering about two cups per watering from the aggressive vegetation stage until harvest. Every watering is to run off.

I don't aerate my reservoir. I only check and adjust pH whenever I mix a new batch of nutrients. I've only checked the TDS of my nutrient solution once, to help out another member. My thoughts are the PPM will be where it needs to be for the concentration of nutrients I'm using. Prior to today, I've only used my TDS meter to check my RO on a monthly basis. I'm either right, lucky, or lazy. Take your pick.

 

[Drivejunky95]

I hear ya, man!

The nute schedule I found online (cocoforcannabis) recommended ~1100 EC for my plants during late veg and it wasn't until I started noticing leaf curl and drooping that I checked runoff EC - and it was 2000!

It just goes to show the plants can take up to 2000 EC before showing signs of struggle - no where near 1100 EC! There's no exact science in organic experimentation, but that's the beauty of it.

 

[Old Salt]

I hear ya, man!

The nute schedule I found online (cocoforcannabis) recommended ~1100 EC for my plants during late veg and it wasn't until I started noticing leaf curl and drooping that I checked runoff EC - and it was 2000!

It just goes to show the plants can take up to 2000 EC before showing signs of struggle - no where near 1100 EC! There's no exact science in organic experimentation, but that's the beauty of it.

EC is the conductivity. It is due to the dissolved solids in whatever you are checking. As your solution passes through the coco, it will pick up more. That's where the high EC comes from. As long as I get 10% or more run off, I don't worry about it.
You just got an RO. Many of them have a "re-mineralization filter" as their final stage. This is filled with coco, and is used to give the water some taste. The water goes into this stage with a very low EC, and comes out with a much higher EC. Mine is 29 in, and 92 out. I wouldn't worry about it if you are getting the proper run off. Too many growers tend to overthink what they are doing.

The best advise I can give is to pick a low starting point, and let the plants tell you what they need. I started at 25% of the label concentrations without any problems. I moved up to 30% for my next grow, and went up to 40% for my current grow. I backed off to 30% as I was seeing signs of nutrient burn. Those signs disappeared from new growth in less than four days.

Did you follow the link for my automatic waterer above? There was a mistake in the manual for the timer. The interval time on + time off should equal the on time for the times of day it is active.

 

[Drivejunky95]

Thought it was a forum auto link but looking at it now! A 5 gal bucket for a reservoir is a sweet spot - have got tons laying around needing some kind of re-purposing, hate to see them going to waste.

Seeing what you're getting at with an automatic timer - it could come on when the lights come on and water for a bit, word is plants like water when the sun comes up, but that could be an old wife's tale

Water would happen again ~10hrs later, same amount, to runoff.

Thanks for putting up with me/this, I see your motor, I should get one as well on ebay or amazon, it be an adequate LPM or GPM. The motor in the thread is your Hydrofarm AAPA45L 20-Watt 45-LPM Active Aqua Commercial Air Pump? IIRC I saw your thread a few weeks back you had 4 plants growing in coco!

 

[Old Salt]

No, that's not the air pump. That's a self-priming water pump I use to water the plants. I water twenty minutes after the lights come on, and 100 min before they go off.

The pumps are available from eBay for less than $5.00 CDN. There are links for the pump and step down converter a few posts later in the thread. The step-down converter is used to slow the pump output to a little over a liter per minute. Between the slowed down pump, and ability to set on-time in seconds at the timer I can specify the amount of water down to the teaspoon per plant.

I'm not using the Hydrofarm AAPA45L 20-Watt 45-LPM Active Aqua Commercial Air Pump, since there's no aeration in my system. I had to switch from RDWC when I found my well would not provide enough water to support that method. Drain to waste uses about 1/3 the water required for RDWC.

 

[Drivejunky95]

Alright, so use a step down converter to lower the water pump volts(?) to decrease pump rotations and output water and this creates an ideal water flow for system. Don't not believe you if you can calculate the water entering the plants. That's the kinda precision for analyzing the results for a grow (30% nutes to 40% and back to 30%, and perhaps a few % more and more with time).

I need to ask you (I mean no offense in asking) why do this? In my head there must be water pumps that can output a water flow that doesn't overwater plants or outputs more water than necessary? But perhaps these pumps designed for gardens with larger output?

I had to google. RDWC = Recirculating Deep Water Culture. An isolated (looping) system would recirculate the water, that does not lose water. Drain to waste would waste lots of water.......... 1/3 less, how is that possible?

 

[Old Salt]

Alright, so use a step down converter to lower the water pump volts(?) to decrease pump rotations and output water and this creates an ideal water flow for system. Don't not believe you if you can calculate the water entering the plants. That's the kinda precision for analyzing the results for a grow (30% nutes to 40% and back to 30%, and perhaps a few % more and more with time).

Yes, the step-down converter drops the voltage to the pump, which slows it down. I based the amount of nutrient solution I wanted to send to the plants to be the same as I was hand watering them to start. Now I measure the run off in the drain trays, and adjust the length of time the pump is on to change that. From 18l of nutrient solution I want about 1-1/2 liters of run off.

Watering by hand, I used a measuring cup, and poured the water near the stem of the plant. It took five to ten seconds to pour it in that one spot. Now I have 16 holes located about half way between the stem and edge of the pot. The water is distributed more evenly through the coco. I wanted a slower feed for two reasons. First to allow the water to soak more evenly through the coco, and second to avoid waste by having a finer control over the amount fed to each plant.

I need to ask you (I mean no offense in asking) why do this? In my head there must be water pumps that can output a water flow that doesn't overwater plants or outputs more water than necessary? But perhaps these pumps designed for gardens with larger output?

This is what I had on hand. There are automatic watering systems available through Amazon and eBay. I didn't think much of them. My way is much more accurate, and flexible. Like I said, I had that pump on hand. I could have used a peristatic or dosing pump, or a gear pump as well.

I had to google. RDWC = Recirculating Deep Water Culture. An isolated (looping) system would recirculate the water, that does not lose water. Drain to waste would waste lots of water.......... 1/3 less, how is that possible?

The four plant RDWC I designed needed 2-1/2 gallons in each pail, and another five in the reservoir. Over the period of a week, I would need to add another four or more gallons to maintain the TDS. That's 19 gallons per week as a minimum. I'm feeding roughly one quart per plant per day. That's a gallon a day, or seven gallons per week. 7/19 = .368 or 36.8%

 

[Drivejunky95]

Believe I understand. In a RDWC reservoir, in order to maintain the TDS, new, larger amounts of nute water are required to be added... because the volume of water proves more difficult to raise and maintain TDS.

In a drain to waste, you control fresh nutes as needed per TDS, and therefore it requires less water. It is in and out in this system. Do I follow you correctly?

 

[Old Salt]

In any hydroponics system where the whole nutrient mixture is in constant use (DWC, RDWC, ebb & flow, aeroponics) pure water is added to replace that lost to evaporation. Evaporation is very high due to the constant aeration required. This tends to concentrate the nutrient solution, increasing the TDS. The plants draw nutrients from the entire nutrient solution affecting both the TDS and pH of the entire solution. This means both the TDS, and pH of the nutrient solutions must be monitored, and adjusted as needed.

In drain to waste systems, the plants do not have access to the entire nutrient solution, only that part which is fed to them. There is no aeration, at least in my implementation, so evaporation of the nutrient solution is close to none. This means the TDS and pH of the nutrient solution remains relatively stable. No monitoring or adjustment is required after a batch of nutrients has been mixed.

 

[BAKIND]

Your pH may be an issue. I've read that aeration affects the pH, as does recycling the nutrient solution.

I have noticed that aeration does indeed affect the ph. In my case it tends to raise ph.

 

[BAKIND]

I hear ya, man!

The nute schedule I found online (cocoforcannabis) recommended ~1100 EC for my plants during late veg and it wasn't until I started noticing leaf curl and drooping that I checked runoff EC - and it was 2000!

It just goes to show the plants can take up to 2000 EC before showing signs of struggle - no where near 1100 EC! There's no exact science in organic experimentation, but that's the beauty of it.

keep in mind that the actual EC that is available to your plants ( in the medium ) is not the inflow EC of your feed. It's closer to your runoff EC.

That's why i feed frequently and thouroughly, and I monitor my run off EC closely. Today, I am feeding them a slightly lower EC, to keep the run off EC from running away sort of speak.

 

[Drivejunky95]

In any hydroponics system where the whole nutrient mixture is in constant use (DWC, RDWC, ebb & flow, aeroponics) pure water is added to replace that lost to evaporation. Evaporation is very high due to the constant aeration required. This tends to concentrate the nutrient solution, increasing the TDS. The plants draw nutrients from the entire nutrient solution affecting both the TDS and pH of the entire solution. This means both the TDS, and pH of the nutrient solutions must be monitored, and adjusted as needed.

In drain to waste systems, the plants do not have access to the entire nutrient solution, only that part which is fed to them. There is no aeration, at least in my implementation, so evaporation of the nutrient solution is close to none. This means the TDS and pH of the nutrient solution remains relatively stable. No monitoring or adjustment is required after a batch of nutrients has been mixed.

I gotchya now. Didn't even think to consider evaporation causing water loss. That makes a lot of sense.

So the step down converter used to slow the pump let's the water be more evenly and slowly distributed in the coco via x16 holes (spikes?).

That's a good setup because it doesnt leave lots of room for dry spots that let salts build up.

That sounds like the issue in coco, at least it could be why runoff pH increases and the ppm/EC went up so high (when I put 1100 EC nute water in and after about 1 week it started coming out at 2000 EC). And again, 5.8-6.3 pH going in, 6.5-6.6 pH coming out.

Do you think these issues are unavoidable in any setup? Basically I'd love designing a system that keeps ppms and pH nice and even for as long as possible without needing to flush 1x a week or so.

I think there's a misconception that pH of water going in is enough to keep the medium's pH in a range that allows different nutrients to be taken up by the plants. Good water pH helps but I think it's ultimately the medium's pH that determines how well a plant will do. Something is causing build up, and I'm thinking it's frequency and even distributions of waterings that keep the coco ph and ppms in check.

 

[Old Salt]

So the step down converter used to slow the pump let's the water be more evenly and slowly distributed in the coco via x16 holes (spikes?).

They are holes I drilled in the hose and fittings with a #78 bit. Slower is the key.

That sounds like the issue in coco, at least it could be why runoff pH increases and the ppm/EC went up so high (when I put 1100 EC nute water in and after about 1 week it started coming out at 2000 EC). And again, 5.8-6.3 pH going in, 6.5-6.6 pH coming out.

I don't worry about, or even measure the TDS (EC) in the run off. The only time I check the pH is when I prepare the coco for its first use. I flush the new coco with pH 5.8 water with CALiMAGic in it until the run off is between 5.8 and 6.2. Any time water is in contact with plant material such as coco, it will change its pH, and TDS. If you take some coco and flush it until the run off is pH 6.0, then leave it overnight, and pour the same water into the coco, you'll see this.

 

[Drivejunky95]

They are holes I drilled in the hose and fittings with a #78 bit. Slower is the key.


I don't worry about, or even measure the TDS (EC) in the run off. The only time I check the pH is when I prepare the coco for its first use. I flush the new coco with pH 5.8 water with CALiMAGic in it until the run off is between 5.8 and 6.2. Any time water is in contact with plant material such as coco, it will change its pH, and TDS. If you take some coco and flush it until the run off is pH 6.0, then leave it overnight, and pour the same water into the coco, you'll see this.

I thank you for your time and insight.

I'll pass this knowledge forward here on the forum!

 

[Drivejunky95]

Yes, I grow in coco/perlite. I water once per day during the seedling stage, then twice per day until harvest. I start with a shot glass, and end up with automatic watering about two cups per watering from the aggressive vegetation stage until harvest. Every watering is to run off.

I don't aerate my reservoir. I only check and adjust pH whenever I mix a new batch of nutrients. I've only checked the TDS of my nutrient solution once, to help out another member. My thoughts are the PPM will be where it needs to be for the concentration of nutrients I'm using. Prior to today, I've only used my TDS meter to check my RO on a monthly basis. I'm either right, lucky, or lazy. Take your pick.

Yooo @Old Salt

Question for ya.

Do you know your GPH or LPH of your water pump after using the step down converter?

Seeing some 80GPH ones online, just dont wanna blow the 1/2 plug out the end of the system if I dont use a water regulator after turning it on lol!