Dr. Funkenstein

Ok, I've got a question or two.

I'm using a HANNA combo pen, and the damn thing is always off. I can calibrate it, and it will be off after one res check. When presenting this issue to the community, I am usually confronted with the usual replies. Some say their pen is screwy, some say they use soil so it doesn't need to be as accurate for their needs. Some say to settle for a few points off.

Well I am in hydro, so I'm going go out on a limb and assume the pH pen needs to be fairly accurate, within a few points of where it should be.

They say don't worry about it, read your plants. Which is almost easier than dealing with a bunk pH pen.

How do you manage your reservoirs? I can set the nutrient level begining of the week at 800ppm, and it may rise over the course of a week or so. Meaning the plants are using more water than nutes.

Should I be doing "daily" add backs to try to acheive equilibriam, as opposed to a bi-weekly add back to top off the res? If this is the case, I should be keeping R/O water on hand to keep this in check.

Also, if I'm seeing a deficiency in a plant, how do I take immediate action to provide the right diet for the plants without emptying the reservoir, say, just a day or so after doing a fresh change out? Surely, you're not suppose to leave the reservoir as is for a week or two, while the plants continue to take a beating at 6 feedings a day?

How can you ever be able to ballance things out, if you were forced to wait a week or two before you could effectively solve the problem?

Sorry if these are stupid questions. I'm almost done with construction and want to get a better handle on how to maintain my womens.

Thanks in advance.

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Dr. Funkenstein

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nilknarf420

Those are good questions.


I use a Hanna meter too. I bought the one that costs 170 dollars not at home so I am not sure the exact model. It is black though. I rarely need to calibrate it. It will stay within a few hundreths for a month at least.

The only time that you should worry about a complete reservoir change is if your nurtient solution is really old or badly fucked up.


We all struggle to maintain equilibrium in hydro. I have had quite a few small issues since switching to NFT.

The best advice that I can give is to shoot for a fairly steady EC/PPm and pH.

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CRAZYTRAIN

Agreed steadiness is worth shooting for.

Your questions aren't stupid at all. And I think I can share my experiences and shed some light. I can't answer all of them though.
I've gone through 4 hanna combo meters and 1 Milwakee meter in the last 2 years. The first few hanna meters I had worked great until they stopped working. The Milwakee meter lasted me about only 2 months. The last hanna meter i picked up was about a month ago and I had to take it in to the shop I got it from today because it was reading so crazy. I tried calibrating it this morning and when I put it in the ph7 calibration solution it read 2.9. The guys at the shop looked at it and I ended up walking out with a new probe.
I think the guy gave me the new probe because he sent 2 of my meters back to hanna over a month ago and hasn't heard diddly squat from them.
I don't know why your meter is acting up, but it may be bad, so what I would do is take it back and ask them to check it for you and hope it acts up while you are there so they can see it and help you out.

Now on topping your res----- I think the answer to your question lies in how fast your ppm climbes. if it's only climbing about 25ppms per day or less then I would probably top it about twice a week. If it's climbing over a 100 ppms a day then I'd definately top daily and I'd probably drop my ppms by a few hundred and see if I can get the plants eating as fast as they're drinking. When you get the ppms swinging down instead of up....that's a beautiful thing. Now these are my opionions.... other growers here may disagree.

About the defs------ Sometimes your plants can get defs from "lockouts" caused by your nute solution being to strong and one element locks another out from the plants. Other times your "lockouts" can come from your ph being too high or low. Then you can get "lockouts" from underfeeding. I haven't mastered yet how to identify each culprit of my lock outs but I'm getting better. You don't need to dump your res, you can adjust it.... And if you are getting a lockout you should be attentive to it right away.
If you are getting them from the ppms being too stong you will often notice really dark leaves or "eagle clawed" leaves or burning tips to go along with it. If you are getting them from the nutes being too weak you'll ofter get the bottom leaves paling to yellow. If it's a N def usually the whole leaf goes yellow.. If you are getting a mag def the leaves go yellow but from the tip of the leaf back and often the veins in the leaf stay green. Sometimes you can get a mag def from incorrect PH and sometimes its from too much Calcium in your water, which can lock out Magnesium.
SO adjust your res frequently, try to get it so the ppms are going down and the ph is swinging up. You should then watch the plants to see if they start getting defs. If they don't then ride that setting a little while. Let the ph swing from 5.5 to about 6.2, then keep lowering the ph so it stays in range. If you start getting defs and your res activity was ph swinging up and ppms dropping then you are likely underfeeding and can add nutes to the res tank to lower ph into range. You can try raising it about 50 ppm per feeding for a day, then reacessing and so on.
Again other growers may tell you to do otherwise, this is only my humble opinion.

Good luck with the ph meter

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sek311

Hey Doc,

I just purchased a Hanna combo pen and I'm getting pretty steady readings. I used to work in a research lab in college and I'm pretty much using Lab protocol like I do on all test equipment to this day. Here is what I learned from my professor years ago being his bitch in his lab.

First off I have 1 FL oz. sample containers which are basically those little plastic medicine cups. they're clean and don't cost much and they're nonconductive so they don't mess with values. I also have a gal bottle of distilled water in my test area. Next I also have a sampling container something big enough to get a good sample its also and easy to pour (mixing cup) and one marker. We used a three step process which was very simple.

my containers are marked as followed

Solution
Rinse/burn
control/store
PH Cal
PPM Cal
etc...

First I fill the containers Rinse/burn and Control/store with DS H2O. Zero your instrument in the control/store since you know distilled water is EC/PPM at ZERO make sure to shake off the control. Then grab a sample and pour it into Solution and take your reading. On my Hanna meter you wait until you see the little clock icon goes away and the immediate number is your value. If the value is to my liking then the next thing I do is pour a quick rinse from the gallon jug over the meter head and then I dip the head with a up and down motion in Rinse/burn in PPM mode. If the value isn't zero I burn the DS and refill it and check again. When it zeros I then dip the head in Control/store once again and check for zero and without shaking excess water I put the cap on and store upright. I then pour everything out and lay the cups upside down on a paper towel to dry.

All my calibration chemicals have a separate little cup to keep from cross contamination. It seems like a hassle at first but I learned long ago that a clean lab with procedure gives you results you can trust.

NewGrow19

sek311,

I am Impressed, that's some crazy talk, but it just might work
What do you use for rinse/burn? Distilled H2O?
Those 1 FL OZ cups are a Great Idea, I plan on implementing immediately.
Thanks for sharing

sek311

Distilled water on Rinse/burn your cleaning step I just pick up a gal of DS water from the CVS by my casa. Thats where I got the little cups from too. In the lab we had a DS tap labeled "DO NOT DRINK" at every station. Distilled H20 is a universal solvent. I think Distilled water was a health fad for awhile for rich nutty women but it leaches minerals from your body fluids??. =P good luck!

g1ithc

(says the broken record--)
Go with liquid pH drops by GH, they won't ever become "uncalibrated" and are very accurate unless you are color blind. It will end up being a lot cheaper since you don't have to replace probes, but rather inexpensive liquid. (Its 7 dollars for a 8oz bottle, which will last a very long time). You can buy the pH testing kit first just so you have a squeeze bottle and plastic vial. Sure you won't know the pH down to the second decimal, but you can have an idea if its 6.0 or 6.1. I've been raised with electronics my entire life, and therefor realize their insanities, Liquid pH drops for me thankyou

the ppm pen however, i use a hanna primo which is $20 and have had it for a few years and hasn't steered me wrong, you only need to calibrate it once, and they can't dry out, no replacing probes etc, well worth the $20 investment

as far as setting ppm and pH, I always set it at 5.5 pH, and make sure they are eating slightly faster than drinking, so the pH rises and the ppm drops. When it hits 6.1, and the ppm is significantly lower, i usually just top off with more nutrients and set it back to 5.5, let it do it again, then res change (but I realize that throws off the NPK ratio a bit)- humidity plays an important role

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SweaterVest

I love this site, this was just the fourm i was looking for, Because hempy doesn't have a resivour like you would think in a active Hydro system there wasn't really a fourm like this for hempys (not that i could find) so now i know what to buy tuesday

A PPM/EC meter
Ph drops

THanks GC

M_Jacobs

Sek311: has the right idea. Keeping things, clean, organized and documented! After awhile you will get lazy and start skipping things here and there. But try to keep up with being clean and organized. It will PAY off in MANY WAYS!

My biggest TIP: WRITE DOWN YOUR MIXES. WRITE DOWN EVERYTHING!!!
Basically I can tell right away when something is wrong because something isn't following the correct pattern/history. For example if I make a fresh res, and follow the exact formula I always follow and the PPM and or PH is off I usually recalibrate both meters and things are back to normal. Or if i'm doing my weekly RES check, and the numbers aren't where they should be, I can usually prevent any DEF before they appear.

Also a bigger RES helps keep things a little more stable. I started with 35Gal RES for my trays and by chance I had a 45 Gal res for my 2nd tray. The 45 was soo much less hassle in terms of PH and PPM flucations I changed all my RES(s) to the 45.

Here is my schedule:
Week1
Fresh mix. 45 gals, 1250ppm TDS at 5.6PH
(6gals of RO water is added every Mon, Wed, Fri.)
Week2
Mix should be at 1050ppm TDS (-+30ppm) and 6.2PH (-+.05PH)
Top off to 1250PPM and 5.6PH
(6gals of RO water is added every Mon, Wed, Fri.)
Week3
Mix should be at 1095ppm TDS (-+42ppm) and 6.0PH (-+.15PH) [can't figure out why
the difference in numbers. from Week 2 but I just go with it]
Don't top off. Adjust PH to 5.6PH only.
(6gals of RO water is added every Mon, Wed, Fri.)
At the end of Week 3 I dump the RES, and swap it with a clean RES so that the used one can be cleaned and sterilized.

OHHH forgot to mention. Don't go with the liquid PH test. Instead go with the PAPER test. Totally forgot to mention that. A few of my additives have a really strong coloring to them, so reading a liquid test is impossible.