pH indicator strips

[2 2 2]

Hello:

If I had a penny for every time I've time I've read 'went to check my pH, but my pH meter quit working' in a grow report or journal, I'd have about $1.20 by now.

I've weighed my options and am going to use pH indicator strips from here on out. (Maybe someday I'll pay for a quality, digital pH meter but that day is not today. Hope you understand.)

The indicator strips I have range from 5.5-8.0. I'll be aiming for 5.8 for some hempy girls.

My plan was to pH-test my tap water, add nutrients (GH 3-part), and pH-test again.

My question is: Can I eliminate one of the planned pH-tests? And if so, why?

 

[Emilya Green]

Hello:

If I had a penny for every time I've time I've read 'went to check my pH, but my pH meter quit working' in a grow report or journal, I'd have about $1.20 by now.

I've weighed my options and am going to use pH indicator strips from here on out. (Maybe someday I'll pay for a quality, digital pH meter but that day is not today. Hope you understand.)

The indicator strips I have range from 5.5-8.0. I'll be aiming for 5.8 for some hempy girls.

My plan was to pH-test my tap water, add nutrients (GH 3-part), and pH-test again.

My question is: Can I eliminate one of the planned pH-tests? And if so, why?

hi!
the strips should work fine for you, especially since you will be working near one of the ends of the scale... it should be easy to see when you are close.
regarding your multiple tests, skip the first one. There is no need to test the pH of your water before adding nutes. It makes no difference what the starting water's pH was. The only pH that matters is the pH that you set your hempy container to when you actually water, because the container and the medium and the rez will all assume the pH of the nute mix when you apply it... it has no choice. Stir up your mix really well and then check the pH. Apply it to your plants.

 

[TheFertilizer]

Hemp buckets look interesting but I always wondered how you know when you need to fill again, just by weight? What's the advantage over drain-to-waste?

I like the pH drops personally. Haven't used the strips but I've heard people say they're really inaccurate, and if it's just one test per strip I bet you're going to end up going through a few just to get the level right each solution.

 

[MickFoster]

I prefer the drops - four drops is all you need - a bottle lasts forever.

 

[Major PITA]

If the strips are anything like the ones used to test swimming pools, they are not as accurate as drops or a meter. they also don't last very long. The chemicals used on the strips seem to break down over time so if you keep them around, in a few months the readings aren't as legible or accurate. PH meters are cheap. I've had mine for about two years and I'm still waiting for the battery to die. Best $11 I've spent on grow accessories (and it came with free shipping and two calibration solutions for that price).

 

[TheFertilizer]

If the strips are anything like the ones used to test swimming pools, they are not as accurate as drops or a meter. they also don't last very long. The chemicals used on the strips seem to break down over time so if you keep them around, in a few months the readings aren't as legible or accurate. PH meters are cheap. I've had mine for about two years and I'm still waiting for the battery to die. Best $11 I've spent on grow accessories (and it came with free shipping and two calibration solutions for that price).

That's a good deal. I was thinking about switching to electronic on my next grow. Constantly mixing and sampling with the drops gets frustrating. I assume with a meter you can just leave the meter suspended in your solution and add base or acid until the level reads right. Or do they take a minute?

 

[flexy123]

I use the drops and consider them very easy and accurate. I got a "cheapy ph pen" from ebay, that yellow standard model you can get everywhere...and I could make a better ph measurement calling Madame Cleo and just have her give me a random number over the phone.
However I am wondering whether strips would be better, especially if a solution has a slight color? How are the strips compared to the drops?
(I also see it as a problem that for using a pen, a good amount of solution would need to be in a cup or something....with the drops I only need a few drops in the test tube)

 

[flexy123]

Hemp buckets look interesting but I always wondered how you know when you need to fill again, just by weight? What's the advantage over drain-to-waste?

I am in the process of switching all my grows from organic soil to Hempies. Hempies are ULTRA-AWESOME imho, very flexible in what substrate you want to use, what pots to use etc. and just incredible simple.

I made two test hempies (3:1 perlite/vermiculite) like the classic Hempies but the next will be with an external reservoir outside (eg. bucket in a bucket) using AIR POTS. This would combine Hempies (Hydro) with the advantage of air-pruning.

I guess the reservoir, whether it be inside at the bottom or in a second container outside has the advantage that it provides a little like a DWC that the roots are actually *in* the nutrient solution.

** Before I choose to go with Hempies I did a lot of research into actual Hydro systems - first the "Wilma" system and then, what is IMHO the best, the Dutch (Bato) bucket system which is basically automated Hempies.

Problem with all those systems: They have 85-125L tanks which need to be filled and then changed every week. For me this would be MUCH more hassles than hand-watering, entirely negating any benefits. (It's not an "automated" system if I were to change a 125L rez every week or so...)
(Just the idea of emptying and changing a 125L tank in my green house on the balcony...I have no idea how I would do that "easily" since there is no proper drain and most importantly no water outlet. Would be a total PITA)

** As for watering...I am just going what some said....yeah by weight...pretty much as with soil
When I make the "bucket in a bucket/container" Hempies I will actually see how much they drink, this is one main reason I am trying this!

The external container is a simple food container, ca. 10cm or so high and with 2cm (1") or so space between the sides to fit the pots inside. Not too large. Simple as it can be.

 

[MickFoster]

Only problem with the drops would be if you're color blind.

 

[PurpleGunRack]

If your nutes add colour to your solution, the strips and drops will be even more inaccurate, also some nutes are made to be used with water of a certain pH range before mixing.

 

[Major PITA]

That's a good deal. I was thinking about switching to electronic on my next grow. Constantly mixing and sampling with the drops gets frustrating. I assume with a meter you can just leave the meter suspended in your solution and add base or acid until the level reads right. Or do they take a minute?

The cheap ones aren't meant to be left in the solution. They do take several seconds to read and they work best when stirred around.
I find them at least as accurate as drops and more accurate than strips. I verify with calibration solutions and only needed to adjust mine 0.1 over the last year. Drops use a little less solution to read but a pen only needs about 1/4 cup if you have it in a small container.

 

[2 2 2]

Thank you all for your replies.

I'll eliminate the first test. Thanks emilya.

I *loathe* cheap instrumentation with a *pink-and-purple passion.*

I don't think the color of the analysand impacts the color of a pH test-strip indicator. You can chemically test the pH of coffee, orange juice, blood--and these substances are not transparent. The solution being tested only needs to contact the paper briefly for the reaction to proceed, at which time you flip the solution off with a quick snap of the wrist; the color of the solution being tested is of no import because it's no longer there in sufficient quantity to mar the result. I have practically zero experience with the 'drop' pH test kits, so I'm not really qualified to comment on them. Sorry flexi123. (Although my hunch is that the drop kits are meant for transparent liquids only.)

Good digital pH testing equipment is expensive. There's no way around it. I wouldn't trust a two-cent thermometer to tell me if my infant has a fever. There are some folks out there who have, g*d bless 'em, figured out how to calibrate and store their pens in the proper solution and are having success with them. A far greater number have been foiled by these devices, because they're not dependable as sold. My preference is for repeatability and dependability at the expense of accuracy--until the day comes that I spring for a totally sexy digital model worth the name printed on the side of the box.

 

[PurpleGunRack]

The key to a precise meter is to calibrate often and store correctly, a $2000 meter drifts as fast as a $50 meter.

 

[2 2 2]

The key to a precise meter is to calibrate often and store correctly, a $2000 meter drifts as fast as a $50 meter.

I imagine that is so.

Do you know of any inexpensive digital pH meters that ship with the correct storage solution?

 

[PurpleGunRack]

I imagine that is so.

Do you know of any inexpensive digital pH meters that ship with the correct storage solution?

No, you might be able to find a kit, but it's probably easier to find a meter you like and then buy the buffer solutions and the storage solution, you can store in buffer solution pH 4.0

 

[Steveolevi]

I haven't used my pen since last grow 4months ago. I found some kind of mold or slime on my Apera PC 60 pen probe. Not much but something was growing inside the storage cap when out of use. I'm worried that even after cleaning that that meter will read incorrectly. How long (how many hours or grows) is recommended to replace probe?

 

[SmokingWings]

My question is: Can I eliminate one of the planned pH-tests? And if so, why?

The first one as @Emilya Green mentions.

I figure it is not a bad idea though to test the first one for several feedings just to find out what that number is. Most city tap water tends to be consistent but best to know.

 

[TorturedSoul]

How long (how many hours or grows) is recommended to replace probe?

That's sort of like asking how much a plant will yield, lol - it depends. I'm surprised the KCl or whatever storage solution Apera Instruments recommends for that meter's probe allowed any kind of biological life to grow, but then I'm also surprised that a rinsed probe had anything living on it in the first place. Weird.

You have cleaning and storage solutions, and pH 7 and 4 calibration solutions? I'd use the cleaning solution, then pretend it's a brand new device. In other words, if the owner's manual instructs you to soak/hydrate it for an hour in storage solution and then perform a two-point calibration using the calibration solutions that cover your expected working range (IOW, the 7.0 and 4.0 or 4.01 ones)... then do that. Then try checking the pH of multiple things that you know the pH of. If it doesn't appear to be accurate in its measurement, is slow to produce a stable reading, or is unable to maintain calibration for at least a week - it's time for a new probe.

I've owned several devices from multiple manufacturers over the years. With the usual cheap glass bulb type probe, it was not uncommon for the manufacturer to advise replacing the probe every six months. But it's merely a general recommendation; it's like telling you to replace your engine's oil every n miles - it really depends on the type of driving you do, and how you treat your vehicle.