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Post by canuk1w1 on Dec 30, 2013 10:08:54 GMT -5
Today arrives the Zerowater filter and TDS meter. I have some stuffs lined up for re-potting some of my carnis and other plants (orchids and tropicals): Peat Moss - 3 types; - generic bulk bag, source Davenport Garden Centre - Schultz brand, source Plantworld - Alltreat brand, source Fiesta Gardens"Indoor" Sand - source, Plantworld - cheaper then the bonsai sand from Sheridan and the bagged "Horticultural" sand I've been using
Turface - source, Plantworld Schultz perlite - source, Plantworld Willgro medium charcoal - source, Plantworld APS (beige) - source, Menagerie Pet store Coir fibre - source, Menagerie Pet store Medium CHC - source, Menagerie Pet store Coir fibre - source, Grow it All LECA - source, Grow it All (there may be other stuffs kicking around I add to the list) I'm still working on the method but I think I'll do an initial soak in tap water. I'll baseline using Fernbrook distilled water. I'll use equal volumes of media in cut distilled water bottles. 1. Initial tap water rinse, 30 minutes soak, drain then take TDS reading. 2. Soak media in distilled water (min 12 hours), drain and take TDS reading. 3. Repeat step #2
Since I don't return to work until next week I should be able to get some decent data. Also looking forward to getting some supplies at the SOOS show. Comments/critiques/suggest welcome. I might even get another orchid while waiting for that box to arrive .
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Post by shoggoths on Dec 30, 2013 15:45:18 GMT -5
Hi G, I'm interested by Schultz peatmoss result. This peatmoss is really fine but I had lot of algae and mold problem with it. Also, for reference, test the content of all your water types before and after rinse. Have a good week
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Post by canuk1w1 on Dec 30, 2013 18:23:27 GMT -5
Merci Martin. Tap water is coming off at 148/149. Distilled water baselined at 0 as expected - both in glass, I will do the PET container as well. Results from the first rinse won't be ready until after midnight...
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Post by lloyd on Dec 30, 2013 20:41:15 GMT -5
Do you mean you are using tap water to rinse the media and measuring the TDS of the rinse (tap) water and then using the very same sample you just rinsed with tap water and then rinsing that with distilled water and then measuring the TDS of the second rinse? Or that you are using two different samples of medium and testing them. The first way would mean that the second measurement would be contaminated by tap water. I think that accuracy would require you to only measure the TDS of the distilled water rinse done on fresh media. Also not all TDS is bad. If you take distilled water, wet peat with it and measure the TDS of the water you squeeze out of the wetted peat, it will be greater than zero but will have almost no inorganic salts (NaCl, carbonates, etc. which are bad for sensitive plants like CP's). I realize the above seems needlessly complicated
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Post by canuk1w1 on Dec 31, 2013 16:40:44 GMT -5
G'day Doctor! Not complicated at all, we'd just like to ensure observational validity. BTW, what are your limits for using media again? Grow it All have some pricey water testers but these may give a more accurate count for dissolved inorganic salts. Some of them measure pH as well.
I rinsed the media in RO water (tested at 0.00). I discard that water then rinse again using fresh water. I do not use tap water at all.
Shoggs, the Schultz tested at 858 - I started soaking it around noon. It is finer than the others and darker in color, even when dry. It absorbs water much faster, it is thoroughly wet whereas the others (Alltreat and generic) are still mostly dry on top and I will need to stir them to wet them completely.
By comparison, some coir I bought at menagerie and have had soaking since Sunday with 2 or 3 rinses is testing at 793.
I'll get the rest started tonight/tomorrow.
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Post by lloyd on Dec 31, 2013 18:03:11 GMT -5
Schultz tested at 858-Is this the peat? It's insanely high, must have fertilizer in it. Fatal to CP's.
The Coir @ 793 sounds about right. It will need a lot of rinsing. You can rinse with tap water until the TDS reaches around 150 and then switch to distilled to save money.
Don't bother with expensive TDS meters. The cheap ones give a good enough idea.
I would hesitate to use water with TDS > 50 for CP's or >20 for sensitive ones or undrained pots.
I would use the same numbers for media (checking the rinse water).
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Post by canuk1w1 on Dec 31, 2013 18:34:21 GMT -5
Thanks for the numbers Lloyd. So much for Toronto tap water...
Yes, that is the number for the Schultz peat moss. I squeezed it through jcloth, so perhaps something may have contaminated it - I forgot to baseline water squeezed through the cloth. Makes sense to use tap water too, until the numbers get lower as you say.
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Post by canuk1w1 on Jan 2, 2014 20:28:45 GMT -5
G'day. Observations so far: 31DEC2013 - Schultz tests at 858 01JAN2014Indoor sand tests at 154 (caveat, a small sample after rinsing out fines, no agitation) Turface tests at 440 (after a thorough rinse a small sample of about 1 cup tested at 160) Coir tests at 375 02JAN2014- Schultz peat = 562
- Alltreat peat = 37
- Generic peat = 167
- Coir = 235
- Indoor sand = 185
- APS = 180
- Turface = 640
- LECA = 380
- Bonsai sand = 555 (this after a week of rinsing with water followed by a week rinsing in 5% acetic acid)
- LFS = 27 (one week re-hydrating in distilled water, one rinse in tap water, tested around 55 yesterday I think prior to final rinse in RO)
Martin, I'll take measurements for the peat tonight. FWIW, the Alltreat is almost fully wet but the generic moss is still completely dry for at least the first inch. I'll have to stir them up before I squeeze some water out. The initial peat results suggest it as the culprit for my early sundew mortality. Fortunately I've been top watering everything except my pings. I may get a peck of generic from Home Hardware or Grow it All tomorrow and test that, I need a whack of peat moss to re-pot my existing dews so I can switch to tray watering. Lloyd, the Coir numbers dropped as expected. One more tap water rinse then RO. I think it's almost clean enough to use for a tropical plant. BTW, was speaking with a mate about buying some surplus some surplus equipment and one of those fancy testers is included ;-) Have to get more details this weekend but there's some nice lights too. Looks like I'll be relegating the bonsai sand to top-dressing for my tropicals. No idea what the mesh size for Plantworld's "indoor sand" but based on the rinse results it seems a good choice. FWIW, I had to pan some organic material and APS from the indoor sand yesterday and it seems on the coarse side. Turface numbers are a big surprise. Obviously salts have seeped out since the initial rinse. Prolonged soaking is required. I'll be changing the water tonight for all the inorganic media.
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Post by LucST on Jan 2, 2014 20:43:12 GMT -5
You'll remove more salts and what not by soaking with distilled water due to osmosis, especially if you are using tap water with TDS ~150 ppm in it. Also it is pointless to compare the LFS to the other soils since it was soaked in distilled water, had you kept the same standards across the board then the results would be comparable.
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Post by lloyd on Jan 2, 2014 21:13:37 GMT -5
In order not to compare apples with oranges and to give the most useful numbers to everyone, I would suggest (IMHO) taking new media ingredients and hydrating/mixing them with TDS=0 water and then giving us those numbers. Successive rinse numbers and results would also be interesting: this would show if some materials can be remediated for safe use.
Using tap water to rinse & measure really complicates things and makes the numbers difficult to use-especially since everybody's tap water is likely to be quite different.
Making things more complicated is that some organic materials may bind solutes and thus the rinse water might have lower TDS than the tap water you rinse with. Some materials (such as a stone-like orange composite that I once used) might have low TDS rinse numbers but then leach out solutes over time and damage plants.
Organic materials (if not contaminated with fertilizer, like Schultze's Peat) will give a low to intermediate TDS but this will be due to organic salts which are not harmful to CP's and would be naturally in the soil/water where they are found growing.
I have tested Lowe's Silica Sand and it gave a TDS of 11 after a few rinses with distilled water, this reflects the silica content which would not be toxic.
I'd be interested in first (distilled water or equivalent) rinse numbers for Indoor sand, APS, Turface, LECA, Bonsai sand and anything else you want to check.
These numbers show how important to suspect any inorganic media component and any organic ones that are possibly contaminated. I would think that bulk peat/LFS/perlite/vermiculite/silica sand/clay balls would be safe to use without rinsing. Of course it can never hurt to check.
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Post by canuk1w1 on Jan 2, 2014 22:50:03 GMT -5
Agreed Luc, a full TDS=0 rinse would be best, but also expensive. With the Zerowater filter, that's now a viable option for me rather than $1.70/4L. In order not to compare apples with oranges and to give the most useful numbers to everyone, I would suggest (IMHO) taking new media ingredients and hydrating/mixing them with TDS=0 water and then giving us those numbers. Successive rinse numbers and results would also be interesting: this would show if some materials can be remediated for safe use. Using tap water to rinse & measure really complicates things and makes the numbers difficult to use-especially since everybody's tap water is likely to be quite different. Making things more complicated is that some organic materials may bind solutes and thus the rinse water might have lower TDS than the tap water you rinse with. Some materials (such as a stone-like orange composite that I once used) might have low TDS rinse numbers but then leach out solutes over time and damage plants. Organic materials (if not contaminated with fertilizer, like Schultze's Peat) will give a low to intermediate TDS but this will be due to organic salts which are not harmful to CP's and would be naturally in the soil/water where they are found growing. I have tested Lowe's Silica Sand and it gave a TDS of 11 after a few rinses with distilled water, this reflects the silica content which would not be toxic. I'd be interested in first (distilled water or equivalent) rinse numbers for Indoor sand, APS, Turface, LECA, Bonsai sand and anything else you want to check. These numbers show how important to suspect any inorganic media component and any organic ones that are possibly contaminated. I would think that bulk peat/LFS/perlite/vermiculite/silica sand/clay balls would be safe to use without rinsing. Of course it can never hurt to check. All true. I'll take some more readings on these samples but now I have some actual number and observations to work off and can do a better job preparing my media. Proper experiments would demand standardization of soak times, material volume/mass/surface area and solvent volume - all of which i try to keep approximately stable. Re: time-release - I'm hoping repeated readings from the turface give some hint of that. But as you point out, it could be adsorbing solutes gradually (and selectively) to a certain point then either release them in a flood or over time. Easy way is to assay a sample of the material at each TDS reading but I'm not even going to attempt that... Going forward, I'll do all rinsing with RO - and run some tests on snow melt to see if I can use it as sub for rainwater.
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Post by lloyd on Jan 3, 2014 16:36:04 GMT -5
Rain or snow falling directly into buckets is almost 0 TDS. Indirect collection can be higher.
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Post by canuk1w1 on Jan 3, 2014 18:55:59 GMT -5
That's what I figured. But catching snow direct is horribly inefficient! I tried scraping some (in the backyard) during the last bug dump but it didn't look too clean - probably grit from the shovel. I was fortunate to catch alot of rain and that kept me going for several months. I'm assuming no pint in taking snow from the front (contaminated with salt spray and dust) or after it's been sitting for too long. Next phase in pure water generation will be a reflux still and/or under-sink RO unit. I'm leaning towards the still as it'll be cheaper to assemble and I'll be independent (just need a heat source). With RO, I need to replace filters regularly.
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Post by lloyd on Jan 3, 2014 21:59:21 GMT -5
I tested snow scraped from the ground and it tends to be contaminated even if you try to scrape the top layer of undisturbed snow away from salted areas.
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Post by sokkos on Jan 3, 2014 23:00:03 GMT -5
How about snow from the middle of an undisturbed lawn? That should be pretty much TDS=0 right?
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