Frustrated w/ DWC + Lucas formula -- what is my issue?

[Liflow]

I wanted to start hydro simple, so I chose 5-gal bubbler bucket and Lucas' formula.

I have had constant problems with what appears to be a cal/mag deficiency. (Tiny yellow spots on the sunleaves)

Every time it happens, I dump my nutrient mix and start over w/ RO water and GH Micro/Bloom @ 8/16ml per gal. Everything looks good for a week or so, and then it starts getting wonky again: My PPMs will start to go up even though I'm topping off w/ just RO water. My water will also start getting cloudy / milky looking.

I'm wondering if I'm maybe having some kind of bacterial problem... So I tried using H2O2 but it has not helped. My PPMs still go crazy at about 1 - 1.5 weeks and I have to dump the batch and start over or the spots just get worse and leaves start dying.

So right now, my PPMs are 1340 @ .5, PH is 5.7, I haven't added any nutes since I mixed up the batch about a week ago. I am about 4 wks into 12/12 and I really don't want to lose my girl, she's looking pretty!!

What do I do? Dump my batch again? This is really getting old... I thought I could keep my nutes longer than a week...

Anyone have any idea of what's going on?

Thank you!

[Help_Needed]

Hi Liflow,

There are a lot of things to look at to try to figure out what's wrong with your grow. First, you didn't mention what type of lighting you have. That can be important when using the Lucas Formula. Also, if you're topping off with just pure R/O water, then you WILL need to change out your reservoir after you've added enough water to equal the original volume of your nute solution (5 gallons in your case). If you don't want to have change the res, then you need to use his add-back method. Look at the bottom half of the instructions on this post - http://forum.grasscity.com/advanced-...s-formula.html to see how to figure out how to mix up the nute solution.

Second, are you foliar feeding the plants? Small yellow spots doesn't actually sound like cal/mag deficiency. Cal/mag usually produces rust color spots, if it's the spotting your getting. Can you post some pics? That would help a lot.

Third, the water clouding up sounds like your nutrient solution is destabilizing for some reason. Your suspicion about a bacteria *may* not be incorrect, but there could be other causes. The rising PPM suggests that something else is getting into your reservoir. Are your roots healthy? Are you having to adjust the pH at all, or is it staying stable? What growing medium are you using? Where did you get the buck, airstones, pumps, etc that you're using? Anything else that might be unusual about your set up?

[Liflow]

Hi, thanks for your reply. I will try to answer your questions...

Originally Posted by Help_Needed

Hi Liflow,
First, you didn't mention what type of lighting you have.

400w air-cooled HPS.

Also, if you're topping off with just pure R/O water, then you WILL need to change out your reservoir after you've added enough water to equal the original volume of your nute solution (5 gallons in your case).

I only added 2 gallons... the latest Lucas post I read said to top-off with RO water throughout the week and then add nutes once a week to get the PPMs back to where they started... Since my PPMs are going crazy I have no idea how much nutes to add so I've just been dump and restarting every week...

Second, are you foliar feeding the plants? Small yellow spots doesn't actually sound like cal/mag deficiency. Cal/mag usually produces rust color spots, if it's the spotting your getting. Can you post some pics? That would help a lot.

No foliar feeding. Trying to keep this simple. They start out as small yellow spots and if I do nothing about it, they get bigger, turn brown and start killing the leaves. It looks exactly like the first pic of a calcium deficiency in this post after 4-5 days: http://www.icmag.com/ic/showthread.php?t=11688

But it starts out just looking like slightly yellowish polkadots.

Third, the water clouding up sounds like your nutrient solution is destabilizing for some reason. Your suspicion about a bacteria *may* not be incorrect, but there could be other causes. The rising PPM suggests that something else is getting into your reservoir. Are your roots healthy? Are you having to adjust the pH at all, or is it staying stable? What growing medium are you using? Where did you get the buck, airstones, pumps, etc that you're using? Anything else that might be unusual about your set up?

PH seems fairly stable. It starts at 5.5-5.6 with the fresh batch and drifts up to 5.8-5.9 after a week of topping off...

It's all kinda normal stuff as far as I know... 5 gallon white bucket covered in foil tape (both from hardware store), 6" ceramic air stones (2) from pet store and an EcoPlus dual-output air pump... Seems to make a TON of bubbles...

The roots looked healthy and white a week ago but I now have a scrog holding the plant and I'm not sure I can look in the bucket without damaging the plant...

Thanks again for your help...

[Help_Needed]

Originally Posted by Liflow

PH seems fairly stable. It starts at 5.5-5.6 with the fresh batch and drifts up to 5.8-5.9 after a week of topping off...

Hmmm...it shouldn't be drifting up like that. The lucas formula is normally much more stable. R/O water is usually pretty much pH inert. You have to add a lot of it to move the pH very far.

It's all kinda normal stuff as far as I know... 5 gallon white bucket covered in foil tape (both from hardware store), 6" ceramic air stones (2) from pet store and an EcoPlus dual-output air pump... Seems to make a TON of bubbles...

Lots of bubbles are good. As long as everything was new then it's probably not some sort of contamination. Are you using hydrotron, or something else?

The roots looked healthy and white a week ago but I now have a scrog holding the plant and I'm not sure I can look in the bucket without damaging the plant...

If you can figure out a way to take a peek without hurting the plant, I'd do so. Root rot is one of the things that will cause pH to shift upwards.

Otherwise, I'd double check the calibration of your pH meter and your TDS, just to be sure you're not having problems from faulty equipment.

Also, what are your res temps looking like?

[Liflow]

[quote=Help_Needed;2113051Lots of bubbles are good. As long as everything was new then it's probably not some sort of contamination. Are you using hydrotron, or something else?[/quote]

Yeah, germinated in 1.5" rockwool cubes, then put in 6" net pots filled w/ well-rinsed Hydroton.

Otherwise, I'd double check the calibration of your pH meter and your TDS, just to be sure you're not having problems from faulty equipment.

Yeah, I had thought of that, but the fact that it's been sort of a cyclical thing makes me think it's ok... It's pretty predictable, it all looks good for a week and then starts to go nuts. If I mix up a new batch, everything reads fine on my meters. The cloudy nutes happens around the same time that the PPM starts going nuts. I did add H2O2 this time (3ml/gal of 35%) hoping to combat it but it didn't stop or slow down the PPM climb.

Also, what are your res temps looking like?

Room varies from 60-75 deg F and the res has been 65-70 deg F for the last month...

I don't know if this has anything to do with it, I have a separate 2 gal bucket and a pump that I use to recirculate. I do this for convenience. I run the pump for a few minutes and check pH/TDS in the little bucket so I don't have to disturb the plant. I had 3 buckets originally but 2 plants turned out to be males so now there's only 1 5-gal bucket connected to the 2 gal "access bucket".

After this time I think I'm going to play with an Ebb/Flow tray... I'm just not crazy about DWC so far, I feel like my plant is constantly going between doing really well and on the verge of dying...maybe I'm just overreacting...

[Help_Needed]

Wow...I'm at a loss. Your temps are fine (65-70 is perfect, btw). Your medium is fine. Your pH is good, if less stable than it should be. In short, you're not making any of the normal mistakes that would cause problems.

Your PPM is spiking, though, which makes me think that *something* is getting into the reservoir and destabilizing your nutrient solution. You'll sometimes see the water turn cloudy like yours is doing if you add a lot of pH adjusters in, for example. But from the sound of it, you're not getting a chance to adjust the pH before the TDS goes wrong.

Is there any possible outside source of contamination? Is your secondary reservoir open to the air, by chance? Would it be possible to quit using the secondary res for a while, and maybe just use the drain tube and leave the main res sealed off?

Otherwise, I'm stumped. Maybe someone else has a suggestion?

P.S. DWC systems usually have a very good track record, in part because they're so very simple. A lot of growers have had good results from them. I'm guessing that there's something unique to your set up that's causing the problem.

[dunumptanum]

Not that I am a hydro expert by any means, but when you balance your PH are you using proper PH up and down mixtures (and not vinegar/bicarb etc)?

Also, do you use both products in one mixing? (The reason I ask is that apparently you should try to only use one product at a time, if you add too much of either mixture and overshoot your desired PH you should dump your nutes and remix them, instead of using the opposite product to balance it out).


Also, I am assuming that you built your own DWC buckets? What sealant/glue did you use? Is it possible that some of it is breaking down and leeching into your nutes? What about the foil tape, is any of the adhesive sticky side touching the nutes? Hearing about the cloudy reservoir makes me think that something contaminating it for sure...

Good luck, and peace!

[Liflow]

Originally Posted by Help_Needed

You'll sometimes see the water turn cloudy like yours is doing if you add a lot of pH adjusters in, for example. But from the sound of it, you're not getting a chance to adjust the pH before the TDS goes wrong.

Yeah, I don't put anything in but the GH Micro/Bloom at 8/16...

Is there any possible outside source of contamination? Is your secondary reservoir open to the air, by chance? Would it be possible to quit using the secondary res for a while, and maybe just use the drain tube and leave the main res sealed off?

Nope, it's closed, lid is set on it properly but not latched down. It would have to be a lot of crud falling in it to make the PPM jump that much happen though, wouldn't it?

I had thought about disconnecting the second res and just dealing with the inconvenience to try to simplify the system... Like, maybe water is getting trapped in the fill hose and growing algae or something...? It's polypropelene tubing, the kind used for sprinkler systems but it is almost level at the top of the hook where it comes off the pump into the top of the bucket so water could be sitting in it for a day between times that I run the pump to recirc the nutes.

P.S. DWC systems usually have a very good track record, in part because they're so very simple. A lot of growers have had good results from them. I'm guessing that there's something unique to your set up that's causing the problem.

Yeah, I pretty much followed Rumpleforeskin's "how-to" thread to the letter... Had some issues where I bought the wrong hose barbs and ended up having to use sprinkler tubing instead of clear/white flexible vinyl tubing though...

Originally Posted by dunumptanum

Not that I am a hydro expert by any means, but when you balance your PH are you using proper PH up and down mixtures (and not vinegar/bicarb etc)?

I'm using Lucas' formula. It doesn't typically need pH adjustment from what I understand of it... I'm not doing any pH adjustment and it ends up right where I want it (my meter reads 5.6) when mixed at 8ml/16ml per gallon.

Also, do you use both products in one mixing? (The reason I ask is that apparently you should try to only use one product at a time, if you add too much of either mixture and overshoot your desired PH you should dump your nutes and remix them, instead of using the opposite product to balance it out).

Yeah, that makes sense. But that's not really relevant here. I'm not fighting a pH problem, oddly, I'm fighting a PPM problem...

Also, I am assuming that you built your own DWC buckets? What sealant/glue did you use? Is it possible that some of it is breaking down and leeching into your nutes? What about the foil tape, is any of the adhesive sticky side touching the nutes? Hearing about the cloudy reservoir makes me think that something contaminating it for sure...

Nope, no adhesives, I used O-rings like in Rumpleforeskin's sticky thread. The foil tape isn't touching the nutrients anywhere. It's completely on the outside of the buckets...

I guess I'll just dump the nutrients again and start over like I've been doing... I just expected it to be more stable based on what I've read about this technique and formula...

Thanks for your help, guys!

[Liflow]

You know, I just thought of something...

I did use teflon tape on the threaded fittings. (Not the ones w/ O-rings, the other ones)

Does that stuff disolve in nutrient mixes or is it safe to use?

[Help_Needed]

Originally Posted by Liflow

You know, I just thought of something...

I did use teflon tape on the threaded fittings. (Not the ones w/ O-rings, the other ones)

Does that stuff disolve in nutrient mixes or is it safe to use?

Good question. On the one hand, that stuff's designed to be used in household plumbing, so you'd think it should be pretty inert. On the other hand, raw nutrient solution is pretty acidic. Maybe it's possible it's dissolving the tape?

As for the algae, as long as your tubing is black, you shouldn't have any. Algae needs light, just like any other plant.

One other idea that occurred to me - test your pH and TDS of your R/O water before you add any nutes. Maybe something's wrong with the R/O system your using and your water isn't clean.

[Liflow]

Yeah, I always test the water. I don't own the RO system, I buy the water.

It registers 3-5 PPM on my TDS meter.

The pH flashes 7.0 and 7.1 and then settles at 7.0 if I leave it in the water for a few seconds.

I usually rinse it in the same RO water to clean the meter and also verify the reading I just took.

I have a cheap Milwaukee pH600 meter but I haven't had any problems with it so far. I don't expect it to last long but it seems to have worked fine for the last 2 monthes.

I'm just going to dump the water and start over. It's frustrating but I just don't see another way around it at this point...

[Help_Needed]

Damn, dude. Don't know what else to say .

It's pretty obvious that *something* is getting in your solution and messing it up, but I have no idea what.

[durty nugget]

i think your ph should be lower. Like 5.5-6.5....try to keep the pH lower in hydro setups..

[linedrivr]

Originally Posted by Liflow

I wanted to start hydro simple, so I chose 5-gal bubbler bucket and Lucas' formula.

I have had constant problems with what appears to be a cal/mag deficiency. (Tiny yellow spots on the sunleaves)

Every time it happens, I dump my nutrient mix and start over w/ RO water and GH Micro/Bloom @ 8/16ml per gal. Everything looks good for a week or so, and then it starts getting wonky again: My PPMs will start to go up even though I'm topping off w/ just RO water. My water will also start getting cloudy / milky looking.

I'm wondering if I'm maybe having some kind of bacterial problem... So I tried using H2O2 but it has not helped. My PPMs still go crazy at about 1 - 1.5 weeks and I have to dump the batch and start over or the spots just get worse and leaves start dying.

So right now, my PPMs are 1340 @ .5, PH is 5.7, I haven't added any nutes since I mixed up the batch about a week ago. I am about 4 wks into 12/12 and I really don't want to lose my girl, she's looking pretty!!

What do I do? Dump my batch again? This is really getting old... I thought I could keep my nutes longer than a week...

Anyone have any idea of what's going on?

Thank you!

Hey Liflow,

if your post above is not a type error, then you are burning your plants. 1340ppms @ .5 conversion is over 2.6EC. You should be under 2.0EC.

bring your ppms down under 1000 @ .5 conversion. Are you having to add PH up or down to your reservoir or topoffs?

Regards,
linedrivr

[linedrivr]

"What do I do? Dump my batch again? This is really getting old... I thought I could keep my nutes longer than a week..."

for what it is worth, I am 5 weeks into flowering now using a 4 bucket dwc system + 14 gal reservoir and have not had to dump/change my reservoir since I started this grow including veg time. I top off w/ pure RO all week and adjust nutes back up 1350 - 1400 (.7 conversion) on Saturdays. I dont have to add much micro and bloom to keep it at the 1300 - 1400 level (1000 or less in your case @ .5 conversion).

I have yet to need to add PH up or down. Mine stays between 5.4 - 6.1 all week. It climbs during the week while topping with PH 7.3 RO then drops when I feed micro/bloom on saturdays. Lucas claims that the PH swing from low 5's to low 6's is good for the plants to be able to uptake their needed nutrients.

with this being said, I have found that with the Lucas feeding schedule using GH micro/bloom, I have to add a pinch of epsom salts to the reservoir every couple weeks to keep from having magnesium def. I add 1ml per gallon in the system. I disolve it first in a gallon jug then pour into the reservoir. I have a magnetic driven water pump that re-circulates my nutes through the system and the magnet in it attracts my magnesium....lol

regards,
linedrivr