[The.Cook]

@Blueberrydrumz sorry man but I cant get your question... What do you mean by "unbalanced"?

[dr-dank]

A great post indeed. Thanks and +k.

I run botanicare/canna coco. Normally no pre-rinse; I will sometime test ec out of the bag and get ~ 200 or so (starting with 30 PPM RO), which I assumed was the "pre-charge"/buffer of cal mag. (I know ppms suck, this is with hanna .50 conversion if I recall).

Things are going well and I normally don't measure runoff ph or ec. I use H3ads 6/9 with some epson salt added, final ppm about 670 PPM/1.4 EC (IIRC), ph to 5.8. I get a lot of runoff, to the tune of about 50%. Daily drain to waste. Given this I would think I am constantly flushing and expected to see parity between in and out EC.

I was surprised to see the cumulative runoff consistently coming out ~ 200 ppm higher than the in. I say cumulative because I do perpetual and so some plats are near to harvest and others have been in a week or so.

On one hand this would indicate salt build up and need to flush. But on the other as there is no problem, and I feed at a low ppm (6/9), and have so much runnoff, I am having a hard time thinking this is a simple case of excess salts.

Could there be some funky cation exchange where I am knocking off the pre-charge or something? Only one of the 8 or so plants are 1 week old and in "new" coco. The other are incremental a week older right up to one that is ready to harvest. Given this I would think any pre-charge would be lost in the noise of the older containers that, given the runoff level, should be flushed already.

Thanks for your ideas.

Regards

[The.Cook]

@Dr_dank: Maybe the runoff is just evaporating a bit... Ever tried to feed manually and test run off ec that way??

[Miraculous Meds]

Originally Posted by dr-dank

A great post indeed. Thanks and +k.

I run botanicare/canna coco. Normally no pre-rinse; I will sometime test ec out of the bag and get ~ 200 or so (starting with 30 PPM RO), which I assumed was the "pre-charge"/buffer of cal mag. (I know ppms suck, this is with hanna .50 conversion if I recall).

Things are going well and I normally don't measure runoff ph or ec. I use H3ads 6/9 with some epson salt added, final ppm about 670 PPM/1.4 EC (IIRC), ph to 5.8. I get a lot of runoff, to the tune of about 50%. Daily drain to waste. Given this I would think I am constantly flushing and expected to see parity between in and out EC.

I was surprised to see the cumulative runoff consistently coming out ~ 200 ppm higher than the in. I say cumulative because I do perpetual and so some plats are near to harvest and others have been in a week or so.

On one hand this would indicate salt build up and need to flush. But on the other as there is no problem, and I feed at a low ppm (6/9), and have so much runnoff, I am having a hard time thinking this is a simple case of excess salts.

Could there be some funky cation exchange where I am knocking off the pre-charge or something? Only one of the 8 or so plants are 1 week old and in "new" coco. The other are incremental a week older right up to one that is ready to harvest. Given this I would think any pre-charge would be lost in the noise of the older containers that, given the runoff level, should be flushed already.

Thanks for your ideas.

Regards

Heres a couple thoughts for ya. Ur not having any probs, but ur just asking why ppm is higher on runoff? If that's the case don't stress or change anything.

Ur testing sometimes when u start, so ur starting ec can really vary, if u haven't confirmed what ec each batch is.

2nd ur using ro water to test pre run, yet when u test the runoff, ur testing with 700ppm nutrient strength. Add that to ur intial ppm before starting and ur exactly at the right ppm they should be.

If u tested ur pre run runoff with a full strength feed, which id recommend, especially after u just read this thread, then ud see a run off ppm of 900 to 1200 I bet.

and yes u are diluting the pre charge. quit starting with ro water, and start with at least half strength feed or full strength.

[The.Cook]

@miraculous med: I think he's feedin with same nutrient solution, from the younger to the oldest.
If it's not a "test error" due to run off evaporation, it could also mean your feeding to much (also with regard to water / nutes demand). Maybe plants are transpirating a lot for some reason, taking up lot of water but not so many nutes, whose remain in the ground... Just guessin anyway...

[blueberrydrumz]

Originally Posted by The.Cook

@Blueberrydrumz sorry man but I cant get your question... What do you mean by "unbalanced"?

hey,

basically if i wouldnt break the buffer of my tap it would slowly rise towards 7 ... so i was asking if using a lot of P2O5 to take the water down to 4.5 to break the buffer and then bringing it back up to 5.5 will unbalance the water and maybe in the end unbalance my feed water?
Or will that be the case anyway as we want a acidic solution of around 5.5... and it doesnt matter how i get to 5.5 as H+ and OH- will never be in equlibrium in the feeding water as we are shooting for 5.5?
hope im getting my point across hehe
thx

[dr-dank]

Originally Posted by The.Cook

@miraculous med: I think he's feedin with same nutrient solution, from the younger to the oldest.
If it's not a "test error" due to run off evaporation, it could also mean your feeding to much (also with regard to water / nutes demand). Maybe plants are transpirating a lot for some reason, taking up lot of water but not so many nutes, whose remain in the ground... Just guessin anyway...

Thanks for the thoughts guys. The cook has it. I sometime test with pure RO when I have a new batch of coco. Yet to see higher than about 200, which I assume is pre-charge, so I don't flush.

I feed the same 6/9 ~ 650 PPM every day. All plants get the same, until last week when just that plant gets water.

I don't think evap answers this as I do the test within 5 minutes. Mix nutes, ph, measure ppm, water, collect runoff, measure ec.

If I had barely any runoff I think this would make sense. But as noted I get an average of 50%, which one would think would balance out the ions.

That said.....

It is hot/dry here. I am in somewhat small pots and some do get a bit light by the next water. Perhaps its the transpiration that explains the increased ion concentration. Still, if that were the case you might expect nute burn or as a symptom I could drop feed strength.

But 6/9/650 PPM under a 600 W in a 2x3' area already seems a bit low....

Regards

[The.Cook]

I think the only way to have a clue on it is to check them individually..

[Mikell]

Originally Posted by The.Cook

@miraculous med: I think he's feedin with same nutrient solution, from the younger to the oldest.
If it's not a "test error" due to run off evaporation, it could also mean your feeding to much (also with regard to water / nutes demand). Maybe plants are transpirating a lot for some reason, taking up lot of water but not so many nutes, whose remain in the ground... Just guessin anyway...

What I was thinking. If you aren't seeing any tip burn, I'd still be inclined to lower EC to 1.2 for a few plants (comparison) and see how they respond.

Everyone always loves pictures either way

[WaxyTaxi]

some great stuff here, lots to still understand and review. Thanks for this Cook.