Early K-lite results

[gonewild]

1.45 grams per gallon is closer to a 1/4 tsp than a 1/3.

But the grams per liter table is the one to look at

50 ppm N is 0.38g/L or 380 mg/L(PPM). Conductivity should come out to between 600-700 uS/cm (on top of the base water).

OK. I'm reading the label of the K-lite container which says 1.45g (1/3 tsp).
During general use the difference between 1/4 and 1/3 tsp won't matter much but at this point we need to have an accurate amount to do the calcs.

Somewhere the Math was off by a lot to jump from 600ppm to 1600ppm so this is good to talk through.

 

[gonewild]

Well now it turns out that 200ppm N is actually closer to 1600ppm (not 500ppm).

Is that still an amount you are comfortable adding to orchids? That's a pretty foreign environment. I didn't find anything close to that in the jungle data.

1600 ppm is on the strong side but if a person is only applying fertilizer "once in a while" that rate won't hurt plants that are not salt sensitive.
In reality considering all the fresh rain Renee's plants get that strength may well be similar nutrients to what your plants get.

What we really need to see is what is the content of the media moisture inside her pots. The fertilizer spray she puts on may very well be diluted 50% as it mixes with the water in the pots.

So many questions about what actually happens insid ethe pot!
Her pots we know retain about 70 g of fertilizer water. We can assume that they also would retain 70 g of rain water. But NOT 140 g of fertilizer water and rainwater. ONLY 70 gms. total.

Math now.....

If the media is holding 70 grams of rainwater with 0ppm N and then she applies 70 g fertilizer water that contains 100ppm N how many ppm of N does her media water contain the next day?

But this only tells us what the available nutrient content is in the media. We don't know if the orchids can get it or how much they can get. Perhaps they get the most advantage rapid absorption from the actual fertilizer water contacting the roots.

oke:

 

[Rick]

Somewhere the Math was off by a lot to jump from 600ppm to 1600ppm so this is good to talk through.

I was computing backwards from N and forgot that the N is as NO3. A nitrate molecule is 4.4X the weight of just the N.

So 100 ppm of N starts out with a mass of 440 mg/L. Now start adding in all the Ca/Mg, and associated anions. So rather than adding it back up bit by bit, I just looked at the table from Ray's website.

Also as long as you know the mass per gallon (1.45g/Gal) just divide that by 3.785 to put that into mg/L. 0.383g/L

There's also waters of hydration that make up the mass of material in a teaspoon, but that won't get picked up by a TDS meter. The TDS meter would probably end up picking up about 600-650 mg/L of the 770 mg/L in a 1/2 tsp to make up 100ppm N K lite.

So in RO or rain water, to get 200 ppm N you'd weigh up 1540 mg/L, but the meter would probably see about 1200ppm of it.

 

[Rick]

What we really need to see is what is the content of the media moisture inside her pots. The fertilizer spray she puts on may very well be diluted 50% as it mixes with the water in the pots.

She's already told us that the 70 gr weight addition in the one pot was gone by 20 hours, and the stuff was dry at the beginning. Renee's numbers also don't seem off base if you check out that table from the Antec site I posted.

Aliflor wasn't made to hang on to water, just wick it up from a tank source. On a pass through basis it retains very little water and drys out fast. Its a very poor choice of material for top down watering only.

 

[gonewild]

So how much fertilizer does Renee need to apply to correct the problem?

My opinion based on current info (changes daily)..
Renee has been applying the correct amount but what she is applying is not being available to the plants.

The solution is:
1. Increase fertilizer dosage strength.
or
2. Increase the frequency of fertilizer applications.
or
3. Build a roof to block the rain.

And added to the above I'm not sure she has a nutrient problem.
Seeing her pictures and considering it is winter I don't really see a big problem. Old leaves turning yellow and falling off is normal and in the pictures there does not seem too many.

 

[gonewild]

She's already told us that the 70 gr weight addition in the one pot was gone by 20 hours, and the stuff was dry at the beginning.

Did she say the pot was dry at the beginning? Or did she say it was ready to be watered? (to many posts to look back through)
What would it have weighed the next day had she not watered it?

Aliflor wasn't made to hang on to water, just wick it up from a tank source.

Was it designed to wick nutrients up or as a support to hold roots as nutrient water was pumped over it?

On a pass through basis it retains very little water and drys out fast. Its a very poor choice of material for top down watering only.

I think it is an excellent choice for top down watering in conditions where there is a lot of top down water applied. For Renee it solved several other problems. It just needs to be watered everyday with nutrients, which is the way I like to grow if possible. If you know the exact nutrient level your plants perform best at, by watering everyday with nutrients you can have your plants growing 100% everyday at the top of the wave. Applying nutrients once a week causes growth to grow up and down over the curve.

 

[rcb]

Renee...

Can you please tell us...
the amount of K-lite you use to make your concentrate.
How much water is in the concentrate mixture.
How much of this concentrate you put in your 20l sprayer.

Do you have tds meter or does a friend? (You can get one at ACE Hwd for about $20)
Measure the tds of your fresh water.
Measure the tds (ppm) of your concentrate
measure the tds of the solution you are applying with the sprayer.

Measuring the water that is inside your growing media would be very good.
This is not so hard to do, all you need is to collect a spoonful.
Get a clean dry tray that will hold water.
Before you water your plants collect samples.
Sit a plant in the dry tray and tilt the pot so it is at an angle with the drain hole down and some small amount of water should drain out the drain hole. This water is your sample. Keep doing this until you have collected enough water to test with the tds meter.

If the above does not yield any water try doing the process the day after the plants are watered. Or if you happen to be home when it starts to rain try to collect some of the first water to drain out of the pots.

The result of this test will tell us the concentration of salts in the water in your pots. Ideally this water will represent the amount of nutrients that your plants are getting.

3.5 tsps into 1 gallon warm water which is then all added to my 20l sprayer. No I don't have a TDS meter, I can get one. But I'm heading out of town here in two hours, so it will be a while.

 

[rcb]

Ok, you all have given me so much information, I can't thank you enough. But as you have said, I need to take it all, sort through it, think about what is possible for me to do with my specific limitations and proceed. I'm going to be traveling for the next couple days, so I'll have plenty of time to do this.

I still owe you all some answers, and as I get them I will let you know. I will be able to check in periodically, so if you have any other questions, just ask.

Again thank you all especially considering you don't know me, you have been amazingly attentive.

 

[Ray]

A 3-Part Post

3.5 tsps into 1 gallon warm water which is then all added to my 20l sprayer. No I don't have a TDS meter, I can get one. But I'm heading out of town here in two hours, so it will be a while.

That concentration is - according to the label - about 565 ppm N. If you're diluting that to 20 L (I'm unclear of that from this post, but I hope so), the application rate is around 105 ppm N.

Back to an earlier part of this discussion - we really ought to be using mass, not volume when discussing application rates. The bulk density of the K-Lite is 15% lower than that of the MSU RO formula, for example, based upon the fill height in the jars I repackage. That might push Renee's dosing to 85-90 ppm N, still not too bad if it's retained by the potting medium.

Concerning the TDS, calculations throw us off a bit. For 100 ppm N, it takes 0.77 g/L. 0.77 g/L is 770 ppm (actually a bit more, as the dissolved minerals will decrease the volume of water in that liter a bit). But how do we deal with the hydrogen and oxygen atoms that come along with the ingredients? Do they contribute to the TDS? Do we only include the cations in the TDS?

 

[keithrs]

Again thank you all especially considering you don't know me, you have been amazingly attentive.

What ya saying?oke:

 

[tomkalina]

Lance - I have to think that someone has determined the TDS of K-Lite at 50-100 ppm N in pure R/O (Rick?) unless everyone is blending with higher solids water for the micro-nutrients. As soon as my tank is full of fresh R/O (hopefully today) - my plan is to add 1/3 tsp/gal and measure the TDS. I'd like to measure pH as well, but my pH wand has died. Stay tuned....

 

[rcb]

I spoke to the local water facility today.

They use CaOH to adjust the pH to 7.

They still use Sodium hypochlorite instead of chloramine.

They have now started testing TDS "every so often" and over the past year it "comes in" between 20 and 200 mg/l.

He said they haven't changed anything recently.

Ray - yes I dump the whole gallon into my sprayer. Glad to know my math was right because I did check it to make sure recently.

 

[ALToronto]

Concerning the TDS, calculations throw us off a bit. For 100 ppm N, it takes 0.77 g/L. 0.77 g/L is 770 ppm (actually a bit more, as the dissolved minerals will decrease the volume of water in that liter a bit). But how do we deal with the hydrogen and oxygen atoms that come along with the ingredients? Do they contribute to the TDS? Do we only include the cations in the TDS?

I will test this out using Na2O and report back. I agree that we need to get a handle on TDS measurement. Has anyone here actually calibrated their TDS meter using NaCl, as recommended?

 

[Rick]

I will test this out using Na2O and report back. I agree that we need to get a handle on TDS measurement. Has anyone here actually calibrated their TDS meter using NaCl, as recommended?

I have calibrated mine against KCL, which is an ASTM standard.

Within the operation ranges we play with, NaCl and KCL are almost identical.

 

[Rick]

It just needs to be watered everyday with nutrients, which is the way I like to grow if possible.

Which I think me and Keith also advocated, but sounded like it was going to be to much of a pain to execute. Which is why I advocated adding the trays to extend the holding time.

 

[Rick]

But how do we deal with the hydrogen and oxygen atoms that come along with the ingredients? Do they contribute to the TDS? Do we only include the cations in the TDS?

I mentioned that earlier Ray.

oxygen attached to nitrogen (aka Nitrate) is a complete molecule with mass that reads as TDS (both by conductivity estimation, and real TDS measurment by cooking off the water in an oven).

The waters of hydration (which are attached to the calcium and magnesium nitrate salts) are essentially salt bound water that you can never dry out completely. Those just go to water when the salt is mixed. It adds mass to the dry salt, but not to the conductivity/ TDS measurment. So that's why my fast guess to the TDS question is 600 mg/L as opposed to the 770 with the difference mostly due to waters of hydration associated with the two biggest salts in the recipe.

 

[Rick]

The meter does measure ms. Had a lot of caffeine this morning. Have always watered around 1 in growing months and .5 in other months.

Coffee in growing months and beer in the 0.5 months:wink:

This could make for some extreme conductivity measurmentsoke:oke:

On the other hand Jean Lux does coffee each morning and beer at night.

So his measurments must go up and down each day!!!

 

[Rick]

They have now started testing TDS "every so often" and over the past year it "comes in" between 20 and 200 mg/l.
.

With that amount of variation it could be useful to get your own meter.

 

[gonewild]

Which I think me and Keith also advocated, but sounded like it was going to be to much of a pain to execute. Which is why I advocated adding the trays to extend the holding time.

Yes you did and I don't disagree. I like growing in trays. In fact I like to use the side hole drainage pots so each pot has a reservoir but water as normal from the top.

The problem I see for Renee is the rain flushing the trays and removing the nutrients. IF this occurs the trays don't solve the nutrient problem. Plus if she plunges the current root system into water it may cause some root loss.

 

[gonewild]

With that amount of variation it could be useful to get your own meter.

I wonder what is the cause of the variation?
If they add enough CaOH to raise it 180ppm doesn't that add a lot of extra Ca?
How does the addition of CaOH effect the Phosphorous in the fertilizer solution?