HYDRO Dropping pH DWC

[NickyChicks]

I've been having some issues with pH fluctuations/dropping pH. I did a res change on Wednesday, Thursday pH was 5.9, Friday 5.5, today 4.9. PPM read 880 when I changed the water, today it's reading 1020. Water level is down about a gal maybe a little more. The strain is Blue Cookies Auto, GHTrio, armor Si, liquid Kool Bloom, Calimagic, Hydroguard, GH pH down and tap water.

Any DWC growers have issues like this before? I've read some info but I can't find anything definite or insightful enough, hoping someone can give me some guidance to resolving this. Any help is greatly appreciated!

[Tersky]

If your ppm's are going up and water level going you may be over feeding as it is drinking more than it's eating. Depending on the nute that is in excess it can cause ph drops or spikes. You may need to tweak your GHTrio ratios when adding Kool bloom as well (depending on the feed schedule you are using). I would take a look at the roots just to check as sometimes root issues cause plants to drink and not feed but more than likely its an excess in something.

I have also found that ph fluctuates sometimes when a type of growth happens especially during the ripening stage.

[NickyChicks]

I should add, roots looks great, I've been very vigilant about checking the roots as I had some issues at the start of the grow with water temp and root rot. I have since resolved that.

[Tersky]

i would use plain ph'd water and then test ppm, wait a day and check ppm again to see if it increases or decreases. Maybe it's just going through a spurt and the ph is dropping so its not able to uptake properly...i would do consistent res ph checks and maintenance making sure ph is in a good usable range and maybe it will grow out of it? If the plant looks healthy otherwise, it might just be a problem child so to speak.

[NickyChicks]

Added a gallon of water this morning, my water is about 7.65 out of the tap so I just added it as because I figured If I had 1.5-2gal of water with a pH below 5.0 it would equal out. About 12hrs later I'm sitting at 5.89 and ppm reading 883.
You mention possibility of a spurt of sorts, my northern lights had pH issues last week, this week it's stable but the amount of new roots that exploded from the side of the net pot over the last 2 weeks is pretty impressive. The blue cookies that this post is originally about is showing the same kind of brand new root growth not as the NL tho

[NickyChicks]

All those very white shorter roots are new on the NL in the first pic. The BC is the second pic, if you look close you can see some bright white roots within the net pot and some coming out of the side of the net pot

[alltatup]

Not sure if you've had this question about pH answered yet or not: I check the pH of my reservoir every morning, and I usually have to add some pH up after a res change for a couple of days before it stabilizes. If pH is low, I'll raise it to 6.4 and let it fall for a couple of days. I like to let the pH fluctuate, never have had a situation where it stayed the same all week. If my pH read 5.9, I'd raise it a bit, not allow it to keep dropping.

[alltatup]

NickyChicks I don't know about that. I don't think it matters how much pH up or down one adds in order to get the water to the correct pH; I've over-shot a few times and had to add the opposite liquid to correct my mistake. I mean, pH'd water is just pH'd water.

I don't know why pH fluctuates; it does so differently at different times in my grow, but with my nutes, I almost always have to add pH up. I've never read that pH should remain static, because different nutes absorb better at different pH levels. So it's good for it to fluctuate: that's what I read on GWE, and that has always been my guideline. And to tell the truth, I've never had a reason to check ppm, so until I do, I reckon I won't. But I'm religious about keeping my pH in line. ;-}

[NickyChicks]

I heard it from a GWE YouTube video thats linked onto the article about managing pH. It's an 8min long video but if you skip all the way to the end and play it at 6mins 55secs you'll hear what I heard. I messaged GH so I'll see what that say. Believe me, if it's cool to add both the the same res, I'm in. But I still believe there is something causing my drop in pH. I agree that pH needs to swing to allow nute intake at different levels but a drop like I'm having and the marks I was seeing on leaves indicated an issue.

[NickyChicks]

GH answered my question regarding using pH up and pH down. I asked.... "Hey is it ok to use pH up and pH down in the same DWC reservoir? I use pH down to get my pH level where it needs to be when I change the reservoir water, over a few days the pH will drop, is it ok to use pH up or is it better to change the reservoir water again?"

They confirmed there are no issues using both and that makes me feel much better. I have now been doing it this way for just over a week and no adverse effects.

[Obi-Wan]

In my opinion the Armor Si is briefly bumping up your pH during the initial mixing so your adding pH down to bring your solution back down to range. The problem starts when the pH rising effect of the Armor Si starts to subside, now you have too much pH down in the solution so your pH starts dropping quickly.

I’ve had this problem with both nutrient lines(GH and DynaGro) that call for silica supplements that I’ve used. What I did to remedy the situation was start mixing my nutrients a day ahead of time and only added pH down if the solution was still too far out of range after 24 hours. It isn’t uncommon for my DynaGro solutions to read 7.5 after mixing, 6.5 the next day, settle in around 5.7 on day 3 before starting it’s eventual rise back up.

[NickyChicks]

I just checked to verify an accurate measurement, 7.59, 359ppm from the tap. I use a water filter for my drinking water because I know my tap water, in my opinion, sucks. I don't have any sort of water report but I'm sure I could get one. Im under the impression it's the amount of chlorine in the water and it aerates causing an increase in pH. Therefore I need to offset with a larger amount of pH.

[Obi-Wan]

With your starting tap I’d mix just the GH trio with LKB and see if you can get it to stabilize. If it stabilizes add your Calimagic to the next change and see if it makes a difference but with your starting ppm from the tap I’m not sure you need Calimagic or Armor Si.

[NickyChicks]

I know I don't need armor si but it definitely has made a difference in the size of my stalks and strength of the branches. As for Cal-mag I had signs of Cal-Mag deficiency when the plants were very young and I wasn't using it in the nute mix yet, I have a ny diesel and bloody skunk that were started 2.5 weeks after these girls and I started them on Cal-Mag early and never saw any issues. Same thing with my first grow, I had Cal-Mag deficiency mostly in my chocolate kush plant but it was early on and once I started using Cal-Mag, no issues. When I started growing I didn't think I would need it either, especially given my starting ppm like you said.

[NickyChicks]

As i was looking for answers to my problems a few days ago, I stumbled across a post and a chart that RagWeedDWC shared. The chart seems helpful except I'm measuring ppm not ec and I'm not sure I'm converting correctly.

[Obi-Wan]

Divide your ppm by 500 for an accurate EC measurement.

[NickyChicks]

Ok that's what I was doing, well I was multiplying by 2 and divided by 1000 but same thing

[RagWeedDWC]

The rest of that post may help explain, but not sure if it matters on PPM or EC, if either is static or dropping is the concern. I have not fully vetted this chart, got it from another source, but I have used it, and it does seem to help narrow in the issues.

The ideal scenario you are looking to achieve is where the EC is either dropping slightly or remaining static, with a static or slightly rising ph and a dropping water level. If you get this situation, keep doing exactly what you are doing because your plant is feeding and drinking.

Note 2. Most people assume that with a rising EC, it is the plants way of saying, I dont want more food, here, have some back. What is actually happening is this. Plants roots take in water/nutrients through a process called Osmosis. Effectively, if you think in terms of the roots having their own internal EC. The osmosis process will always try to balance out the EC's, taking from the higher side of the barrier and giving to the lower part. So if the EC of the nutrient solution is higher than the "internal EC", then food & water will flow from the solution to the roots, this is the normal process. If however, the EC of the solution is higher than the "internal EC", then the balancing will work the other way and nutrition will be leeched from the roots to the solution. A res change or increase in EC should resolve depending on the other factors such as ph and water levels.

Note 3. Nutrients flow around a well hydrated plant much more effectively and faster than one which isnt as well hydrated. How can growers use this? By feeding at lower levels, the plant needs to take on more water in order to get the nutrition it requires. So by feeding at moderate levels, this forces the plant to drink more. By drinking more, it is better hydrated, because it is better hydrated, it needs more food, making it eat more. So feed at moderate levels rather than overly aggressive levels. The method of pushing the EC until you see signs of nute burn is damaging to the plants and although many growers use this method, I am not a fan though your plants are not mine!

[Tersky]

I have never heard of internal EC and can not find any research talking about it other than other weed posts (have not seen any scientists talking about internal EC). I still think if ppm is rising, water level falling then you are over feeding. It may be nitrogen if the plant in the pic is the one you are talking about as the leaves look dark green indicating nitrogen toxicity.

[Obi-Wan]

I like this chart except where they claim that the plants take in nutrients by osmosis at the roots. They absorb water by osmosis and the osmotic pressure they describe can reverse leading to the plant releasing water from the roots. Nutrients are taken in by the plant roots through a process called cation exchange that takes place independently from water uptake. If the roots are leaving nutrients behind in a DWC reservoir to the point where the solution EC/ppm is rising either the nutrients are locked out or the plant doesn’t need them. Nutrient uptake is like a toll booth on a one way street with carbohydrates being paid by the roots as the toll. Once the nutrient is in the plant the only way out is through consumption. Plant leaves can absorb nutrients into their cells through osmosis but their roots require a more selective process.

[RagWeedDWC]

I think the chart is a hand grenade range type thing, in my last grow I screwed up the cal-mag, it was causing all sorts of issues in the test plant. i adjusted nutrients without adjusting the cal mag, increasing the PPM but not really helping the matter.

[NickyChicks]

Tersky , you're right the plant does look dark but it is actually starting to look a little better. It was darker last week. I cut micro to half of what I was feeding them, I only did this on my 2 plants that are furthest along in flowering because they got to be pretty dark almost blue.

Obi-Wan you definitely have a better understanding than I do in how plants feed and drink. Thanks for dropping some knowledge

I really appreciate everyone's input. I think I can go about this a few ways to see what works,. I can increase the nutes for one plant, I can decrease the nutes on another, and I can leave another the same. I'll take readings morning and night to keep close track of what's happening.

[UndergroundFarmer]

I'm late to this party but yes, especially after I started air conditioning the basement the plants seem to be using much more water than nutes. I've been topping off with tap water which raises the pH. That's been fine because the pH has been dropping as the EC goes up.

[NickyChicks]

I've got an ac running and a dehumidifier. My window unit keeps the basement cool but it doesn't remove moisture for shit. I have a real nice dehumidifier that pulls a lot of moisture from the air and I keep it regulated between 45-50%, sometimes it gets a bit higher when I need to empty it and it shuts off