coco pH won't go down - anyone encountered this?

I fill a smart pot with 3gl of coco, right? right out of the bag. I prepare a 3gl bucket with just RO water in it to wash the new pot. I pH it down to about 4! (shiny red in the liquid tester). Then I flush the pot with the whole 3gl of water. Runoff EC goes down from 1200 to 500. pH - stays 6.5, won't budge a bloody .1!

anyone can tell me anything about it?

I doubt if running another two gl will have any effect...

are you testing the run off that is 6.5? cuz thats not how you test coco ph you gotta get a hand full of coco and let it soak in water for a bit and then test. you need a ph pen it will make life much easier. you want to make sure you solution is at 5.5-6.2 ph 5.8 is ideal. usually when adding nutes it should bring your solution down if your adding it right. what brand are you using? are you using cal mag supplement?

shnazul23 said:

are you testing the run off that is 6.5? cuz thats not how you test coco ph you gotta get a hand full of coco and let it soak in water for a bit and then test. you need a ph pen it will make life much easier. you want to make sure you solution is at 5.5-6.2 ph 5.8 is ideal. usually when adding nutes it should bring your solution down if your adding it right. what brand are you using? are you using cal mag supplement?

Click to expand...

hey, thanks!

I use the soak method too - and get the same results pretty much.

I have a digital pen. I use a local coco brand (not in america), with perlite 50-50. No cal/mag supplement save epsom salt (magnesium sulfate) which carried me through the last grow.

The feeding solution is never above 5.8, and I always maintain runoff.

Any thoughts? thanks.

update: I continued flushing with 4.0 pH water, and as the EC went below 0.5, pH started rising. with 0.2 EC I get water IN @ 4.0, and OUT @ 7.0! would you believe that?

Im pretty new with coco and I really dont test the run off, maybe once. when you wash ur coco do you pre charge with nutes? I know if you flush your coco your not supposed to use just water there needs to be at least some cal mag added to fullfill the coco or you will just run into problems/ defeciencies. I use canna coco and use the COGR boards. when I get them I have to use a buffering solution and let the boards soak for a day before I use them. the buffer solution contains cal mag, and other nutes to pre charge the medium and brings it to the right PH. I wouldnt worry about the run off right now just make surre that your solution is 5.8 and u got 20% waist comming out and you should be fine

You should wash your coco always just like you would wash your hydroton. Coco comes with salt from the manufacturers. I also pre charge my coco chips with liquid Karma and Cal/Mag

yes i flush my coco with RO water then charge it with nutes till run off is 0.8EC
pH won't budge.

what im wondering is if your using ro water what is the PH of the RO water? why is the PPM @ 1200 in the first place? why are you testing the run off? I wouldnt worry about the run off so much your just stressing youself out just make sure that you water with nutes with 5.5-5.8 ph. I do this and dont even look at the run off and have no problems. the one thing to watch out for is the cal mag issue and do let the coc go dry.....NEVER!!!!! or defecinecies will start to occur. what nutes are u using??? You should try out CANNA nutes they are really good or House and garden. I use canna with an occasional guano tea to help the micro biology and it seems to work for me. this is where its at is the tea. the tea is the KEY

asaph said:

hey, thanks!

I use the soak method too - and get the same results pretty much.

I have a digital pen. I use a local coco brand (not in america), with perlite 50-50. No cal/mag supplement save epsom salt (magnesium sulfate) which carried me through the last grow.

The feeding solution is never above 5.8, and I always maintain runoff.

Any thoughts? thanks.

Click to expand...

could your product have doloimite lime already mixed in ?

so yeah i'm using RO water
no dolomite in the coco

I guess I really shouldn't be bothered so much about it many people say the coco is normal to keep a steady pH, and it's just the solution pH that's important. That's a bit strange cuz I did have some phenomena that's allegedly pH related... but oh well.

I'm almost thinking it could be your pH meter? I'd try it in a 4.0 or 7.0 solution and see. Just a thought.

i did man
just that week

Hmmm, sorry dude all that came to mind....mine was doing something similar and sure enough it was my meter.

Machnak, did you find a solution to the high PH? I have the same problem and it's killing me over the past few months. Whatever I do, I can't get it under 6.5. I measure it with a Bluelab multimedia pH pen. I've tried to flush with 2x, 3x the size of the pot with no result.

coco varies drastically from brand to brand. flush with plain RO, only adjust ph of nutes. coco tends to run high PH, feed often and PH nutes to 5.5-6 to combat high ph

That's why it's forgiving. Prepared coco will stabilize ph. It takes a lot to mess it up.

I've poured fert solution from 5.4 to 6.1. The 5.4 was a mistake on my part. From my understanding, coco allows a low PH to drift up.

I've never checked my run off. Maybe I did but can't remember. I'll claim acidic. Roots organic Premixed coco in a bag.

All I know. Hydroponic growth, no problems using a PH'ed solution that hovers around 6. My last three pours were at 5.8. That's two drops PH up. This evening's dose got three drops. After that, one drop. Then two, then 3 then back to one.

There never more then three batches with the same PH.


For what it's worth...

asaph said:

I fill a smart pot with 3gl of coco, right? right out of the bag. I prepare a 3gl bucket with just RO water in it to wash the new pot. I pH it down to about 4! (shiny red in the liquid tester). Then I flush the pot with the whole 3gl of water. Runoff EC goes down from 1200 to 500. pH - stays 6.5, won't budge a bloody .1!

anyone can tell me anything about it?

I doubt if running another two gl will have any effect...

Click to expand...

Is the plant unhappy? If the plant is growing healthy then don't worry about it as you may just create problems were none existed previously.

plan500 said:

Machnak, did you find a solution to the high PH? I have the same problem and it's killing me over the past few months. Whatever I do, I can't get it under 6.5. I measure it with a Bluelab multimedia pH pen. I've tried to flush with 2x, 3x the size of the pot with no result.

Click to expand...

6.5 is fine. If you ph your nutes to 5.8 and they end up at 6.5 in the coco, that's a nice little range.

I'm Having similar issues with my PH . my mix is 50% coco, 25% Vermicompost, 25% Perlite. using DTE 4-4-4 and 4-8-4. Run off PH is reading 8+ I checked with both a meter and a chemical test kit. i wash about 1.5 gallons of 4.0 PH distilled water through a .25gallon pot with no change

okay one thing i remember reading that might be similarly actually my issue now i think about it. to properly flush coco or reset a imbalance, ie when you want to run nute water to pull stuff out ionically the solution your flush solution(1/2 strength) your pulling through your plant should be at 25*C

this way everything shoudl fall out optimally instead of potentially getting held up in the media if its a lower temp perhaps?

my ph is stuck at 7-7.5 going to heat up the pot/plant media an then the feed an dump through flush solution an see if that helps at all

other than that plan is to use this similar tech for a complete drench an hope all the excess metabolites an crap become soluable an fall out in the drench