Can you run a recirculating reservoir for 2 weeks...?

General rule of thumb has always been when you have replaced the entire volume with fresh water its time to change. I let my rez go due to lazyness many times, what i notice is i get a build up of plant waste in the bottom of the rez. A fresh rez at the right time is essential to high performance growing, if you dont go hard and fast, i dont know what one does but i imagine not changing your rez regularly would be policy..

Something that might help is getting a

CharlieBravo said:

Is it safe to assume that the smaller the amount of water (ex 5gal) the more frequent you need to change reservoir water than for a larger size (ex 15 gal?) Or are other factors more important to determine when to change out the water?

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There are a couple things you can do to get around having to use smaller containers for your plants.

You can have a large reservoir in a remote location, outside of a tent, for example.
Another option is to have a second reservoir that can be used to keep your controller reservoir topped off. This can be done with a pump and a float valve, if the secondary reservoir has to be at ground level, or just a float valve if you can raise the secondary reservoir so that it's gravity-fed. The float valve goes on your controller reservoir and can be adjusted for different levels.

All depends on volume mate, massively oversized res can last a month in my experience. If u need to adjust ph more than once a week ur res is too small or you’ve got ur ppm way off anyways.

I have literally seen some of the worst advice in this thread ever. Change you water when the ppm drop below a certain point, depends on the strain. Some like it hot constantlty some like it in waves. You will know by the leaves and by metering your ppm twice a day atleast.

For starters the plant prioritizes N uptake over everything else, so if there is useable N in your rez it will uptake it. If you top up with nutes you have no way of knowing what salts are missing and what are building up. The example if you keep topping up dailing with nute water the plant will continually consume the N and grow lonmg weak stems. If you never flush or rarely flush then you can have salt build ups. Depending on if you are doing a DWC with a fresh water rez or if you are doing RDWC you should be flushing the system every week in veg and in late flower twice a week...depending on how much finishing powder you are using and how it is responding to it.

Would love to see facts on that

If i recall the direct absorbtion of nitrogen
Is directly related to the uptake of other nutrients
Iron being one if i recall there are about 2 more that also directly affect nitrogen uptake

Per harvey smith look up his vids he can explain it better than i

Twerkle said:

I have literally seen some of the worst advice in this thread ever. Change you water when the ppm drop below a certain point, depends on the strain. Some like it hot constantlty some like it in waves. You will know by the leaves and by metering your ppm twice a day atleast.

For starters the plant prioritizes N uptake over everything else, so if there is useable N in your rez it will uptake it. If you top up with nutes you have no way of knowing what salts are missing and what are building up. The example if you keep topping up dailing with nute water the plant will continually consume the N and grow lonmg weak stems. If you never flush or rarely flush then you can have salt build ups. Depending on if you are doing a DWC with a fresh water rez or if you are doing RDWC you should be flushing the system every week in veg and in late flower twice a week...depending on how much finishing powder you are using and how it is responding to it.

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But my EC doesn't drop? It actually climbs slowly so then what lol. I actually watch PH and when after a period of time it will start to drop off slowly as opposed to rising, that's typically when I change and that can be anywhere from 1 week to 3 weeks in the beginning. I also will change if the levels get to low in my ebb&flow. So if I'm running 50 gallons your saying I need to change it every 3-4 days regardless of plant numbers?

Budley Doright said:

But my EC doesn't drop? It actually climbs slowly so then what lol. I actually watch PH and when after a period of time it will start to drop off slowly as opposed to rising, that's typically when I change and that can be anywhere from 1 week to 3 weeks in the beginning. I also will change if the levels get to low in my ebb&flow. So if I'm running 50 gallons your saying I need to change it every 3-4 days regardless of plant numbers?

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Your ec should never drop considerably if at all, ph rise and ec rise as plants drink nutes and water in the correct ratios

Twerkle said:

I have literally seen some of the worst advice in this thread ever. Change you water when the ppm drop below a certain point, depends on the strain. Some like it hot constantlty some like it in waves. You will know by the leaves and by metering your ppm twice a day atleast.

For starters the plant prioritizes N uptake over everything else, so if there is useable N in your rez it will uptake it. If you top up with nutes you have no way of knowing what salts are missing and what are building up. The example if you keep topping up dailing with nute water the plant will continually consume the N and grow lonmg weak stems. If you never flush or rarely flush then you can have salt build ups. Depending on if you are doing a DWC with a fresh water rez or if you are doing RDWC you should be flushing the system every week in veg and in late flower twice a week...depending on how much finishing powder you are using and how it is responding to it.

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The flushing comment is bs I say, if ur feeding the correct amounts u don’t need to flush, I will agree on what u say about adding nute solution back into the res as a top up, to do this properly you need a mass spectrometer and base nutrients to adjust each element.

Are u seriously saying that if I only have one plant and a 400l recirculating res, that plant will take nitrogen til there’s none left causing n tox even though my ec is bang on? Sorry mate but I’ve been doing this a while and I know from experience this isn’t the case, I can’t give u paper evidence. But I’ve been running massively oversized Rezs for years and now have zero problems with nutrients as opposed to the constant n tox you’re describing

Blue brother said:

Your ec should never drop considerably if at all, ph rise and ec rise as plants drink nutes and water in the correct ratios

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That's exactly what happens in my res. that's why I asked about his method of changing res. my PH when it's time to change will start to drop and becomes unstable. Topping up brings it back but it will still keep dropping so I just change it out, works well for me but I'm sure everyone is a bit different due to water makeup

Budley Doright said:

That's exactly what happens in my res. that's why I asked about his method of changing res. my PH when it's time to change will start to drop and becomes unstable. Topping up brings it back but it will still keep dropping so I just change it out, works well for me but I'm sure everyone is a bit different due to water makeup

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Yeah ur ph will drop, that’s cos there’s not enough nutrients left in the solution.

A greater amount of solution in the first place will see you through that bit longer without having to adjust. Il be honest I adjust once a week And add fresh tap water or change res every 2 weeks. When the plants are in veg and they’re getting little and often feedings I’ve seen me go 4 weeks with only 3 adjustments and 1 top up of fresh water, and I know from experience I could use an even bigger res and not have to touch it for a month.

I’m not sure how long a and b nutrients would last mixed together without reactions rendering some compounds unavailable to the plant but I know from experience that what I do works. That’s all I need to know really, my plants never want for anything and they’re allways growing at optimum rate.

Temperature plays a part too, the colder means more oxygen, the warmer means more efficient root function and nutrient uptake. My happy medium sits slightly on the warm side, at a controlled 21’c. I use an aquarium ozone generator and bleach for pathogen control though, bennies would probs do a better job in a cooler solution though. Just some food for thought

Blue brother said:

Yeah ur ph will drop, that’s cos there’s not enough nutrients left in the solution.

A greater amount of solution in the first place will see you through that bit longer without having to adjust. Il be honest I adjust once a week And add fresh tap water or change res every 2 weeks. When the plants are in veg and they’re getting little and often feedings I’ve seen me go 4 weeks with only 3 adjustments and 1 top up of fresh water, and I know from experience I could use an even bigger res and not have to touch it for a month.

I’m not sure how long a and b nutrients would last mixed together without reactions rendering some compounds unavailable to the plant but I know from experience that what I do works. That’s all I need to know really, my plants never want for anything and they’re allways growing at optimum rate.

Temperature plays a part too, the colder means more oxygen, the warmer means more efficient root function and nutrient uptake. My happy medium sits slightly on the warm side, at a controlled 21’c. I use an aquarium ozone generator and bleach for pathogen control though, bennies would probs do a better job in a cooler solution though. Just some food for thought

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I did run beanies but have stopped, I keep my res at 66-67 and canopy at 75-78 lights on. I only use an A+B and Vitanimo, which due to water make up (well) seems to help with cal/mag issues and leaf blotching.

Uh i thought ph was supposed to rise and ec fall
Im no scientist though lol

CharlieBravo said:

Is it safe to assume that the smaller the amount of water (ex 5gal) the more frequent you need to change reservoir water than for a larger size (ex 15 gal?) Or are other factors more important to determine when to change out the water?

Click to expand...

Well the idea behind changing out is plants don't take in at the same ratios you are feeding. I guess if you were in a lab, had fancy equipment and ran the same strain will all the same environement you could figure out what the plant is leaving behind and edit your top offs accordingly. Most don't have that luxury. I digress. So yeah the idea is to flush and start fresh cause with top offs you will run into excess of certain nutrient ts your plant is using less of. This is exacerbated by using incorrect ratios to start.

Think of it this way. For lunch you need an apple, a salad a slice of cheese and a piece of steak to survive. You get 2 apples a salad cheese and steak. That extra apple is left. Next day you get the same. Now you have 2 extra apples. And so on. But say if you have too many apples in your lunchbox is affects your absorption of the cheese. Well eventually with enough excess apples it's going to cause you to not be able to absorb that cheese due to the protagonist is and antagonistic traits of those foods.

Nutrienta are the same way.

If you look at the grow a pound every three weeks thread. I think he uses an 18 gal tote for 3 weeks at a time. So only 3 times you have to mix up fertilizer.

Cold$moke said:

If i recall the direct absorbtion of nitrogen
Is directly related to the uptake of other nutrients
Iron being one if i recall there are about 2 more that also directly affect nitrogen uptake

Per harvey smith look up his vids he can explain it better than i

Click to expand...

Mueller's chart explains this for all 16 nutrient ts

Budley Doright said:

But my EC doesn't drop? It actually climbs slowly so then what lol. I actually watch PH and when after a period of time it will start to drop off slowly as opposed to rising, that's typically when I change and that can be anywhere from 1 week to 3 weeks in the beginning. I also will change if the levels get to low in my ebb&flow. So if I'm running 50 gallons your saying I need to change it every 3-4 days regardless of plant numbers?

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if your ec is going up that means u are over feeding. EC should stay the same if your plants are drink water and nutes at equal levels or drop if they are drinking more nutes than water. Its common sense lol. Also they should have a range, usually between 30 and 50% ec drop before change or every weak, which ever is sooner.

Don't mean to hijack the op's thread but as a noobie wasn't sure where to get help getting a definitive answer to this. What exactly does a rising or falling ec and ph levels mean. From what reading I've done, mostly from internet sites like these, I can't seem to get a definite answer, hope someone here can help.
1.A rising ec and a falling ph means the Rez is too hot and there's too strong of a solution for the plants and are consuming more water than nutes, thus making the solution more concentrated.
2. A falling ec and a rising ph indicates the Rez is too weak and is consuming more nutes than water thus reducing the concentration of the rez solution.
3. A relatively stable ec and ph indicates that the rez is pretty much at the proper concentration and is at proper equilibrium and is pretty much at the happy medium for the plants.
I am not sure where I came up with this thought of thinking, but remember reading it on a few different sources from around the net. My question to all you experienced growers out there, is this train of thought right? Any help would be greatly appreciated to help clarifying this with me. Thanks!!

firsttimeARE said:

Well the idea behind changing out is plants don't take in at the same ratios you are feeding. I guess if you were in a lab, had fancy equipment and ran the same strain will all the same environement you could figure out what the plant is leaving behind and edit your top offs accordingly. Most don't have that luxury. I digress. So yeah the idea is to flush and start fresh cause with top offs you will run into excess of certain nutrient ts your plant is using less of. This is exacerbated by using incorrect ratios to start.

Think of it this way. For lunch you need an apple, a salad a slice of cheese and a piece of steak to survive. You get 2 apples a salad cheese and steak. That extra apple is left. Next day you get the same. Now you have 2 extra apples. And so on. But say if you have too many apples in your lunchbox is affects your absorption of the cheese. Well eventually with enough excess apples it's going to cause you to not be able to absorb that cheese due to the protagonist is and antagonistic traits of those foods.

Nutrienta are the same way.

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But don't the nutrients come already at the correct ratio for MJ?

I never change my res water only top off

Tjs1989 said:

But don't the nutrients come already at the correct ratio for MJ?

I never change my res water only top off

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MJ needs change throughout the grow cycle. Which is why feeding schedules have you varying the amounts