Interveinal chlorosis, rust spots, edge burn

4 bruce banner plants in dwc. 4 phenos from seed. Grow room conditions pretty much perfect. 75f, 60RH, good intake of fresh air, good air movement, res temp 68f.
Plants look overall pretty healthy but all 4 have slight interveinal yellowing on older growth only, those leaves also have some necroses/burn randomly around edges, not concentrated at tip. One plant also has small brown/rust colored spots on pretty much all leaves except for very newest growth. To me it sounds like symptoms of both magnesium and calcium deficiency. The thing is, ive been giving them what i thought was a pretty good amount. Running GH flora with calimagic in ro water. I start out with about 250ppm of calimagic, then bring it up to about 450 total with other 3 parts. These are 4 week old plants in dwc so they dont need much ppm. I feel like 250ppm of calmag is already high, most guys say 100-200, although i am still below GH recommended amount with 250ppm. GH says 5ml per gallon but thats like 350ppm before even adding any other nutes which just seems like too much for dwc. The symptoms tell me they want more calmag, but i just dont know for sure. Should i go higher or could this be another problem? Pics attached.

What's the PH? A PH over 6 can lock out iron in a water grow and cause interveinal chlorosis, but some people can run that high and be OK. I veg 5.8 to 6.0 and flower 5.4 to 5.6.

I agree with the above. I always change ph first and see if that helps. I’ve never had luck with adding more calmag as you say 250 ppm should be enough.

I range from 5.8 to 6.2. I try to let it wander back and forth a bit. Over 6 locks out iron, but ive also heard under 6 locks out calmag. Either way, i think ive given enough range between 5.8 and 6.2 for ph to not be an issue.

DWCgrower406 said:

I range from 5.8 to 6.2. I try to let it wander back and forth a bit. Over 6 locks out iron, but ive also heard under 6 locks out calmag. Either way, i think ive given enough range between 5.8 and 6.2 for ph to not be an issue.

Click to expand...

Your RO water. So maybe it’s low? You could up food a bit and see. That’s about the only thing you can change. Your N part of your nutes has Ca in it. Another thing you can try is adding Epsom for Mg. I usually add 8 grams to 12 gallons to my tap water. On top of my calmag.

I don't think adding more calmag will help-in most cases like this i've seen in the past, the calmag was part of the problem. Okay, first thing, double check your ph pen against calibration fluid. I've always had good success in letting the PH wander through a range too, so my next suggestion would be to increase the range. Next, I'd lower the calmag and then see what happens over the next week. If you have access to an amino acid supplement, I'd also try that-any hydrolized protein powder or liquid supplement will work-even something like Neptune's harvest. Next best would be a basic soy protein powder with nothing added-1/4 teaspoon per gallon. If you like Amazon, I've used the GH Plant Foods protein before, but I think it's just soy protein. Sometimes aminos will fix these mysterious "calmag" issues. Fulvic acid is worth trying too-I like Mr. Fulvic, works better for me than BioAg, but honestly I think it's just because it's more concentrated.

Ok, thanks guys. Ive been religiously checking my pens since the start of the grow. I bought a pile of the ph calibrator packets so i check against one if those at least once per week. Been calibrating my tds to a 1000ppm solution but i found out yesterday that wasnt good enough. Decided to also order 342 ppm solution since its closer to what im feeding at and i was 80ppm off even though i was dead on at 1000. So i recalibrated at 342ppm and it turns out i havent been giving as much calmag as i thought. Probably closer to 180ppm. In most cases i would think that should still be enough, but ive decided to first try upping calmag a bit and broadening the ph swing, like maybe 5.7 to 6.3, see what happens. Unfortunately its kinda hard to see definitive changes in the spots very quickly. New growth always looks perfect. Once leaves reach maybe 2 to 3 inches in length, there may be a spot or 2 out towards tips. As they get older and larger, the spots increase in number and move towards base of leaf. I think im gonna have to be more thorough in documentation to see changes. Like tag specific leaves and take pictures, note how large they are when spotting starts, re evaluate a few days later. Only one plant has the spotting. All 4 have interveinal chlorosis on much older leaves, but its pretty mild on most. Night before last i brought everything up to 500ppm total including the larger dose of calmag, probably a true 250-275 rather than the 180 i gave before. This morning everything looked good, drank about a half gallon each and were all down to about 450ppm, so i would say they were hungry in general. Too early to tell if deficiencies are improving, we will see. Not gonna stress too much. Im gonna have huge excess on this grow. I plan to pick best pheno and do another from clones this fall.

DWCgrower406 said:

4 bruce banner plants in dwc. 4 phenos from seed. Grow room conditions pretty much perfect. 75f, 60RH, good intake of fresh air, good air movement, res temp 68f.
Plants look overall pretty healthy but all 4 have slight interveinal yellowing on older growth only, those leaves also have some necroses/burn randomly around edges, not concentrated at tip. One plant also has small brown/rust colored spots on pretty much all leaves except for very newest growth. To me it sounds like symptoms of both magnesium and calcium deficiency. The thing is, ive been giving them what i thought was a pretty good amount. Running GH flora with calimagic in ro water. I start out with about 250ppm of calimagic, then bring it up to about 450 total with other 3 parts. These are 4 week old plants in dwc so they dont need much ppm. I feel like 250ppm of calmag is already high, most guys say 100-200, although i am still below GH recommended amount with 250ppm. GH says 5ml per gallon but thats like 350ppm before even adding any other nutes which just seems like too much for dwc. The symptoms tell me they want more calmag, but i just dont know for sure. Should i go higher or could this be another problem? Pics attached.

Click to expand...

That looks like classic calcium deficiency. Your fertilizer ratios may be out of whack. With the flora series in RO water your res should be at an EC of 1.6-1.8 or about 700-850. Otherwise the plants look nice and healthy. Just a fertilizer balance issue is what I'm seeing. @rkymtnman does DWC and knows his shit with that method of growing. Maybe reach out to him or maybe he'll pop in to offer his $.02.

jonnynobody said:

That looks like classic calcium deficiency. Your fertilizer ratios may be out of whack. With the flora series in RO water your res should be at an EC of 1.6-1.8 or about 700-850. Otherwise the plants look nice and healthy. Just a fertilizer balance issue is what I'm seeing. @rkymtnman does DWC and knows his shit with that method of growing. Maybe reach out to him or maybe he'll pop in to offer his $.02.

Click to expand...

Yeah im thinking so as well, especially since i found out my ppm was reading high at lower numbers. Wasnt giving as much calmag as i thought. I brought it up night before last, so far they seem to like it, we will see in time. rkymtnman has been really helpful in my other threads about dwc, we'll see what he says.

DWCgrower406 said:

4 bruce banner plants in dwc. 4 phenos from seed. Grow room conditions pretty much perfect. 75f, 60RH, good intake of fresh air, good air movement, res temp 68f.
Plants look overall pretty healthy but all 4 have slight interveinal yellowing on older growth only, those leaves also have some necroses/burn randomly around edges, not concentrated at tip. One plant also has small brown/rust colored spots on pretty much all leaves except for very newest growth. To me it sounds like symptoms of both magnesium and calcium deficiency. The thing is, ive been giving them what i thought was a pretty good amount. Running GH flora with calimagic in ro water. I start out with about 250ppm of calimagic, then bring it up to about 450 total with other 3 parts. These are 4 week old plants in dwc so they dont need much ppm. I feel like 250ppm of calmag is already high, most guys say 100-200, although i am still below GH recommended amount with 250ppm. GH says 5ml per gallon but thats like 350ppm before even adding any other nutes which just seems like too much for dwc. The symptoms tell me they want more calmag, but i just dont know for sure. Should i go higher or could this be another problem? Pics attached.

Click to expand...

Looks like the start of calmag
Ph your res to 6-6.2 (cal n mag are both taken up perfectly at 6.2)
Higher your ppm too, 0.8-1.0

DWCgrower406 said:

Yeah im thinking so as well, especially since i found out my ppm was reading high at lower numbers. Wasnt giving as much calmag as i thought. I brought it up night before last, so far they seem to like it, we will see in time. rkymtnman has been really helpful in my other threads about dwc, we'll see what he says.

Click to expand...

Please do invest in a quality PH meter with remote probe via BNC connector. Meters like this can use any BNC style PH probe for replacements in the future. Milwaukee MW102 is solid as are the Apera and HM units on the more affordable end of the spectrum. I've had my MW102 for over 2 1/2 years and it works just as well as the day I got it. I eventually upgraded because I kept fucking my plants up due to my cheap PH meter displaying incorrect values which fucked up my plant's fertilizer ratios. I just got tired of a piece of equipment ruining my results. Get 4.0 and 7.0 calibration solution as well so you can perform a 2 point calibration to ensure accuracy of your readings. Grab PH probe storage solution also. It's usually just KCI. Cheap stuff. Prolongs the life of your probes.

DWCgrower406 said:

Yeah im thinking so as well, especially since i found out my ppm was reading high at lower numbers. Wasnt giving as much calmag as i thought. I brought it up night before last, so far they seem to like it, we will see in time. rkymtnman has been really helpful in my other threads about dwc, we'll see what he says.

Click to expand...

what ratios are you running your micro/grow/bloom at?

and i'm assuming you mix your cal/mg first and then micro 2nd?

jonnynobody said:

Please do invest in a quality PH meter with remote probe via BNC connector. Meters like this can use any BNC style PH probe for replacements in the future. Milwaukee MW102 is solid as are the Apera and HM units on the more affordable end of the spectrum. I've had my MW102 for over 2 1/2 years and it works just as well as the day I got it. I eventually upgraded because I kept fucking my plants up due to my cheap PH meter displaying incorrect values which fucked up my plant's fertilizer ratios. I just got tired of a piece of equipment ruining my results. Get 4.0 and 7.0 calibration solution as well so you can perform a 2 point calibration to ensure accuracy of your readings. Grab PH probe storage solution also. It's usually just KCI. Cheap stuff. Prolongs the life of your probes.

Click to expand...

Agreed 100%, good grow starts with good instruments and ive been putting it off way too long. I think i have been at least very close since i calibrate with 6.86 at least weekly, but it could still be off slightly without the 4.0.
Plan was to get the bluelab gaurdian since it will make my recirc setup very convenient. Would you say the gaurdian is as reliable as the others youve mentioned? Possible downside is that it sits in nutes 24/7 rather than storage fluid

Just bought a bluelab guardian yesterday with all the 420 sales going on I couldn't resist. Plus I noticed the price is going up on some sites. Cheapest place I found it in Canada https://indoorfarmer.ca/products/bluelab-guardian-monitor?_pos=13&_sid=636432100&_ss=r

rkymtnman said:

what ratios are you running your micro/grow/bloom at?

and i'm assuming you mix your cal/mg first and then micro 2nd?

Click to expand...

Yes, calmag, then micro, then grow, then bloom, then ph, let sit for a while, then hydrogaurd.

First couple weeks i was running 1:1:1 grow bloom micro, last couple weeks ive been creeping up grow and down bloom

MustGro said:

Just bought a bluelab guardian yesterday with all the 420 sales going on I couldn't resist. Plus I noticed the price is going up on some sites. Cheapest place I found it in Canada https://indoorfarmer.ca/products/bluelab-guardian-monitor?_pos=13&_sid=636432100&_ss=r

Click to expand...

Ah shit! Didnt realize they did 420 sales. Was it just one day, or anybody still have deals?

DWCgrower406 said:

Ah shit! Didnt realize they did 420 sales. Was it just one day, or anybody still have deals?

Click to expand...

Yeah lots of sites have a 420 week. Indoor Growing Canada does I think. Hlg.ca might too.

DWCgrower406 said:

Yes, calmag, then micro, then grow, then bloom, then ph, let sit for a while, then hydrogaurd.

First couple weeks i was running 1:1:1 grow bloom micro, last couple weeks ive been creeping up grow and down bloom

Click to expand...

maybe try Lucas formula instead. 5ml of micro/ 10ml of bloom , no cal/mg and you should be pretty close to 500ppms.

either that or use the 1;1:1 ratio to get 500ppms and then foliar spray with calimagice 1x or 2x a week.

and let your pH get down to 5.5 occasionally

DWCgrower406 said:

Agreed 100%, good grow starts with good instruments and ive been putting it off way too long. I think i have been at least very close since i calibrate with 6.86 at least weekly, but it could still be off slightly without the 4.0.
Plan was to get the bluelab gaurdian since it will make my recirc setup very convenient. Would you say the gaurdian is as reliable as the others youve mentioned? Possible downside is that it sits in nutes 24/7 rather than storage fluid

Click to expand...

The BL guardian is fantastic! If not for the price I'd have 1 for each of my 2 reservoirs. If funds allow they are pretty dam sweet. Half my hatred of ph adjusting or making a res is just monkeying with the instruments. To have a monitor staring at you from the wall displaying the vitals is as convenient as you can make the process. Even if I had to replace the ph probe every 6 months from sitting in solution constantly the convenience would be well worth the expense. I would have no reservations recommending the guardian. It will serve you well for many years.

rkymtnman said:

maybe try Lucas formula instead. 5ml of micro/ 10ml of bloom , no cal/mg and you should be pretty close to 500ppms.

either that or use the 1;1:1 ratio to get 500ppms and then foliar spray with calimagice 1x or 2x a week.

and let your pH get down to 5.5 occasionally
View attachment 4884086

Click to expand...

Sounds good, maybe ill try lucas for a while if i dont see improvement from recently adding more calmag.
If running 1:1:1 plus calmag, how much ppm of calmag is a good starting point? Also would you agree that im looking deficient in calcium and magnesium?

Oh, reread your post. So if 1:1:1, go with no calmag in res and just foliar? How strong do you mix for foliar?