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I just saw this on another site and since I hadn't heard this before, wanted to run it by some of you - whatcha think?
"There are a couple factors that cause your PH to drift. The most common is running the nute solution too strong or too weak. If it's too strong, your PH drops. If it's too weak the PH rises. You have to find the balance point."
While true most of the time, it is not true with everything. Many factors such as heat fluctuation, nutrient strength, nutrient type, plant size, water hardness, reservoir size, ambient light all affect pH levels. As far as the relationship between nutrient strength and pH, they are two different things that need to be independently monitored for best results.
Quote:
Originally Posted by deftdrummer
word, dont forget the bigger the plant the more water they drink so the p.h. changes at differant times i use n.f.t. tanks and i check p.h. morning and night and depending on how much water they drink the p.h. is differant each night
Wow, actually I've sort of seen the opposite....nute solution too strong....ph rises....nute burn....but that's just me... :wtf:
Im puzzled too weedhound - but I did just increase nute strength to 1250 ppm from 1000 ppm (in 4th week flowering) and my pH is dropping from 5.8 to 5.4 during the course of the day....I'm somewhat baffled. Plants look fine so I don't think it's too strong....guess I'll just keep an eye on it.
:jointsmile:
Sure doesn't sound too strong....somebody mentioned people who go up to 2000 ppm/ I never would.....that just sounds scary. I know X-C had some ph issues recently with ph dropping. All I can say is I've honestly not seen it get lower with too strong of a solution.....always higher. I was telling him I had read somewhere....sometime....an explanation for that but of course I was blazed at the time and can't remember what it was. I've really only had that issue once and couldn't tell you what it was due to....eventually the problem just stopped but honestly if anything my nutrient solution at that time was too low...I had to deal with a copper defeciency to deal with as well when I switched to bloom nutes.....did you switch over recently?
Also are your ppms going up or down after a day?
looks like they went up - 1325 ppm right now. When I started this fresh batch Monday night it was 1250 ppm - Whats that indicate?
That they have plenty of nutes and are drinking up more water than nutes.....that is normal and usually why they recommend topping off at 1/4 strength nute solutions and such....to help readjust the balance. Keep in mind though that your ppm number does not reflect percentages....ie...did they eat all the phosphorus and leave the potassium behind....only total ppms. Does that make sense?
When I had deficiencies after I switched to bloom nutes my ppms would drop....fairly dramatically about 200 a day....that's when I was informed by my hydro guy that my plants were....ahem...."pigs" and to definitely up the nutes.
The relationship of Ph and nutrients PPM is found in the chart in the FAQ section that shows the different nutrients available to the plant at different Ph levels.
As the plant ages every 7-10 day??s the cycle of life changes and the nutrient needs of the plant changes. This is more evident in Hydroponics then in dirt growing because hydroponics does not have the same buffers that soil has. Yes you can use special microbes and live bacteria in hydro but that is beyond the experience of most growers and can be a pain in the ass.
So as the plant matures the Ph will raise and fall with the cycle of life too as it seeks out different minerals for that cycle of life as well. Hydroponics requires you to be almost obsessive about watching the Ph range of your plants.
Ph is more of a balance act then your PPM is so I would worry more about Ph then PPM. The PPM will change with in 24 hours of feeding your plants due to the mineral they take out and others they leave and even a third that the plant produces and discards back into your water. This will also change your PPM level.
Just remember that the PPM is only accurate when you mix it. Once you give it to the plant it will change on you and you no longer know what minerals are present and what the plant has added.
This week's show is all about nutrients and last weeks was Ph and nutrients you may find some use full information there as well if you want to know more.
Hey Doco ,Quote:
Originally Posted by doco
W/H is right - evap. / transp. of water into air or h2o that plants have used faster than nute uptake will increse ppm . numbers . I top off my res . w/ just un p/h'd r/o water when needed and this ups my ph bk. where it belongs w/o so much up / dwn chems and it brings ppm bk down . I still havta p/h the whole res 1 -2 times a day tho because ph is still dropping here ?
I have found the higher the ppm is the more stable my ph is tho. I think it's because theres more buffers in the mix w/ higher nute concentrations .
If ppm has dropped considerably between the 7-10 lapse of res changes I give em some more nutes mixed in w/ r/o when topping off the res.
Peace
Crispi :jointsmile:
I'm a newb still but I definately notice if the ph is higher like closer to 6 the plants can take a higher ppm of food but at around 5.2 I've noticed that the ppm tolerance is much lower although even at a bit lower ppm they seem to grow better
during a res change you have to compare the ppm before you replace with the new water any difference between those will cause a drift depending on how different the ppm
I have topped 1 footers in first day of 12/12 and I started them at just 500ppm maxibloom with ph at 5.2ish and last time I was at 800ppm to make them happy with 5.8ish ph
I just try to pay attention the first day of a res change and after that ya kinda know which direction and rate it's headin...but I do think there is some subtle connection between the life cycle and the excretion of the plant that causes ph to change I'd say if yer havin issues with ph travel put it to 5.5 and you have 1/2 a point to wander before it's any real issue on both sides ;-)
ASD I love you man.....you slay me with the ph talk.....:thumbsup:
Thanks for all the comments boys & girls. It was at 5.4 again tonight and when I left this morning I had it at 5.7 so it is still falling regularly.
I did a websearch and found falling pH associated with root decay so I lifted my buckets and the roots all look healthy as far as I could tell in the yellow HPS light anyway. My res temps are a bit higher than optimal but not by much - 73 at the moment but lights just came on - it'll get to 75 or so. I know that is starting to push the envelope. Does anyone here use a chiller with just a small waterfarm res? I mean its only 12 gallons....sheesh.
I tossed in 30ml more Hydroguard just for good measure and I may look at what dosage levels I should use H202 at, which I have never used before. If anyone uses it, gimme a shout.
Now I know how we scared Stinky off hydro LOL!!!
Hey Doco I use it sometimes....I was using a teaspoon a gallon for algae control and when that didn't work i was told to double it so now I use 20mls for 2/1/2 gallons....we are talking the store bought 3% here....every other day. I've sort of gotten away from it because I was using the cannazym and you can't use both but I've been using it in the veg stage of my grow this round at that dose.
Hi I was reading in the FAQ that wen your ppm is down you use a base npk to top of you water ! there is a math formula at : Text
I was just wondering if you use this formula ?
And how this precise ??nutrients monitoring? will effect our plant`s /yield at final harvest ?
I know it`s important to have a stable ppm but how important is it to have a correct does of N,P OR K ? (example : 1 tbs of N 2 tds of p 5 tbs of k = xxx ppm to top off water )
I have not hade the money to get a tds/ec metter to read my ppm I have just folioing G.H feeding chart and top off whit just water no new food on a daily base
I use 50% (horticultural grade) H2O2 at 1ml/litre every 3-4 days as an antimicrobial. Plants will tolerate 10x that concentration with no ill effect.Quote:
Originally Posted by doco
If you have an acute pathogen problem in a tank, do a one time dose at 5ml/litre then return to 1ml/L per 3-4 days.
Pharmacy grades at 3% & 6% can also be used, but it gets expensive if your tanks are large. Apply 3% @ 17ml/L and 6% at 8ml/L.
H2O2 can't be used with organics; it will break them down on contact.
Wow....impressive to whip those dosages off. I will take issue with your last line though....i use Botanicare and was told to use H202 along with it and have never had a problem and never had any sort of problem using them together. Anything along the line of cannazym or something however....no h202. ;)
Thanks WH, this stuff just accumulates in my brain. ;)
If the maker of something says it's OK with H2O2, coolio. However, you can do your own compatibility test in a teacup. A little water, some of the material you want to test and some H2O2. If the mix foams or bubbles when you add H2O2, chances are there's organic materials in the material you're testing and H2O2 is breaking them down.
Unfortunately, it's not possible to tell how much of a given nutrient exists in a solution with the usual nute meters (and yes, a nute meter is a necessary item in a hydro grow).Quote:
Originally Posted by stoneinks
TDS meters do just that- they display total dissolved solids (salts) concentration information. They cannot tell you how much individual N, P or K is in your nutes.
You're smarter to simply mix whole tanks per the nutrient maker's instruction and dump/clean your tanks every 2 weeks (or whatever interval your nute maker specifies), adding only plain water as needed between dumps. Don't add more nutes between tank dumps.
If a 2-week dump interval is specified, the chemistry has been engineered so there is a sufficient amount of N, P, K and other nutes for that 2-week tank life and they are present in the correct ratios to one another. If you add nutes in the middle of the tank life, you're very likely to alter the N:P:K ratio to something the maker didn't intend- and your ppm meter can't tell you if there's a problem.
Trying to jockey the nute strength to the same ppm on a daily basis invites nute burns. Resist the urge to fiddle.
You Go Al!!! I like it!!!!:thumbsup:
Awesome info everyone, thanks! Picked up some 3% h202 today as a stop gap measure and my hydro store carries 35% so I'll get that on Monday.
I may end up getting a small chiller if I end up staying with hydro (need a successful harvest first before I make the determination!) as I live in southern cali and summertime growing is calling my name despite the potential heat problems.
Chillers? Air conditioners for my beach apartment? sheesh!!! Will this madness never end?
Hey there doco and everybody,check this site out they have this chiller that is use in fish tanks.Its'called the ice probe at coolworksinc.com they have two models and a temp controler that turns it on and off.You just drill a hole in the tank and slip it in and tied the nut with a little silclone.I'am going to order one in a week when I have some extra cash. PEACE