Is changing res water in dwc really necessary?

Budley Doright said:

Chiller for the win in a flooded system. And for the $10 it cost to change the res periodically I do it. When ph starts to fall I change, that can take anywhere from 14 to 5 days. Yes I use well water so that may effect stability also.

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chasingwaterfalls said:

I think the full res change between veg and flower is required if you're using different nutes once flowering begins? Haven't seen an issue with Lucas formula so far, so I guess that makes a difference

I guess I'd do the res change when swapping nutes, at the end of the flowering stretch

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OldMedUser said:

I got a DIY chiller good for two tubs at least. Good enough for $14.

I use RO water only and you can bet your well water does stuff to affect the stability depending on what's in it. Could be good or bad. Has it ever been analyzed?

My pH always used to rise over 3 days then I'd add 4 or 5 drops of concentrated sulfuric acid when I topped up. Go from 6.3ish to 5.4ish. That's actually good for them I've read all over but they don't get that with the pH Perfect and they grow fine.

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OldMedUser said:

Gabbed with Dallas, the lady that owns the hydro store I go to in Kelowna, for about an hour yesterday and she tried to order me some of the new organic nutes like the Ancient Earth but not in Canada eh. Her supplier says AN may not even bother getting them registered for sale in Canada as the market isn't big enough to justify jumping thru the regulatory hoops to get it here. If so I'll be looking for a new line of nutes in a year when I run out of these.

She's getting me in a 500ml jug of Bud Factor X so I can run a side-by-side and see if it's worth using regular. Should be here Sat. Might go seed shopping tomorrow at Hemp City but if not then next week some time.

Big f'n forest fire started this aft that's close enough to be a threat. Hope we don't have to bug out.

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rkymtnman said:

that's the spirit!

hydro is for growing, dirt is for racing.

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OldMedUser said:

Unfortunately the links to my past journals are home on my desktop and I'm here for 10 more days at least. Remind me.

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Airwalker16 said:

Can you elaborate on this DIY chiller ?

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JSB99 said:

You've got to get a remote app or cloud storage so you can access your computer/files from anywhere.

I use Team Viewer.

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Budley Doright said:

Ya I've been watching the shit show out there...bad! I spent 10 days last spring in the valley with myself driving around fishing in most of the rives awesome place! I saw the AE on amazon so the shipping may be rising the cost a bit lol.

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OldMedUser said:

It's just a water cooler that I took the guts out of the tank and I have a fountain pump in the tub that circulates the nutes up thru a coil of 3/8" tubing in that tank then back to the tub. I got the cooler for free and had the tubing already so it just cost me $14 for the little pump. I have a timer on the cooler so it doesn't get too cool and had to fiddle around with timing to get it right but it keeps the tub at 65F and can easily do another tub at least or a rez. I filled the cooler tank with antifreeze as water would actually freeze in there.

I'm out of town so can't put up any pics but I may have in my journal.

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OldMedUser said:

My grandad used to take me fishing in the Chilliwack river when I was about 3 - 8 when he passed. I know the valley and all the hidden hot spots on both sides of the Fraser river. Mid Oct to April was my fishing season for salmon and steelhead tho lots of trout the rest of the year. 50lb Chinook on the fly rod in the upper Chilliwack is hella fun!

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Budley Doright said:

Was there not a temp probe to control water temp originally? You can buy a dial temp probe for 20 bucks that you wire into power cord in series, probably work better.

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Budley Doright said:

Edit: oh right it's a dry cold. What the fuck, it's still cold lol

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OldMedUser said:

I've done DWC for 16 years and have tried changing regularly and not changing for the whole grow. I've run side-by-side tubs changing one a few times and not changing the other once with no difference in results or yields. I've settled on changing once after the stretch then just take out some of the nutes and replace with RO water to lower the ppm during later flower.

There is certainly no reason to change weekly when the plants are small and barely eating anything. You are just wasting perfectly good nutes and making more trips to the hydro store to make them richer.

This whole "gonna get different nutes off balance" is just malarkey. Never seen any deficiencies even when the nutes never got changed once. Not a great plan for a brand new grower but once you can read your plants fairly well it's easy-peasy.

I use the pH Perfect nutes and long ago retired my pH pen. I grow in single RubberMaid tubs so just have to top up, check ppm and boost nutes as needed to maintain the ppm level I want every 3 days with big plants.

Now if DWC would just cut flowering time in half like it does with veg times I'd have the best of all possible worlds.

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DrGhard said:

yes you definitely can. it is always recommended though to do at least one full ress change between veg and flowering.

- don't use beneficials. while their utility in DWC is questionable already, keeping them in a ress that you are not intending to change will lead to a lot of gunk buildup. while in theory those are not harmful micro-organisms, they do consume oxygen and nutrients in the ress iff things get out of control.

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vorus said:

I am currently planning on starting a 6 plant rdwc growth and I'll run some many ph perfect AN products in it (Sensi Grow+Bloom, B52, Voodoo Juice, Nirvana, Big Bud, Overdrive Rhino Skin, Bud Candy, Sensizyme). Now although I got the feeding chart from their website and calculated the amounts I'd need, what I'm not sure about is if they assume a weekly water change while adding these nutes or will I just top up the water, add these on top and go from there. And I've been thinking not to change the water except in between veg/flower as you suggested, but wouldn't that crank up my ppm if these amounts calculated are for freshwater weekly?
If what you suggest is not to add the nutes according to their plan but only while topping up and checking ppm, how would I be able to calculate how much to add from each of these many nutrients each time?
Also, if I don't top up the water every few days but wait for the end of the week, I'm worried the level might get so low, but on the other hand, wouldn't adding freshwater mess with my ph levels that were perfected with these AN products? I'm kinda lost as you can see




I was planning on using Voodoo Juice with so many great reviews around, but do you think they mostly come from people who change the res water from time to time? I think changing the res fully will start becoming a problem with a scrog net on top of the plants... Well I can pump the water out and refill it if needed of course, I'd do that at least in between stages, but taking out those buckets and doing a full clean wouldn't be so easy...

Also, this page suggests that doing a full water change might cause a shock and do more harm than good, and it's better to empty 50% of the res and add that much back in the system. But in between stages I'd have to do a full change anyway... so what would you guys think about this? Would it be so much of a shock to keep the buckets without water for 10-15 minutes while the old water is getting pumped out?

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vorus said:

I am currently planning on starting a 6 plant rdwc growth and I'll run some many ph perfect AN products in it (Sensi Grow+Bloom, B52, Voodoo Juice, Nirvana, Big Bud, Overdrive Rhino Skin, Bud Candy, Sensizyme). Now although I got the feeding chart from their website and calculated the amounts I'd need, what I'm not sure about is if they assume a weekly water change while adding these nutes or will I just top up the water, add these on top and go from there. And I've been thinking not to change the water except in between veg/flower as you suggested, but wouldn't that crank up my ppm if these amounts calculated are for freshwater weekly?
If what you suggest is not to add the nutes according to their plan but only while topping up and checking ppm, how would I be able to calculate how much to add from each of these many nutrients each time?
Also, if I don't top up the water every few days but wait for the end of the week, I'm worried the level might get so low, but on the other hand, wouldn't adding freshwater mess with my ph levels that were perfected with these AN products? I'm kinda lost as you can see

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OldMedUser said:

Talk about a blast from the past! lol

First thing is don't waste your money on all those supplements. All you need other than the base nutes is Big Bud and maybe some Rhino which will go bad within a year. Goes all green and gets lumps in it. It does work good with the PH Perfect tech tho. Any decent brand of CalMag will do and I use little of that and Epsom Salts are cheap. Bud Candy is overpriced sugar and really has no place in a hydro grow. I just feeds microbes in soil grows and you don't want those in a sterile hydro grow anyways. The only B vitamin the plants really need is B-1 and you can get a jar of those at the drug store, crush up a couple and toss the powder in the rez. I do that with those. zinc citrate, ascorbic acid, (vit C), a little citric acid, also from the drug store, and a couple of iron tablets. A mixed amino acid supplement too if you want more of those.

They do assume weekly water changes so you toss out perfectly good nutes and have to buy more sooner. Makes sense to them but not to my budget.

I mostly just calculated how much of each to add at top-up in my head. If my target ppm was 600 and after topping up with RO water, not tap, it was down to 450 I'd just use a bit of each to bring it back up. During vigorous veg growth I used a 3-2-1, (G,M,B), ratio of the 3-part as the plants want more of the N and less of the others. At one time I added 1ml of each to 1L of RO water to see how much ppm went up for each of the 3 parts but can't find my notes. Grow was the lowest, Bloom about 50% more than Grow and micro was 3x the Grow I believe. You could do the same then do a little basic algebra to get more exact calculations but a little common sense and basic math skills seemed good enough for me.

The ppm isn't that critical so if I was off 100 ppm either way I'd aim to go the other way at the next top-up. Good enough. If your RH is low then use less as the plants will drink a lot more water and get too many nutes if the ppm is higher. High RH then higher ppm as they drink less so get less nutes at a lower ppm.

Don't worry about the ppm dropping too low over a week. I just did the DWC in single tubs and every 3 days I'd top up with RO water then test ppm and adjust that. You should be able to do the same with RDWC.

This guy that just derided you for replying to an old post seems to have an RDWC grow so maybe check out his link to see what he's doing. He's probably just trolling for followers tho.

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OldMedUser said:

Talk about a blast from the past! lol

First thing is don't waste your money on all those supplements. All you need other than the base nutes is Big Bud and maybe some Rhino which will go bad within a year. Goes all green and gets lumps in it. It does work good with the PH Perfect tech tho. Any decent brand of CalMag will do and I use little of that and Epsom Salts are cheap. Bud Candy is overpriced sugar and really has no place in a hydro grow. I just feeds microbes in soil grows and you don't want those in a sterile hydro grow anyways. The only B vitamin the plants really need is B-1 and you can get a jar of those at the drug store, crush up a couple and toss the powder in the rez. I do that with those. zinc citrate, ascorbic acid, (vit C), a little citric acid, also from the drug store, and a couple of iron tablets. A mixed amino acid supplement too if you want more of those.

They do assume weekly water changes so you toss out perfectly good nutes and have to buy more sooner. Makes sense to them but not to my budget.

I mostly just calculated how much of each to add at top-up in my head. If my target ppm was 600 and after topping up with RO water, not tap, it was down to 450 I'd just use a bit of each to bring it back up. During vigorous veg growth I used a 3-2-1, (G,M,B), ratio of the 3-part as the plants want more of the N and less of the others. At one time I added 1ml of each to 1L of RO water to see how much ppm went up for each of the 3 parts but can't find my notes. Grow was the lowest, Bloom about 50% more than Grow and micro was 3x the Grow I believe. You could do the same then do a little basic algebra to get more exact calculations but a little common sense and basic math skills seemed good enough for me.

The ppm isn't that critical so if I was off 100 ppm either way I'd aim to go the other way at the next top-up. Good enough. If your RH is low then use less as the plants will drink a lot more water and get too many nutes if the ppm is higher. High RH then higher ppm as they drink less so get less nutes at a lower ppm.

Don't worry about the ppm dropping too low over a week. I just did the DWC in single tubs and every 3 days I'd top up with RO water then test ppm and adjust that. You should be able to do the same with RDWC.

This guy that just derided you for replying to an old post seems to have an RDWC grow so maybe check out his link to see what he's doing. He's probably just trolling for followers tho.

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