Coco/perlite runoff ph issue

My runoff varies between 7.1 and 7.4.
My input ph is 5.5 to rectify high runoff ph and my runoff is about 50%.
Its been a week now,watering every second day and it wont drop below 7.0 to the 5.8 i want it at.
Im using general hydroponics,feed once a week and am in week 7 veg.
I wouldnt mind problem solving it with a good flush using a 3.0 ph water. BUT common sense urges me to seek advise from those that have paid their schoolfees already rather than stress my ladies. I truly value any solid input .
Many thanks …

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3.0 would kill the plant. Im a hydro grower, the soil guys will be here soon I hope

I grow in rdwc and neoprene collars and I’m just wondering why your ph is running so high…?
As stated above , I would not run water through with a ph any lower than 5.5 …
Now did you clean your coco and perlite before using… you usually dont have to clean perlite but I’ve heard of certain coco brands needing to be flushed before using… I believe that’s your problem… also how big are the plants… I know that people think that you can’t overwater coco , but I call bull$hit on that… every other day seems a bit much and could be building up bad bacteria and throwing your ph off , but like I said… there is a reason that this is happening… just need to figure it out…
Sorry I cant be more help… :wink:


Hey peachfuzz.
No i never rinsed it.
Plants are about 50cm and 20cm tall. We heading into summer and temps this week average 34°. Bigger plants are needing water every second day in cloth bags but younger ones could still go another day. First indoor grow and i want it as near perfect as i can make it. But this flood of conflicting internet advise on all little aspects is overwhelming but still fantastic fun working it all out.

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Thanks for advice boardsbird. Glad i wasnt impulsive…

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Give Us a photo if you can, that helps

what is your water source? RO, rainwater, straight tap, filtered tap, or well water?

If your planning on a flush I wouldnt use RO or distilled unless its cut with some tap water. I’m not sure about flushing in soilless media like coco. There are a lot of adhesion sites in coco. definitely dont flush with pH 3.0 water

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Hi there. The water is from a farm dam supplied by a natural spring and winter runoff. Ph is 7.0 without nutes. Thought a good flush would do the trick and flushed with 5.5 water two days ago and first 10% runoff was 7.1 and measuring it at the end where it rose to 7.4.
Im extending watering to every 3rd day after peachfuzzes comment about bacteria.

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Are you seeing any problems? Or just that your runoff is too high? Honestly if you arent seeing any problems I would just continue on with the 5.6ph water or so, your root zone should correct any issues.
As for Coco, it usually is good to give it a good flush every 3 - 4 weeks. Make sure you add a little nutrients to the water so you arent flushing everything out.

Hi Aolelon
3 bigger plants (50cm)looking good.
3 smaller ones (20cm)have a deficiency with yellowing of lower leaves and purple stems. I feed once a week.10ml/10L , using general hydroponics micro,grow and bloom.
I was advised to flush with clean water,then to add nutes every watering till its back to 10ml/10L.
So start with 1ml/10L then 2.5ml then 5ml then 7.5ml finishing back where we started at 10ml/10L and resuming the once weekly feed program.
Sound good ??

Is a farm nearby? Is it conventional or organic? Just concerned about runoff and contamination. Have you water quality tested? Some of these conventional commercial farms should be considered super fund sites…

Very good point indeed.:+1: Makes so much sense now you led me to think of it. Im having problems with surface waterplants in a large ornamental fishpond for the last two years i’ve been here. They grow like weeds just about anywhere,highly invasive like hyacinth but here they barely surviving. I assume im looking for any chemical abnormalities as NON organic fertilizers is still the way they farm here.
Brilliant,that gives me a direction to move in.


Coco should be one of the easiest mediams to ph if your to high or low so its a good choice. Depending on the size pot and what type of Coco you are going to have to keep running your ph’d water in the top until that is what comes out the bottom, that simple. However, you are probably going to have to use three times the amount of water per the size of the pot. 10 gal pot x3= up to 30 gal of ph’d water. Also, if you are using liquid nutes make sure its at the same ph as your water.

95 days and 63 days.
Could this water be affecting them or do they look ok for their age and growing normally. Did have nute lockout on younger 3 and have flushed.
Moby dick are smaller 3.
Strawberry amnesia are bigger 3.
Both dominant sativa’s with about 30% indica.
Never posted a picture in my life,prefer simplistic and practical over technology and confusion. lol
Hope it works and thanks so much for taking the time to let me know im not alone and contributing to sort out my ocd ph dilemma. Experience and wisdom i too can pass on when my time to give back comes. Really appreciate it guys…

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well yeah depending on what crops they are growing and if there has been any use of chem fertilizers, fungicides, pesticides, herbicides. Pretty much going to find glyphosate anywhere and mercury, cadmium, flouride, arsenic, aluminum…heavy metals and… nitrates, sulfates chemical contamination, nuclear contamination cesium 137, iodine 131 pretty much is everywhere but esp in the western US.

You can look up these soil and water tests online…

need to see a support ticket to get all the info. They dont look too bad but should be bigger for their age IMO

To create a grow support ticket we need some basic information to help diagnose the issue.

COPY/PASTE the below list into your forum post.
Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA

  • Strain; Type, Bag seed, or NA
  • Soil in pots, Hydroponic, or Coco?
  • System type?
  • PH of runoff or solution in reservoir?
  • What is strength of nutrient mix? EC, or TDS
  • Indoor or Outdoor
  • Light system, size?
  • Temps; Day, Night
  • Humidity; Day, Night
  • Ventilation system; Yes, No, Size
  • AC, Humidifier, De-humidifier,
  • Co2; Yes, No

Hey man pots are huge and i sponge runoff from a geyser driptray. SPONGE OFF :tired_face:
Im sure i can sneak them out under the cover of darkness to give them a good and solid ph’d flush till they come right.
Timings good as the scrog frame needs to come in to start my first hst by supercropping them.
Will do it and update on results,thanks man.

[quote=“hangthebanksters, post:17, topic:24627”]

  • Strain; Type, Bag seed, or NA
    Dinafem moby dick and dinafem strawberry amnesia.
  • Soil in pots, Hydroponic, or Coco? 50/50 coco/perlite
  • System type? Insulated wendyhouse.
  • PH of runoff or solution in reservoir? First 10% Runoff 7.1
  • What is strength of nutrient mix? 10ml/10L grow micro and bloom from general hydroponics. No meter for EC, or TDS. Will be purchasing one this week.
  • Indoor or Outdoor
  • Light system, size?
    Viparspectra 900w reflector series and Viparspectra 1200w reflector series.
  • Temps; Day, Night
    Night 14°- 21°
    Day 21°- 36°
    Battling with temp control. Current 9 day heatwave starting today and temps expected to go to 43°
    Night temps will rise about 6°
    while daytime temps about 10°.
  • Humidity; Day 40-60%,
    Night 50-70%
  • Ventilation system; Yes, No, Size inline extractor fan. 250 cubic meters an hour and my room is 15 cubes volume.
    Inlet airflow aided by boxed floor fan.
  • AC, Humidifier, De-humidifier,
    AC with humidifier. 12000btu
    Removes 450 cubic meters of air an hour. Its pulling in way to much hot air from outside and battles to keep temps at 27° while drastically dropping humidity !! . So presently not in use.
  • Co2; Yes, No
    Yes i make a 5L sugar,yeast and bicarb mix once a week.
    Will move to bottled co2 as and when money becomes available. Cant measure ppm levels as a meter is hugely expensive here but you get very dizzy in there after 10mins​:joy::rofl:

Western Cape in the Republic of South Africa. Yeah man we come from far and wide looking for valuable knowledge. Just been legalized here…yeeha…but discretion is always king with a sprinkling of fear. We may be legal but we up to our necks with petty theft issues. Thanks hangthebanksters,i will definately follow up on water testing. Goodnight! which is what it is here…