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03-04-2021, 09:45 AM
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Join Date: Mar 2010
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My tap water is PH 7.8 and TDS 267. I don't know what I would get with adding my tap to distilled. I would just have to do it and then measure. I liked Ray's advice about trying the k-lite fertilizer and not having to buy water. I was thinking more about this last night and wondered about when the low ph of 4.5 with dyna gro set in the pot and it raised the ph. If i add k-lite to my tap water and do the experiment again won't the ph be up to 8 or more?
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03-04-2021, 11:36 AM
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Quote:
Originally Posted by Shawna
My tap water is PH 7.8 and TDS 267. I don't know what I would get with adding my tap to distilled. I would just have to do it and then measure. I liked Ray's advice about trying the k-lite fertilizer and not having to buy water. I was thinking more about this last night and wondered about when the low ph of 4.5 with dyna gro set in the pot and it raised the ph. If i add k-lite to my tap water and do the experiment again won't the ph be up to 8 or more?
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As far as the resultant TDS is concerned, it would be a simple ratio - 50/50 would be 0+267/2=133 ppm.
If the pour-through test with the Dyna-Gro solution showed you a pH of 6.6, I wouldn't expect it to be too much different when using K-Lite or even distilled water, alone.
Once you mix tap water with purified water, all bets are off. The alkalinity of the water (resistance to pH change, not a high pH) is far more powerful than is the pH itself, so you'd have to do some testing.
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03-04-2021, 03:31 PM
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Water has a PH value, a TDS value or the total dissolved solids in the water, Alkalinity, Hardness and a temperature.
Most understand PH but the PH is not just a matter of having a value and increasing or decreasing it.
The alkalinity will play an important role in determining what PH the water ultimately will be.
As to the run off test, well, lecca is inert so any buffering it does short term is not really a great test for lecca imo, it's short term, long term it will be the water we run through it that will affect it since it is completely inert and shouldn't have an effect on water long term (short term it will)
So in my opinion I would advise you do pay attention to the water going in, more than the water coming out.
Now on to alkalinity. This determines how stable a ph level will be. Imagine Alkalinity is a sponge, an invisible sponge that all water has (obviously water has no sponge this is just a visual example to explain alkalinity)
If the water has a large sponge it will be able to absorb any chemicals trying to alter its PH and you will need to add more ph adjusters to saturate the sponge and make a difference to the PH.
RO water has practically no sponge or no buffering capacity or a low alkalinity so adding any ph altering chemicals will have a drastic efffect compared to tap water with a higher alkalinity and more resistance to change.
As such any fertilizer added to RO water will have more of an effect than on tap water as their alkalinity is different.
Some fertilizers have ph adjusters added to them that in theory buffer tap water to the correct level.
But as you have noticed if you use these chemicals on water with a very low alkalinity these chemicals can overshoot the target and make the water too acidic. PH-up adjusters can be bought to easily fix this.
Hardness is a measure of the calcium deposits in the water - how much limescale will build up in a kettle basically.
Temperature should be not too cold as orchids do not like the cold.
Hope that helps.
PS: Ray did not mean you can stop paying for water lol, all he meant was that other fertilizers are watered down compared to K-lite so you are "paying" for added water in the fert bottle.
I also agree to aim for 100-150ppm for total TDS.
Try mixing the water, see what it does, 10% tap water is a good practice anyway as tap water contains a lot of calcium so 10% of tap water covers the plants needs and should increase alkalinity
Last edited by Orchidtinkerer; 03-04-2021 at 03:52 PM..
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03-05-2021, 09:47 AM
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Orchid whisperer,
your articles just confirm what Ray has said...
I mean look at the graph from your first article. Cut leaf tissue analysis shows that leaves contain less P than N.
Edit: oh wait lol this is actualy what you were saying! Hopefully my thinking out loud here can still help.
It is actually the case that Orchids use more P and K than N BUT unlike N - P and K can be reabsorbed by the plant so long term it needs to absorb less P and K in the fertilizer compared to N just like Ray has suggested.
I don't think it harms them in any way to use the same ratio of N-P-K but they also don't seem to need to replace P and K as much as N so a 10-1-1 ratio has worked just fine for people and they reckon it improves things.
I used to use 10-3-10 but have since switched to a more balanced fert and I swear I see improvements so I think every time a grower tries something new they swear they see improvements. Who knows.
Actually I just checked, since I have switched to Akerne Rain Mix now. It has a ratio of
11,8 N - 2,7P - 13,7K + 11,8 Ca +3,5Mg + 4,8 S
So it uses more K than N and about 4 times less P. All I know is I have seen imrovements since using it
I can certainly see a lower P and K ratio reducing algae in pots so if it isn't really needed in such high doses then no need to.
But my akerne Ran mix actually contains more K than N and I trust the experts formulating the stuff and since I have seen improvements maybe K is needed as much as N
Last edited by Orchidtinkerer; 03-05-2021 at 10:08 AM..
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03-05-2021, 10:25 AM
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I honestly don't know what any of those articles convey, other than "we did this, and it worked", which can be said for a lot of nutrient studies. None of them conclusively said "N & K need to be about equal for all plants".
I would like to expand a bit on the tissue analysis thing:
First, it does not conclusively prove what a plant needs. It really shows nothing more than what the plant has been exposed to.
That said, in tissue analyses of wild-collected plants shows what's locally available nutrition. In a "niche plant" as highly evolved as an orchid, I can see that possibly being close to what that particular population needs to survive and replicate - certainly more so than plants in cultivation, where the nutritional inputs can vary widely.
I doubt anyone can argue that a plant in cultivation is often healthier, stronger and a better performer than it would be in the wild (assuming the rest of the cultural parameters are good), but that may have more to do with the available mass of nutrients than the ratios of the ingredients.
If we truly wanted to know what the plants truly require, we'd be looking at hundreds of thousands of a single clone, with "upteen" thousands of variations in nutrition, and that would only give us a general indication, as it would be difficult to know if reaching level "A" of a particular nutrient improved things just by the mass, or because it was there in the correct proportion to one or more of the others, if it compensated for the deficiency or excess of another, etc., etc.. Then you'd have to do that for each and every other type of plant...
I guess the bottom line is to do "what works" to eliminate deficiencies or excess, and don't try to shoot for a nutritional ideal.
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03-05-2021, 10:38 AM
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Ray,
Does the 133 ppm my true TDS or is that 133 Nitrogen? I always hear people growing with example 150 ppm is that their nitrogen level or just all of the dissolved solids they have?
---------- Post added at 07:38 AM ---------- Previous post was at 07:33 AM ----------
I did experiment this morning with distilled water and adding back some tap water. I just did a small amount for the test but it was still just the 10% tap. The result of that was PH 6.89 and TDS was 25. The PH came down but the TDS really came down. Now I believe that is too low.
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03-05-2021, 05:06 PM
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Senior Member
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Join Date: May 2005
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Quote:
Originally Posted by Shawna
Ray,
Does the 133 ppm my true TDS or is that 133 Nitrogen? I always hear people growing with example 150 ppm is that their nitrogen level or just all of the dissolved solids they have?
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There should be no nitrogen to speak of in your water, so that would be the TOTAL Dissolved Solids, not a nitrogen concentration.
Quote:
I did experiment this morning with distilled water and adding back some tap water. I just did a small amount for the test but it was still just the 10% tap. The result of that was PH 6.89 and TDS was 25. The PH came down but the TDS really came down. Now I believe that is too low.
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That's not too low at all, since that's just the base water with no fertilizer dissolved in it.
Let's say you're going to use the Orchid Pro once a week and want to use my recommended 100 ppm N solution.
Orchid Pro is 7% N, so each gram of that you add to water will contribute 70 mg of N. You want about 100 ppm N, so that would be 100 mg in a kg (1 liter) of water, meaning that you'd need to add 1.5g of the liquid to a liter (giving 105 ppm N - close enough).
Each gram of Orchid Pro contains 70 mg N and 114mg of other nutrients (184 mg total), so your 1.5g/L solution in distilled water would be 105 ppm N, but 184 x 1.5=276 ppm TDS.
If you added that same 1.5g/L to your 133 ppm TDS 50/50 water mix, the solution would still be 105 ppm N, but would have a TDS of 276+133=409 ppm.
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03-05-2021, 07:57 PM
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Ray,
I understand a lot more about the ph and the tds now then I did before. Do you sell the K-Lite fertilizer?
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03-06-2021, 08:05 PM
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I don't know how to do grams. Can we do this in teaspoons or ounces? And I do the 1.5g just to a 1 liter bottle instead of a gallon container?
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