DWC and PH 5.2, 5.5, 5.8 ??

After doing a bit of research I'm confused on the optimal PH for a DWC setup. To be sure, I've found charts that display the ideal PH ranges for various nutrients, but the overall best PH for hydro seems to vary by chart. There are two specifically, both of which can easily be found in an image search for 'hydroponic nutrient availability'. One indicates 5.8 as being optimal. One indicates 5.2-5.3 being optimal. In perusing various threads three numbers come up. 5.2 5.5 and 5.8 So I'm wondering to myself whether the basis for the discrepancy comes from a difference in setup during the tests behind these charts. For instance, perhaps one chart was formulated with DWC while another was formulated with ebb and flow. I've been using 5.5 but thought it would be worth asking what other DWCers thought about it, and if anyone could explain the discrepancies in the charts.

For hydro 5.8 is the sweet spot and 5.6-6.1 is the range.

What do you think about this chart? https://www.rollitup.org/attachments/hydroponics-aeroponics/1436982d1297522837-best-ph-hydro-ph-chart.jpg According to it 5.8 is the worst place for magnesium, and the manganese is dropping off pretty good at 5.8. 5.2 seems optimal.

I found another example on general hydroponics web site. The text states 5.8 is ideal but the chart clearly shows 5.2 being ideal. It also mimics the previous link showing various elements dropping off from 5 to 5.7/5.8 http://www.generalhydroponics.com/blog/2011/06/30/hydroponics-for-beginners-part-1-checking-ph/

Let your ph swing from 5.6 - 6.2 in hydro... run a little cal/mag if you need to. I have never heard of anyone aiming for 5.2 ph but give it a try if you think it's better.

Yeah, go ahead and try that 5.2, you dont need any advice from people that have done it for years.

No need to be sarcastic, I'm asking questions here and I did not state that "5.2 is better". The point of this post is to point out the discrepancy in charts and hopefully cone to some sort of conclusion on why the various charts have conflicting data. Here are images of the two conflicting charts. They are both fairly common. You can see that they don't contain the same data. Besides the question of PH is the issue of Phosphorus. In the first chart you can see Phosphorus has high availability at low PH and drops off as it goes up. In the 2nd chart It shows Phosphorus has high availability at high PH and drops off as it goes down. This is the exact opposite!

View attachment 2756361View attachment 2756362

So although I appreciate your advice, and have been sticking between 5.5 and 5.8 I'm curious if anyone can explain the differences in these two charts. Also if you or anyone has done comparative grows I would be interested in hearing about that and how it went.

That is confusing... I see the color chart all the time but I don't know the origins of either. Let the ph drift in a range around 5.8 so you get shit on the low end and stuff on the high end too.

Yeah can we get some more insight on this? I asked the same question in another post and got the same response. I was growing for 2 weeks at 5.2-5.4 and my plants were doing great. I switched to 5.6-5.8 a few days ago to see what's up but saw no visible change in my plants. Does the ph depend on the brand of nutrients? Why do people say 5.2 is so bad ? - i was doing fine at that level and am doing fine now.

^no visible change as in the plants continued to thrive as expected.

^ maybe your meter is off, when it says 5.2 you were actually at 5.6 and so now when it says 5.6 you're actually closer to 6.0, 5.6 and 6.0 being in the acceptable hydro range.

If that's not the case and your pH meter is fine, you can always try running at 5.2 for a while. You'll find out why people say what they say.

Right. I was running at 5.2 for 2 weeks. So then if I'm in flowering versus early veg would this be where I see problems?

superstoner1 said:

Yeah, go ahead and try that 5.2, you dont need any advice from people that have done it for years.

Click to expand...

So funny!!

But honestly...5.2 will not work.
You really wanna be 5.5-5.8.
A little high for a bit is ok, but much lower than 5.2 and your roots start to nub up and quit working...
Then the nutrient lockout kicks in and its pretty much game over.

A simple answer is human error. Plants can't read charts anyways so throw hem away and watch your plants...they will tell you what they want.

Lucas formula in R/O (8ppm) water gave me a pH of 5.2. I let it swing all the way up to 6.3
before add-back which took it back to 5.2. Don't look at pH with a singular number or idea.
pH should swing (within range) and indicates the rate at which the plant wants to feed. Also,
adjusting nutrient levels to the very edge of tip burn will let you know what the optimum feed rate
is.

LivingCanvas said it pretty well. pH damage will rarely show if you maintain your reservoir changes. The best thing you can do for yourself is to take a step back and look at your process for which you change your reservoir. Take the steps and make then as easy as possible. Add long hoses with valves, sub pumps and etc. If you change your reservoir twice a week, you will never have to worry about pH.

However, one thing you can use pH for is nutrient deficiencies. If you recognize something like calmag, raise your pH with extra calmag in your reservoir and the damage will be controlled fast. Same goes with other nutrients, check out the chart.

Myself, I like to adjust to 5.5, because the ph tends to adjust itself up as the res change gets closer. If you start too high 5.8 & up, it will just mean more adjustments. My res even varies slightly throughout each day. A daily ph test never killed anyone. Broken turtles advise on the cal-mag does work well also. Peace & be kind.

I've had no problems with keeping it between 5.8 and 6.2. It depends on what the strain will tolerate. play with it and see what you like the only way to learn is practice practice practice.