How often to do a Water Change in RDWC

[Pizzaguy2023]

I have a 25 gal RDWC set up, 3 tubs and 1 res. 3 plants I'm replenishing 5 gals a day, do I need to change the water? Or should I just add nutes when needed. I am using a chiller and running sterile.

 

[Smokey0418]

When I change to flower nutes , then about 30 days later.
I like to keep it simple, but my water is also chilled and I run bacteria.
Orca or better yet Hygroben.
Enjoy.

 

[Pizzaguy2023]

When I change to flower nutes , then about 30 days later.
I like to keep it simple, but my water is also chilled and I run bacteria.
Orca or better yet Hygroben

I've been doing full changes very week. Its been flowering now for 3 wks. Since ive been adding 5 gals a day the water has been crystal clear.

This is new for me

 

[Zeefarmer]

7 to 10 days complete pump out and change , total recharge..
Before the complete pump out I fill the reservoirs with fresh water for a couple hours
Check and adjust the PH everyday to every other day.

 

[Smokey0418]

Yes mine would also stay clear. During mid flower I would also be going though 20-30 gallons each week, so I’m more on the why throw out perfect good nutes .

Just so that I can purchase more?

I grow for myself so at this point I can’t consume it all so I will just keep it up.

My journals speak for themselves to the need of changing your water frequently.

No it doesn’t.

Enjoy and good luck with your grow.

 

[Pizzaguy2023]

Yes mine would also stay clear. During mid flower I would also be going though 20-30 gallons each week, so I’m more on the why throw out perfect good nutes .

Just so that I can purchase more?

I grow for myself so at this point I can’t consume it all so I will just keep it up.

My journals speak for themselves to the need of changing your water frequently.

No it doesn’t.

Enjoy and good luck with your grow.

Its for myself. 3rd grow, just want to make it as easy as possible with good results.

 

[Delps8]

Re. five gallons/day — that's a lot of water so that leads me to think that you're in flower. Is that correct?


I asked the same question when I started growing in 2021. I have a res that holds 28 gallons and it seemed absurd to "swap the res" every week. I have no reason to believe that X number of sunrises or sunsets makes nutrients unusable.

In the three years since then I've changed my processes (a lot). I top off with RO water or very weak (33%) strength nutes and will swap a res when I've replaced either the full amount of the res or, if I'm adding RO, when TDS has dropped by amount half, or if pH becomes unstable.

One thing that I had to get my head around is that, when a res drops from say, 800/500 PPM (I use PPM because it's more granular than TDS) to 600/500 PPM, that's a signficant percentage drop but there's still a lot of chemicals in res.

The plant will continue to take up nutrients, as well as exchange chemicals, because there's still quite a bit still in the res. I'm fairly OC about growing (if you read my grow journals you'll understand that I've taken some liberties when I use the word "fairly") so it took me a while to understand idea.

I don't add full strength nutrients because that can lead to a nutrient imbalance. My reason for making that statement is that the chemicals in cannabis nutrients are taken up at very different rates, some in hours while some take many days. By adding more full strength nutes, the plant is constantly getting more of the nutes that it just took up. That can move you from sufficiency to toxicity.

My reason for adopting those guidelines is because of the information int the attached documents.

The Bugbee paper discusses, among other things, the difference in the uptake rates of chemicals as well as the idea of using 33% strength nutes.

The CannaStats paper discusses the idea of swapping the res after topping off with a given volume of RO.

There's good info in both and they've allowed me to come up with a process that has worked well for me. I was swapping out my res every week to 10 days or 14 days and realize it was a complete waste of time. For my last few grows, I've only done three or four res swaps. Well, except for my last grow when, like a yutz, I tried a "bloom booster". Never again. A complete goat rope and of no value at all when growing in hydro.

One of the most interesting points was in the CannaStats paper where the author discusses res size vs canopy area. I use 28 gallons of nutes for 8 square feet and that ratio has worked out really well.


Again, many thanks to 420magazine for allowing us to upload PDF's.

 

[Pizzaguy2023]

Re. five gallons/day — that's a lot of water so that leads me to think that you're in flower. Is that correct?


I asked the same question when I started growing in 2021. I have a res that holds 28 gallons and it seemed absurd to "swap the res" every week. I have no reason to believe that X number of sunrises or sunsets makes nutrients unusable.

In the three years since then I've changed my processes (a lot). I top off with RO water or very weak (33%) strength nutes and will swap a res when I've replaced either the full amount of the res or, if I'm adding RO, when TDS has dropped by amount half, or if pH becomes unstable.

One thing that I had to get my head around is that, when a res drops from say, 800/500 PPM (I use PPM because it's more granular than TDS) to 600/500 PPM, that's a signficant percentage drop but there's still a lot of chemicals in res.

The plant will continue to take up nutrients, as well as exchange chemicals, because there's still quite a bit still in the res. I'm fairly OC about growing (if you read my grow journals you'll understand that I've taken some liberties when I use the word "fairly") so it took me a while to understand idea.

I don't add full strength nutrients because that can lead to a nutrient imbalance. My reason for making that statement is that the chemicals in cannabis nutrients are taken up at very different rates, some in hours while some take many days. By adding more full strength nutes, the plant is constantly getting more of the nutes that it just took up. That can move you from sufficiency to toxicity.

My reason for adopting those guidelines is because of the information int the attached documents.

The Bugbee paper discusses, among other things, the difference in the uptake rates of chemicals as well as the idea of using 33% strength nutes.

The CannaStats paper discusses the idea of swapping the res after topping off with a given volume of RO.

There's good info in both and they've allowed me to come up with a process that has worked well for me. I was swapping out my res every week to 10 days or 14 days and realize it was a complete waste of time. For my last few grows, I've only done three or four res swaps. Well, except for my last grow when, like a yutz, I tried a "bloom booster". Never again. A complete goat rope and of no value at all when growing in hydro.

One of the most interesting points was in the CannaStats paper where the author discusses res size vs canopy area. I use 28 gallons of nutes for 8 square feet and that ratio has worked out really well.


Again, many thanks to 420magazine for allowing us to upload PDF's.

hanks for the info. Im running auto's and they are in flower. iveT

Re. five gallons/day — that's a lot of water so that leads me to think that you're in flower. Is that correct?


I asked the same question when I started growing in 2021. I have a res that holds 28 gallons and it seemed absurd to "swap the res" every week. I have no reason to believe that X number of sunrises or sunsets makes nutrients unusable.

In the three years since then I've changed my processes (a lot). I top off with RO water or very weak (33%) strength nutes and will swap a res when I've replaced either the full amount of the res or, if I'm adding RO, when TDS has dropped by amount half, or if pH becomes unstable.

One thing that I had to get my head around is that, when a res drops from say, 800/500 PPM (I use PPM because it's more granular than TDS) to 600/500 PPM, that's a signficant percentage drop but there's still a lot of chemicals in res.

The plant will continue to take up nutrients, as well as exchange chemicals, because there's still quite a bit still in the res. I'm fairly OC about growing (if you read my grow journals you'll understand that I've taken some liberties when I use the word "fairly") so it took me a while to understand idea.

I don't add full strength nutrients because that can lead to a nutrient imbalance. My reason for making that statement is that the chemicals in cannabis nutrients are taken up at very different rates, some in hours while some take many days. By adding more full strength nutes, the plant is constantly getting more of the nutes that it just took up. That can move you from sufficiency to toxicity.

My reason for adopting those guidelines is because of the information int the attached documents.

The Bugbee paper discusses, among other things, the difference in the uptake rates of chemicals as well as the idea of using 33% strength nutes.

The CannaStats paper discusses the idea of swapping the res after topping off with a given volume of RO.

There's good info in both and they've allowed me to come up with a process that has worked well for me. I was swapping out my res every week to 10 days or 14 days and realize it was a complete waste of time. For my last few grows, I've only done three or four res swaps. Well, except for my last grow when, like a yutz, I tried a "bloom booster". Never again. A complete goat rope and of no value at all when growing in hydro.

One of the most interesting points was in the CannaStats paper where the author discusses res size vs canopy area. I use 28 gallons of nutes for 8 square feet and that ratio has worked out really well.


Again, many thanks to 420magazine for allowing us to upload PDF's.

Yes, in flower. Running autos, city water but its good (40ppm 7ph out of the tap). I've been giving nutes at 33%. I was changing water once a week but now I think I will wait and keep the PPM steady at 400

 

[Delps8]

Yes, in flower. Running autos, city water but its good (40ppm 7ph out of the tap). I've been giving nutes at 33%. I was changing water once a week but now I think I will wait and keep the PPM steady at 400

40 PPM - that's a gift! I had to go with RO or else it was 300PPM and variable.

Re. 400 PPM nutes - that's a good sign. A lot of growers use very high PPM's and I suspect it's because they need to do so to make up for something in their grow environment. My PPM's start at 200, then gradually go up to 800 and then back down. The Bugbee paper mentions how nutrient needs change over time in different parts of the paper. One comment of his is that they start their plants with high PPM because, paraphrasing, it's rare that young plants suffer from toxicity. And then there's the info that, toward the end, a few chemicals simply aren't used. I s'pose, if you're mixing your own, that's something to heed but with commercial nutes, we don't have much of a choice.

Thinking of that, what ferts do you use? I started with switched from Botanicare to Jacks and have no regrets. Part A + Part B + some Epsom makes it very easy to deal with. I also use a silica supplement, primarily because of what Bugbee says about it in his paper. If you're interested, check out the threads on nutes by @farside05. One is using one mixture from seedling to chop, another is mixing your own nutes. I decided to mix my own silica supplement his advice.

And I "drank the Koolaid" on the one formulation idea. His arguments seem sound and are in line with what Jack's recommends.

I did stray from the path for this last grow, however, and I completely regret it. I tried a bloom booster — "What could possibly go wrong?". There's dumb, and there's dumber, and there's "even dumber". Never again. pH went totally apeshit. It didn't drop, it plummeted. A complete pain in the ass and, as I later learned, pointless.

The "worthless" comment is based on two sources. Per Bugbee, plants take up P (or K - I've got a mental block on those) during early flower because they store that chemical in the flowers so it can be used by the seeds during germination. But I don't grow plants that have seeds so that's strike 1.

And, according to this site, K is so available in hydro that there's no value in a "booster". So that's pretty much game, set, and match on that idea (metaphors mangled at no extra charge).

The archives on the Fernandez site are very informative. The issue with K is in the attached paper.

 

[Pizzaguy2023]

40 PPM - that's a gift! I had to go with RO or else it was 300PPM and variable.

Re. 400 PPM nutes - that's a good sign. A lot of growers use very high PPM's and I suspect it's because they need to do so to make up for something in their grow environment. My PPM's start at 200, then gradually go up to 800 and then back down. The Bugbee paper mentions how nutrient needs change over time in different parts of the paper. One comment of his is that they start their plants with high PPM because, paraphrasing, it's rare that young plants suffer from toxicity. And then there's the info that, toward the end, a few chemicals simply aren't used. I s'pose, if you're mixing your own, that's something to heed but with commercial nutes, we don't have much of a choice.

Thinking of that, what ferts do you use? I started with switched from Botanicare to Jacks and have no regrets. Part A + Part B + some Epsom makes it very easy to deal with. I also use a silica supplement, primarily because of what Bugbee says about it in his paper. If you're interested, check out the threads on nutes by @farside05. One is using one mixture from seedling to chop, another is mixing your own nutes. I decided to mix my own silica supplement his advice.

And I "drank the Koolaid" on the one formulation idea. His arguments seem sound and are in line with what Jack's recommends.

I did stray from the path for this last grow, however, and I completely regret it. I tried a bloom booster — "What could possibly go wrong?". There's dumb, and there's dumber, and there's "even dumber". Never again. pH went totally apeshit. It didn't drop, it plummeted. A complete pain in the ass and, as I later learned, pointless.

The "worthless" comment is based on two sources. Per Bugbee, plants take up P (or K - I've got a mental block on those) during early flower because they store that chemical in the flowers so it can be used by the seeds during germination. But I don't grow plants that have seeds so that's strike 1.

And, according to this site, K is so available in hydro that there's no value in a "booster". So that's pretty much game, set, and match on that idea (metaphors mangled at no extra charge).

The archives on the Fernandez site are very informative. The issue with K is in the attached paper.

I'm using GH nutes.

 

[KBUENOS]

I have a 25 gal RDWC set up, 3 tubs and 1 res. 3 plants I'm replenishing 5 gals a day, do I need to change the water? Or should I just add nutes when needed. I am using a chiller and running sterile.

I change mine every three or four days, I like to use hydrogen peroxide to keep my stuff fresh and oxygenated, I also will use distilled water with ozone every so often, it keeps me from needing to clean half as much

 

[KBUENOS]

40 PPM - that's a gift! I had to go with RO or else it was 300PPM and variable.

Re. 400 PPM nutes - that's a good sign. A lot of growers use very high PPM's and I suspect it's because they need to do so to make up for something in their grow environment. My PPM's start at 200, then gradually go up to 800 and then back down. The Bugbee paper mentions how nutrient needs change over time in different parts of the paper. One comment of his is that they start their plants with high PPM because, paraphrasing, it's rare that young plants suffer from toxicity. And then there's the info that, toward the end, a few chemicals simply aren't used. I s'pose, if you're mixing your own, that's something to heed but with commercial nutes, we don't have much of a choice.

Thinking of that, what ferts do you use? I started with switched from Botanicare to Jacks and have no regrets. Part A + Part B + some Epsom makes it very easy to deal with. I also use a silica supplement, primarily because of what Bugbee says about it in his paper. If you're interested, check out the threads on nutes by @farside05. One is using one mixture from seedling to chop, another is mixing your own nutes. I decided to mix my own silica supplement his advice.

And I "drank the Koolaid" on the one formulation idea. His arguments seem sound and are in line with what Jack's recommends.

I did stray from the path for this last grow, however, and I completely regret it. I tried a bloom booster — "What could possibly go wrong?". There's dumb, and there's dumber, and there's "even dumber". Never again. pH went totally apeshit. It didn't drop, it plummeted. A complete pain in the ass and, as I later learned, pointless.

The "worthless" comment is based on two sources. Per Bugbee, plants take up P (or K - I've got a mental block on those) during early flower because they store that chemical in the flowers so it can be used by the seeds during germination. But I don't grow plants that have seeds so that's strike 1.

And, according to this site, K is so available in hydro that there's no value in a "booster". So that's pretty much game, set, and match on that idea (metaphors mangled at no extra charge).

The archives on the Fernandez site are very informative. The issue with K is in the attached paper.

sounds like you have a good city to live in, mine most always has reliable numbers, I have learned over time not to trust it blindly however as there has been a time or two where the water was out of whack

 

[Delps8]

sounds like you have a good city to live in, mine most always has reliable numbers, I have learned over time not to trust it blindly however as there has been a time or two where the water was out of whack

Sounds like "Trust but verify"!

I decided remove all doubt and go with RO in a 55 gallon cistern.

 

[KBUENOS]

ex-ac-tic-alley I see you did Glookies, I am going to check that out, thank you for sharing the wisdom