New Primeagra question/problem

[Ross]

Originally Posted by Tindomul1of9

Ahh, good ol' lemon juice. Ofcourse! Thanks. And here I am trying to kill a fly with a shotgun.

Sure would have gotten rid of the salts though, you gotta admit

[xscd]

Originally Posted by Ray

Could be.

Steve, if you resoak those pellets, any chance of measuring the pH of the solution?

Hello Ray--

I found some old wide-range litmus paper in the house and tested it with vinegar (about 4-5 pH), baking soda with R/O water (about 8-8.5 pH), and baking powder (about 7.5-8 pH).

I then took one of the coarse PrimeAgra pellets that I used in the water-soluble mineral evaporation test mentioned elsewhere in this discussion, which had a visible crust of re-solidified mineral deposit, used a clean eyedropper to place a couple drops of rainwater on the deposit, let it sit for about 10 seconds, then dragged a fresh strip of the same litmus paper across the surface of the moistened PrimeAgra pellet. The pH appears to be about 5-6.5.

I'm doing another experiment now. I have a shallow dish in which I placed a couple layers of coarse PrimeAgra. I filled the dish with pure rainwater until the pellets were just covered (and a few floated of course). After 24 hours I'll empty the water and let the pellets dry, to observe whether and how much mineral solids will coat the dry PrimeAgra. Then I'll add fresh rainwater to cover the pellets, allow them to soak again for 24 hours, then empty the water and let the pellets dry again. I'll repeat this for at least 4 or 5 complete cycles to see how effectively the water-soluble minerals can be leached from the PrimeAgra.


Best wishes everyone,

Steve / xscd
New Mexico US

[20jlr]

Not sure but do you have to test the rainwater?
Or have you done it already. It seems to me you would also have to test the ph of the rainwater as a control.

[xscd]

Originally Posted by 20jlr

Not sure but do you have to test the rainwater?
Or have you done it already. It seems to me you would also have to test the ph of the rainwater as a control.

OK--valid point.

Using the same wide-range litmus paper I mentioned in a previous post, the rainwater measured slightly acid at about 6 - 6.5 pH, while reverse osmosis water measured between 6.5 and 7 pH.

Best wishes,

Steve / xscd

[IdahoOrchid]

Great discussion with lots of super thinking going on.

To my thinking, FRESH rainwater is a better description than PURE rainwater, though you could mean not mixed with other types of water or chemicals. Having evaporated through, then fallen through the sky and then across a metal roof, it is no surprise that the water tests slightly acidic.

What is the TDS of the rainwater as compared to the RO water as well. Between the PH and TDS you will be able to compare just how pure it really is compared to RO.

[Orchis]

Actually I'm not sure at all if it's reasonable to water Orchids with rain water, especially in places with
industry activities.
And it always important how you collect it.
At least with RO water you know what you have.

[IdahoOrchid]

Another good discussion on this subject over at this thread:

http://www.slippertalk.com/forum/showthread.php?t=2759

Ray, if you could review it and chime in it would be appreciated. I realize you cannot be everywhere, that is why I mention this specific thread.

[Ray]

Wow! I should add Slippertalk to my regular reading routine!

There are SO many different subjects in that thread, it's hard to address them all.

The new PrimeAgra wicks better than the old primarily due to the more regular surface, which creates better contact area.

The more uniform size and shape results in more air flow, so that does, indeed, result in greater evaporation. I do not water daily (especially this time of year), but my greenhouse humidity is pretty good, so the surface of the medium in my pots is likely to stay more moist, keeping the nutrients in solution where they can be absorbed by the plants, and making the mineral content less saturated.

The new PrimeAgra does NOT have more of a wet film at the surface than the old stuff. It's actually probably less the case, as the old stuff had some highly densified areas at the surface that could get wet and not absorb the water. The new stuff absorbs and releases much more thoroughly.

That difference in absorption/release properties may be contributing to the observed surface mineral buildup, as by contrast, more minerals were "trapped" in the old stuff, which I guess could lead to chemistry issues over time. The improved wicking can also contribute, as was noted in the thread. The initial free mineral content from the manufacturing process is also probably higher in the new material, but probably releases better. I still rinse the crap out of it before use - and always have.

I have mixed the old and the new, with no issues.

I've been using the new PrimeAgra for a couple of years now, and have not noticed a mortality rate any different than with the old. I believe I have, on the other hand noticed better growth and blooming, presumably due to better - and more stable - water and nutrient availability.

Some responses to sub-threads:

RO water SHOULD, if your system is working right, give you at-most single-digit dissolved solids. The capacity of the system is irrelevant, as the components are different to accommodate that.

TDS meters are notoriously inaccurate, as they are really just electrical conductivity (EC) meters that have a built-in conversion factor that displays the output in parts per million (ppm) of total dissolved solids (TDS). The trouble is that the relationship between the conductivity of a solution and its content varies not only by the concentration of the dissolved ions, but is also based upon the charge and mobility of the dissolved ionic species. That means that in our case, the "standard" conversion factor cannot be standard at all, and actually varies with the fertilizer and water supply. I have an article about that on my "Free Info" page.

Calculating the TDS of the MSU fertilizer in RO, at 150 ppm N, your meter should see something in the neighborhood of 425 ppm TDS. My two meters gave me about 600 and 750.

There's a LOT more to good culture than just the medium used, and one must observe and adjust accordingly as something changes. Even under the worst conditions, I have never heard of anyone killing an otherwise healthy plant in a week. I'd almost bet that submerging a pot in water for a week wouldn't have that quick of a kill.

I always respond to emails I get, assuming they have a subject line that is intelligible and pertinent, or from someone I know. Blake posted some pretty nasty commentary about me both at Orchidboard and Slippertalk, and I honestly do not recall getting any emails from him on the subject. Ignoring things like that is simply not my way. I'm truly sorry that the communication disconnect happened (and no doubt soured him on my apparent attitude), as I would have liked to investigate the situation with him, both to try to fix the problem and and to potentially learn more myself!

As someone stated, so far Blake has been the only one that has expressed problems with the new material, but do keep in mind that folks can express discontent not only with their mouths, but with their feet as well, and just not buy the stuff. Based upon the rate at which it is moving out of my warehouse and the emails I get on the subject, there does not appear to be a widespread problem.

[Orchis]

One thing I know for sure from experience:
if I soak and rinse pellets few times really well before, there couldn't be any noticeable salt buildup release of any minerals what ever...
There is so many factors influencing Orchid culture,
that it need a some amount of sensitivity and intelligence
to get success. We all grow Orchids but no one the same way...Orchid culture is creative process, an Art. IMO

[IdahoOrchid]

Originally Posted by Orchis

One thing I know for sure from experience:
if I soak and rinse pellets few times really well before, there couldn't be any noticeable salt buildup release of any minerals what ever...

That all depends on how well bound the minerals are to the remainder of the material. It could be so well bound that they could be released over MANY years no matter how many times or how well it is pre-rinced prior to use.

The key is, as I think you suggest, to adjust your culture to meet the current state of things. Of course using common sense prior to starting is a must.