Need help to use PH meter

[stinkyattic]

Rrog you are pretty much answering your own question- yes, there are wildly varied tap waters, and different feeding schedules listed for nutes. Yes, nute solutions contain Mg and Ca, but the LEVELS may be insufficient. It depends what the manufacturer assumes to be a good 'average' tap water mineral content that they are trying to complement with a formulation, and you will see that yes, there are actually 'hard water formula' nutes. There's no 'soft water' nutes; it is simply assumed that anyone running with very soft water from any source will use enough calmag to raise their background EC to the point where commercial nutrient formulations will work correctly on top of it.
Hope that helps.

 

[rrog]

Thanks attic. Well thats where I was going. If there's a hard water formulation, I presumed the other must be soft water. You're saying that's not the case and they likely all assume some background of CA and MG.

So I really need to find out what my base levels of CA and MG need to be and calculate if that's what's being supplied, especially given the 1/2 strength nutes I'm running.

 

[stinkyattic]

EXACTLY!
They assume a background level. If you run a soft water of any sort, your background falls well below what they assume it to be. Therefore, you must return the minerals up to that point where the manufacturers assume tap water to fall on average.

Just take your water in to the hydro shop and have them stick an ec meter in it. If it comes up quite soft, you should BUY an EC meter and calmag, and start running by numbers. I've had to do this on tap (well) water before and it's WELL worth the $100 or so that a Truncheon costs (best freaking EC device ever, omg, I love that thing!).

 

[rrog]

Well, I use RO water that was first run through a softener. So there's no Ca or MG. I have an EC meter to measure TDS, but no reason to even try it on the basic water.

Just curious if there's a listing somewhere of target CA and MG levels OR if there's a prescribed amount of CalMag to add to an RO nute solution?

You've been very helpful and thank you

 

[stinkyattic]

Oh hey hang on one sec.
You run a SOFTENER first, and then REVERSE OSMOSIS? Okay. That's fine, but if you are just running the softener you realize that that process is no more than ion exchange, and residual ions left behind in softened water intended for drinking and household use are harmful to plants? Usually it's potassium permanganate or a sodium brine of some sort, I can't remember, but unless you THEN RO the stuff, it can actually harm your plants very badly with sodium tox.

Your target levels should be around 250ppm of minerals; this assumes that the minerals are primarily Ca and Mg. So if your well water (as an example) comes up at 75ppm, you would then add calmag until the EC meter reads 250 ppm. That creates your background.

No problem, I have lost a large crop to fucking around with soft tap water and would hate to see it happen to others. It SUCKS.

 

[rrog]

Softener, then RO to filter out NA and CL and whatever remains.

My TDS is 400 on nutes, but you're saying CalMag my original RO up to 250 first, then add nutes and go like hell.

 

[stinkyattic]

right right. then pH as last step.

 

[rrog]

looked at the specs for Dutch Nutrient Formula and they state they say "Based on H2O with an average EC of 300-400."

So I'm CA+ MG+ deficient, no question. CalMag here I come.

 

[1984]

Oh shhh. That stuff is over my head guys. At the moment anyway. Can hyou help me out with this:

As if I didn't have enough to deal with, getting my head around water mixes, now I find I've got pH 8.3 but I'm not sure I did that reading correctly so I'm going to have to do it again. Trouble is it looks like ( so the groshop says) I have a nitrogen overdose on a couple of plants so I'm going to have to flush too.

Advice given was to mix 1/4 48 hour air exposed Tap water + 3/4 DW and check that the pH is low. Trouble is I am told that local water is high in calcium. I have DW at pH 5. But adding TW will presumably send that up. Anyway I have to get it real low and then flush twice the size of the pot (5L, so use 10L). I should then check the run off to see what it is...and if still high, do the same DW + TP mix, add some lemon juice (just for now as an emergency measure) and water.

So to the question: Would you say this procedure appropriate ? If not I'm betting and hoping you'll correct it.

Another problem is I've got a mite problem, so they say anyway but I'm not sure, it might be aphids, hard to tell the difference. I was given a liquid to spray which contains Dicofol and I can use it up to 2 weeks into 12h light period - now into 3 days. I've completely doused 2 of them. It advises not to use more than once so I'm praying it works. I noticed while spraying that certain parts of leaves kind of frothed white...isn't that the effect made by aphids? Question: will the Dicotol take care of the aphids if that's what they actually are - or will I need an alternative strategy?

I had left off using the ventilator for a few days after I had left it on all day by mistake - the girls nearest the fan looked shaken. I think that leaving it off so long was a mistake. I have 8 plants crowding a 400 hps and think there might have not been enough air circulation. Also the girls are very leafy, the fan leaves are large and don't allow much light underneath, so I was thinking of stripping back some of those fan leaves - in fact I already tentatively culled one or off 3 of them. If these 8 survive I'm going to cut back to 6 in the same space. (I have some 12 5 day old cuttings which are not wilting (!), they look pretty good - fingers crossed -). So do you think it'd be OK to cut back on some leaves, such as leaves affected by mite eggs, weak underleaves, and so on?

I still need to work out how to do the pH thing, measure it following correct procedures and then act on it...I need to get to work early too, nite guys.

 

[Rifman]

looked at the specs for Dutch Nutrient Formula and they state they say "Based on H2O with an average EC of 300-400."

So I'm CA+ MG+ deficient, no question. CalMag here I come.

low ph causes the plant to lock out calsium from the plant. calsium is in turn vital for the plants ability to absorb magnesium. im no botanist, so feel free to doublecheck this.

in any case, DO NOT OVERNUTE WITH CALMAG!!!

first of all, toss the fucking ph-pen in the garbage bin, light the garbage bin on fire and sink it in the ocean.

PH-pens SUCK!! you have to calibrate them so often that you will definately have ph issues. toss it, just bin it right now and go get yourself a "drop tester". you know one of those small bottles with consentrated liquid that you mix in little droplets with your feeding solution. usually 7drops of consentrated ph test to 5ml of feeding solution.

they will have this type of ph-test at your local zoo-shop, aquarium shop, pet store or whatever you call it locally. wherever they sell aquariums, buy the same ph tester they use on them!

srsly stop fucking around with electric ph meters, they are shit! SHITSHITSHIT! been there done that moved on... drop tests!!! and careful about giving calmag additives now. your plants should not need that until mid-flowering.

one more thing. if you are giving your plants normal full nute solution, it has everything your plant needs. if the plant is not looking healty, then you should look to other causes, like ph temps and such.

do not go out of your way to get expencive additives to your full nute solution unless you have full control of your grow.

in other words, if something is wrong, dont go adding more potential flaw factors to the image. stick to the basics. if the plants are dry, just water them, if you dont have DW.. leave the water you intend to use out for a few days. it will evaporate some of the bad stuff.

btw sry for my bad english, hope i was of any help.. and again, throw the ph-pen out the fucking window.. srsly!!

edit: btw when they speak of values in the range of 300-400, they are not talking about EC, but an other scale called ppm. read up on ppm contra EC values. there are several standards.

 

[rrog]

PPM would be what they are referring to. That's confusing on their part. PPM is derived from measuring EC. For full strength nutes the manufacturer recommends 300-400 PPM starting water. And I'm using 1/2 strength. So while the nute solution has CA and MG, it doesn't have nearly what the manufacturer recommends.

So I need to add.

I agree 100% about the pH pen. I still have mine, but upgraded to serious equipment with separate probes.