New reservoir size

[Rodrigo]

Hi, everyone.

I'm upgrading my systems and one of the new improvements is the container I use for a reservoir. I grow hydro in an E&F system for my flowering room and a drip for my veg. So, to the issue.

The container I'm currently using (for flower) holds about 20lt (little less than 5gl) of nutrient solution and I'm thinking about switching to a container that holds about 70lt (18gl), but I don't really need that much water to fill the flood tables and hoses and such (complete the circle, sort of speak). I still have to run a system test in order to know exactly how much water I'll need but I can't do that now since I'm waiting for some supplies to arrive.

But my questions is, regardless of the amount of water I need circulating in the system, is it better to have a bigger res? i.e. As a rough estimate I calculate that I'll be needing about 5-8gl of water to fill the containers and hoses and the rest of the water sits in the res covering the pump. I have the option of getting a smaller container which will hold about half as much water but still should suit my needs (fill the system and still have enough in the res to cover the pump).

So far, I'm changing the water in the res and adding fresh nutes (Organic Iguana Juice, from AN) once a week, so obviously if I use 3-4 times the amount of water I'll need 3-4 times the amount of nutes. So I was thinking in adjusting the quantities to allow me to change the water every two week and still use the same or just a little more nutes.

So to summarize, is it better to have a big res with a lot of water to spare and change it every two weeks or is it the same as having a res with just the right amount of water to keep the system going and change it every week? (if not enough water, the pump won't have water to pump)
I have enough air pumping into the res, just in case someone was wondering.

Hopefully someone will be able to answer. I'm sorry if it's not clear, feel free to ask any question if it helps clarify my intentions.

Thanks, guys!

 

[Rodrigo]

Come on, guys, someone has to know if having a big res is the same or better than having a smaller one. It's by far one of the simplest questions around.

 

[GreatLife4All]

Let me give this a try then...

Reservoir size is definitely a trade-off... very similar to pot size in soil.

The only advantage that I can see to making the reservoir as small as possible is a cost savings. You can use the minimum amount of nutrients and save a little money. The problem, though, is that a small reservoir needs to be changed much more frequently.

But there are many advantages that come with larger reservoir size. Probably the greatest advantage comes from the more stable environment. Because you have more water and nutes, the plants won't affect the solution as much. Therefore, the pH will remain more stable... the PPMs will remain more stable. You can also go longer between nutrient changes - thus saving money.

I have a spreadsheet which shows that for a 16 week grow using a 25 gallon reservoir, changed weekly - that the cost of nutrients is $270 (Advanced Nutrients). In actuality, I use a method of filling my system, and then I fill a reservoir with the same amount. When the reservoir is out - it is time to change out and clean the system. During veg and bloom - this can be 5 weeks. When you get to the end, it lasts about 2.5 weeks. So my actual nutrient cost is a lot less than the projected costs in the spreadsheet for changing every week.

If you want to compare apples to apples... then we would need to compare a 25 gallon system to the 5 gallon equivalent - and it would look like a 5 to one advantage. But the ability to change the 25 gallon system every 2 to 3 weeks already cuts that advantage significantly. The better growth is very hard to quantify though...

So by using a larger reservoir and a different plan, I am using about the same amount of nutes. But, my pH is more stable; my PPMs are more stable; plant growth seems a lot better and easier to control. There is no way I would go back to a 5 gallon bucket...

 

[Rodrigo]

Thanks!
Ok, so I'm sold on the bigger res, however I failed to understand the system you implemented, which is ok because I don't have that much space available to I can't really put a second res in there, but I'd still like to understand what you did.

I use AN Iguana Juice for both veg and flower and the cost is really low, so far.
I started (for veg) a one liter bottle ($60) the last week of December and I still have about a third left (I'm 2 weeks away from my third harvest since), I change the res weekly but it is very small, I use a 10 liter res for veg since the girls are on a drip so very little water circulates through the system when the pump in on, I'll probably switch to a bigger res since this week I'm finishing the upgrades to the veg to accommodate more plants (only 6, though) and I'll probably need more water to fill the system.

For the flowering room I started the one liter bottle (also $60) the first week of February and I run out 3 days ago with the last weekly water change (but if I go to the math of it I should have run out about 10 weeks ago, so might have been using less than the required amount), so roughly 5 months and 3 harvests with $60, I think that's very acceptable (flower times are 8-9 weeks) and I'd like to keep it very close to that, so by using say 60 liters of water in the res I use roughly 180 ml of nutrients per water change, this allows for about 5.5 changes before I run out again, so if I could manage to change the res every 3 weeks (4 would be better) the I can keep the costs down, do you think this can be done? with the current setup I have to put more water in the res about 3-4 days after the change (just plain water, no more nutes) so if I go with the 60 liter I'd probably have to put more water in there in about 10 days after changing it.
I have a small air compressor putting 20 lt/min (315 gl/hr) of air through air stones in the res, this should be enough O2 in the res, I think? it runs 24/7

Does it make sense that if I use 3 times more water then I can go 3 times longer without changing the water and just topping off?? does it work this way? is there a rule as to when you should change the water?
I was told that if you pump enough air in there then you can just top off with more water and nutes but there's no real need of changing the water completely, I disagree but I'd like to get someone's opinion.

Thanks again!

 

[GreatLife4All]

Sorry, let me see if I can explain it a little bit better.

Let me start at the house water and explain from there...

Well->Iron Filter->Water Softener->R/O Filter System

Everything up to this point is to clean up my rather dirty (from a ppm and salt perspective) well water. It comes out at about 30 to 40 ppm right now, and gets as high as 125 during the winter.

R/O Filter System->Water Storage Tank->Pump->Nutrient Refill Tank->Gravity Feed->Float Valve->RDWC System

This is is the part of the system related to my growing environment.

The first stop for water is the Water Storage Tank. This is a 66 gallon storage tank for pure R/O water. I maintain it by adding 10ml/liter of H2O2 weekly. It stays very clean. PPM and pH are very stable. Water from this tank is hooked up to an electric pump - which is connected to two storage tanks (one for each hydro system) that I call Nutrient Refill Tanks. These are the tanks which hold pre-mixed nutrient solution which is then added to the RDWC system upon demand. The Nutrient Refill Tanks are stored above the level of the fluid in the RDWC system - and this allows them to gravity feed into the RDWC System via a float valve. I use the float valve to set the level of the nutrient solution in the RDWC system.

The Nutrient Refill Tanks are 30 gallons. My RDWC system holds anywhere from 15 to 36 gallons - depending on where I am holding the level of the float valve. So I can completely fill the RDWC system from the Nutrient Refill Tanks. And I can fill the Nutrient Refill Tanks twice from the Water Storage Tank.

Maintenance in my system consists of first filling the Nutrient Refill Tanks with pure water. I then mix whatever Nutrient Solution I want in my RDWC system. The next step is to drain and clean the RDWC system completely. Cleaning depends on where the plants are and whether or not I am using SCROG, etc - I do the best I can. After cleaning, I then fill the RDWC system from the Nutrient Refill Tank. I then fill the Nutrient Refill Tank with water and mix in a different version of the Nutrient Solution - which I call my Refill Solution.

As the water level drops in the RDWC system, the float valve drops. When the float valve drops, Refill Solution from the Nutrient Refill Tanks is added to the RDWC until the level rises again. So as the plants use the nutrient solution - Refill Solution is immediately added back into the system; thus maintaining a constant level in my RDWC system.

Nutrient Solution and Refill Soution are slightly different. My Nutrient Solution is exactly (or as near as I can get) at my target for this stage of growth. My Refill Solution has been diluted to 75% strength - and I don't add any bacteria or fungus (Root Zone, Tarantula, Sensizyme, etc). I set the pH about .3 lower than target. This difference allows the Nutrient Solution to stay relatively constant (at target) on pH and PPMs.

I never mix nutrients in my RDWC system - I add pre-mixed nutrient solution that I know has the correct PPMs and pH after mixing in the Nutrient Refill Tanks. This helps to eliminate accidental burning mistakes from incorrectly mixed nutes. The only exception to this rule are the additives that contain bacteria, fungus, and enzymes. I add them directly to the RDWC system and never into the Nutrient Refill Tank.

I have posted information in another thread on how to maintain an RDWC system, I will see if I can find it. But if you have and know how to use a pH meter and a TDS/EC/PPM meter then you can extend the life of the nutrient solution significantly. The key is to find a way to keep the ppms, pH, and nutrient levels relatively constant (or at least within bounds that won't effect the growth of the plant in a negative way).

Hope this was a better explanation.

 

[GreatLife4All]

Here is the other post that I referenced:

This depends on your experience... As a beginner, you should run at least one grow where you drain and clean your reservoir every week. You then refill with new nutrient solution. If you run low of solution during the week, simply top off with pH corrected water. This is very simple, it works well, and is the way that you should introduce yourself to DWC or hydro. If you are careful with mixing nutrients, you only really need a pH meter to succeed using this method.

In order to run more than a week, you need experience with diseases, nutes and plants. The problem is that the plants consume most of the "mobile" elements within a day or two. A second problem is that the longer you run between cleaning - the higher the likelihood of disease. The third issue is nutrient imbalance... too much of a good thing can be bad. After you have run a couple of grows changing weekly and know how the plants grow, you can then try and top off with nutrient solution (Good starting point - dilute to 75% of normal strength and adjust pH .2 below desired level) rather than ph corrected water. Doing this and watching both your PPMs and pH on a daily basis will allow changing the water every two weeks. If done correctly, you will get better growth from your plants using this system.

I have done every possible routine in changing nutrients. Really, I have.

Over the past six months I have built a system of reservoirs and floats that allow everything to automatically adjust based on metrics that i have gathered. I now only change my water 3 times during flowering... at the end of transition... at the end of bloom... and at the end of aggressive bloom. But I also have a reservoir attached to a float... know how to set the ppms so that it stays constant over a long period of time... and I know enough about pH that I can keep it constant using the pH of my refill solution. I also know and understand diseases - i used "dirty" water to fill my system and suffered thru my first instance of root rot, It was very educational - I nearly threw away the plants... but ended up with a huge yield. Very proud of myself on that one to be honest. I now use amendments (Food grade 35% H2O2 and Dutch Master Root Zone) that lower the risk of the root rot resurfacing. But H2O2 is dangerous to use with live plants and a thriving bacterial colony... you must be careful to avoid damage.

So my solution can run for greater than a month with no changes and without any damage to plants.

 

[Rodrigo]

That was very educational and I understood your system, sounds like you got it all figured out!

Well like I said before, due to lack of space I can't really have a Nutrient Refill Tank, just the main tank for the E&F system.

To be honest, I don't know anything about PPM or how to regulate them. I don't use RO water because the equipment is too expensive for my budget so I just use plain tap water. Where I live water is rich in chlorine, calcium and potassium (I think, never really tested for these elements, it's just what I know about the water in my city. The chlorine is a given, you can almost taste it. This makes it drinkable and safe for everyone, for cooking or washing vegetables and fruits)
I'm on my third grow so far and every plant I've kept so far has yielded about 40g each (dry, with no stems or leaves), and due to space restrictions (3 in a 24"x24"x50" space) they only grew to be about 26" tall, maybe a little more)

I grow organic so it's been hard to find a suitable PH regulator. On the last grow I used H3PO4 to lower the PH (tap water comes out @ 7.1) but after about 2 days the PH went back up, and the leaves started to turn yellow (really bright) from the tips inwards, it reached about half way into the leaves before harvest. Although I'm not sure if it was the H3PO4 that caused the issue because about a week before starting the flower cycle I had a problem with the water timer and the girls were fed for about 13-14 hours. Either way, I changed the timer, stopped using the H3PO4 and now everything is back to normal.
I haven't had a single problem in the past 8 months (except from the above), no deficiencies, bugs, rot, burn, diseases etc. It has been an almost perfect experience and I'm very happy with the yields I've been getting and the potency and overall quality is amazing.

The only 'concern' that I have at the moment is that the root of the plants in flower look a little orange/brown (can't tell exactly because I'm a bit colorblind, but definitely not white) so naturally I thought root rot, but other than the slightly colored root there's no problem, they don't smell at all and as far I've read when you have root rot they smell rotten or strong, mine don't have any smell whatsoever, so I'm thinking that the nutes may be coloring the roots or the exposure to light, now they are in a clear plastic container so you can see the roots from the sides, but this is going to change after harvest because of the upgrades I'm making, they're now going into window boxes (I think that's what they're called, think long rectangular pots). I have only two more weeks til harvest so not a major issue right now.

Ok, so back to the water; given that I don't have a way of regulating the PH at the moment I don't even bother checking it anymore, I've never checked the PPM as I don't have a reader and they are expensive here, I was going to order one online but it'll take about a month to arrive, and since I've had no visible problem then I assume everything is a good as it can given the conditions.

Would I get better yields and quality if I improve upon a few things? probably, but I can't justify the extra expenses at the moment, after all the reason I grow only a few plants at a time is because I grow for me, not for commercial use as it is very illegal here and I'm not a dealer and the prices for illegally acquired weed of A LOT less quality (not even with a strain name, with sticks, leaf matter, and sometimes seeds) range from $450 to $670 an ounce.

I drain and clean the system every week, including the container, pump, and as much as I can of the tubing and air stones, refill straight from the garden hose and add nutes (Advanced Nutrients Iguana Juice Bloom) Water temps are about 15°C now that's winter, in summer they can up to about 24°C, ambient temps stay between 17° and 20°C whether lights are ON or OFF.

I don't know if I can add anything else but you're welcome to ask. So given the information above, what kind of problem can you foresee if I switch to a bigger water res, considering that I'll now grow 6 plants (perhaps 9 in a couple of cycles) instead of the three I've been growing so far.

Ok, that was a lot longer than I was expecting (that's what she said) so thank you for taking the time to both read and reply.

 

[GreatLife4All]

To be honest, I don't know anything about PPM or how to regulate them. I don't use RO water because the equipment is too expensive for my budget so I just use plain tap water. Where I live water is rich in chlorine, calcium and potassium (I think, never really tested for these elements, it's just what I know about the water in my city. The chlorine is a given, you can almost taste it. This makes it drinkable and safe for everyone, for cooking or washing vegetables and fruits)

All of this works just fine. I started my grows using tap water from the city. it is very important to let it set for 24 hours before use - this will let the chlorine settle out. Other than that, the only advantage to R/O water over tap is that it is a lot cleaner.

PPM is simply parts per million. It is used to measure the concentration of nutrients in your nutrient solution. For growing in soil, if you follow label directions you will be fine... No need to understand them. But it is a relatively easy concept.

Assume that you have some quantity of water - and that it contains exactly 1 million molecules of water. When you add your fertilizer solution to this water in the correct amounts, you end up with something like 150 of those 1 million parts now being nitrogen. Just to continue the example, another 100 of those could be phosphorus; another 200 could be potassium. So now you have a million molecules of nutrient solution (ignore the fact that we would have more in real life) - and it now has 999,550 molecules of water and 450 molecules of N,P, and K. The nutrient solution is now said to have a PPM of 450.

You measure PPM in a rather straightforward fashion. Each molecule of nutrients carries an electrical charge. A PPM meter simply measures this electrical charge and converts that into a PPM reading. Because it uses a disturbance in an electrical charge to determine the PPM - the measurement of the electrical charge is called EC. Unfortunately there are two different conversion factors between PPM and EC - one uses a constant value of .7 and the other uses a constant value of .5. So the same EC (let's assume a value of 1,000) can produce a PPM value of either 500 or 700 - depending on the meter.

And finally - because you are measuring what are known as "dissolved solids' in the water - sometimes these meters are referred to as a TDS Meter.

An EC meter for soil works in the same way - but uses different equipment to measure the total dissolved solids available in the soil.

I'm on my third grow so far and every plant I've kept so far has yielded about 40g each (dry, with no stems or leaves), and due to space restrictions (3 in a 24"x24"x50" space) they only grew to be about 26" tall, maybe a little more)

Seriously - 40g average is pretty damn good for soil.

I grow organic so it's been hard to find a suitable PH regulator. On the last grow I used H3PO4 to lower the PH (tap water comes out @ 7.1) but after about 2 days the PH went back up, and the leaves started to turn yellow (really bright) from the tips inwards, it reached about half way into the leaves before harvest. Although I'm not sure if it was the H3PO4 that caused the issue because about a week before starting the flower cycle I had a problem with the water timer and the girls were fed for about 13-14 hours. Either way, I changed the timer, stopped using the H3PO4 and now everything is back to normal.

I saw you make a comment about this on a different thread a while back. I meant to comment but life took over... I would be very skeptical about H3P04 hurting your plants - unless you used way too much of it. I am going to assume that you diluted it in water - and didn't just pour it straight on your soil.

When H3PO4 breaks down in water (soil contains water and it breaks down the same way) - you get 3 H+ ions, an O2 molecule (which is Oxygen in it's normal state, and a P2O4 molecule. P2O4 is the form of phosphorus that the plant takes up - so you have added a small amount of P. The O2 molecule eventually escapes to the atmosphere or is absorbed by the plant root system. It is the free H+ ions that cause the pH to decrease.

In it's simplest form - pH can be considered a measurement of the amount of H+ ions that are in a liquid. An acid solution has an excess of H+ ions (it wants to get rid of them); an alkaline solution has a deficit of H+ ions (if any become available - parts of the solution will bind to them and take them out of circulation. Water is at pH of 7 when it neither needs more H+ ions or has an excess of them.

All this to explain - when you use H3P04 correctly - you are adding oxygen to the water (good); you are adding P to the water in a plant available form (should be good as it is a small quantity); and you are adding H+ ions - which causes the pH to go down (which was your original target).

I just don't see any way that H3PO4 is harmful to a plant when used correctly.

I haven't had a single problem in the past 8 months (except from the above), no deficiencies, bugs, rot, burn, diseases etc. It has been an almost perfect experience and I'm very happy with the yields I've been getting and the potency and overall quality is amazing.

Glad to hear that it is going well for you.

The only 'concern' that I have at the moment is that the root of the plants in flower look a little orange/brown (can't tell exactly because I'm a bit colorblind, but definitely not white) so naturally I thought root rot, but other than the slightly colored root there's no problem, they don't smell at all and as far I've read when you have root rot they smell rotten or strong, mine don't have any smell whatsoever, so I'm thinking that the nutes may be coloring the roots or the exposure to light, now they are in a clear plastic container so you can see the roots from the sides, but this is going to change after harvest because of the upgrades I'm making, they're now going into window boxes (I think that's what they're called, think long rectangular pots). I have only two more weeks til harvest so not a major issue right now.

The nutes are definitely coloring the roots - it happens with a lot of different nutrient formulations.

The smell of root rot is very distinctive and you will know if and when it happens...

I don't know if I can add anything else but you're welcome to ask. So given the information above, what kind of problem can you foresee if I switch to a bigger water res, considering that I'll now grow 6 plants (perhaps 9 in a couple of cycles) instead of the three I've been growing so far.

Ok, that was a lot longer than I was expecting (that's what she said) so thank you for taking the time to both read and reply.

I believe that you have everything under control my friend. Sounds like you have learned a lot in a very short period of time.

And I totally agree that home grown weed is WAY better than the stuff available on the streets. The best stuff around here comes in medical bags... even though it is not legal... and is very expensive. Then there's "mids" which are affordable but sorta crappy. I have save a lot of money by growing my own over the years.

I have used this fact many times to justify spending money on growing equipment...

my friend

 

[Rodrigo]

Wow, that was extremely educational, kudos my friend you seem to have it down. That stuff about the H3PO4, never really stopped to think about it and one of my brothers studied some chemistry in college. I'll go back to it and start monitoring the pH on a regular bases. Also ordering a TDS meter like I had planned to like 6 months ago lol.
Although I may have to apologize to you because I already knew over half the stuff you put in there, like the how the pH work or what PPM meant, in this case what I meant to say with that I didn't know anything was just referring to not knowing what was the ideal target or how to know where to get it. or how to adjust
So sorry to have wasted your time a little bit but I really appreciate the effort, I did learn a lot and I think that if I can maintain the pH lower then maybe I could get better yields.

Its great to know that the coloring is most likely from the nutes, you could tell the water got lighter over the days.

I don't know if this changes anything about what you said, but I grow hydro, not in soil. My veg room is on a Drip (not really a drip, same system but water flows 3 times a day for 15 minutes each) and the flower room is on an Ebb & Flood system.

I have learned a lot, thank you. It's been quite the experience, never thought it would be this fun. Besides, if you're going to spend thousands of dollars in equipment you might as well do it right. I posted on a thread a few weeks ago of some guy who had at least 5-7 grand in equipment and had been trying to grow for a year to no avail because he was using 7 or 8 different bloom enhancer all at once on top of serious over watering, rookie mistakes.

I lost my clones of the AK-48 so I had to start from seed again, luckily I already have my first Blue Mystic and Aurora Indica ready for flower, they are almost two months old (sprouted on 5/25), and are about 35cm tall and really really bushy and since now I'll only have two this time in the new flower room (4x4x6 almost, instead of the old crappy 24"x24"x50") then I hope they'll grow a lot more because of the extra space. So I think I'm gonna start a journal. It'd be great to have your opinion and advice once I get it all set up and running. I'll also take the opportunity to challenge my GoPro and see if I can make a full timelapse.

Update, yesterday I noticed that the borders of some leaves are getting a little lighter (seem consistent and even) and today I noticed that probably about 20-30% of the thricomes are turning milky, so I'm thinking that the plants are reaching their maturity window, they were put in flower on 6/4 so just over week 6 and the strain is supposed to be 7-9, so far I've been harvesting at 8 weeks with almost full milky but little to no amber (closer to the none mark, actually). Although on the first grow the leaves never got lighter, but the thricomes were also almost all milky, and on the second (which I harvested early at 7 weeks) couldn't tell if the leaves were getting lighter because something else was causing that as well. So really no bases for comparison still.

Sorry for running long again and thank you for all your great advice and information!

 

[GreatLife4All]

You should definitely start a journal - I will definitely follow along and add whatever I can.

And it is OK that I didn't provide a complete education for you. It still is not wasted effort. A month or three from now some new person will find this thread and read it. And they may get more out of it than you did.