RDWC 4 weeks in veg, pH drop, EC drop, water drop quite a lot: need little help

[zeusdraco]

Hello everyone,

Its the second time i use this current config of my RDWC, here the setup for my 10 plants spot.

-70 gallon approx overall.
-Waterchiller, i keep water in the 20-21.5 celcius range
-Humidity , i keep the humidity at 65 RH , i gonna lower it at 60 RH soon
-Room temp 75-79F , it lower a bit during their sleep at about 72-75 F
-Waterfall ( pretty slow it help to move the water around )
-Bottom drain system, i only use it when i change my res.
- 10 x 7w airpump each bucket have 2 airstones in it. ( there is 2 speed , i am on the lower speed ) MC3000 quiet airpump.
-XL bag of CO2 x 4 ( stay pretty much in the 800ppm Co2 )
- I use semi closed neg pressure room, very little fresh air, 2 x 4 inch inline and 1 hole without fan as intake in neg pressure in a 16 x 30 feet room.
- I also use 3 x 8 inch carbon filter with ac infinity to move air around and filter it , 1 x 6 inch carbon filter with ac infinity, these only filter my inside room air.

On the nutrient and water side.

I use GH line, micro, floragrow, bloom, diamond, dr marijuna and Z9 by flying skull enzimes part 1 and 2 and cyco sillicium,

So i fill my 70 gallon of osmosed water ( brand new carbon 2 week old ), add my silicium and wait 1h.
I then add my GH micro and wait 2h
I add after Floragro, florabloom, diamon, cal/mag, a little premixed DR marijane or it create some stain , adjust ph if needed and add flying skull Z9 lastly.

ATM i do 2.5 x 70 for micro, bloom, grow and 5x 70 cal/mag, it give me approx 800 or so PPM or 1.2-1.3 EC.

I check PH 2 time per day. at Midnight i boost my PH close to 6.4, the morning when i check it back its down to 6.0 or so and the next day its midnight its close to 5.7 or so PH and PPM dropped from 800ppm to 780ppm , sometime more up to 760ppm.

I had this problem before boosting my ppm from 200ppm to 300ppm after the first week, 300ppm to 400 ppm second week and since the third week ( been 2 weeks) i decided to follow some input given on this forum about giving them more ppm, so i decided to boost at 800ppm or close, still my PH drop like no tommorow.

I dont have any roots rots, the roots are white or at least were 2-3 days ago.
I tryed with or without dr marijane, without silicium too
I tryed with and without waterfall so the water doesnt move as much ( seemed to be tiny less worse but hard to say )
I tryed with Perfect PH for 100gallon PH stabilisater, i think it was even worse then.
I stopped the waterfall for now coz it might drop slower but again i am not sure at all.

I never had ph drop like this before, previous run went, very smooth with the perfect PH i didnt had to put much anything to stabilise it.

So i am now clueless on what could be the problem.

The only thing i changed from the previous growth is my airpump i was using 5 x 65w i think commercial airpump with 8 outlets these thing was just horribly noisy for 10 x 7 w quiet airpump MC3000 in low mode, the room is now on neg pressure with little intake of fresh air but 4 x XL Co2 bag that keep the room at approx 800ppm, sometime 1000ppm co2 overall. My plants growth still quite nicely but if i skip checking PH, they slow right away or go in deficient mode etc..

If someone can help me it would be appreciated.
Sorry for my english, i am french canadien

Thx

 

[LKABudMan]

Could the extra co2 with the new pump be causing the acidification?

 

[zeusdraco]

I was wondering that maybe it could be but when i read grower everywhere using Co2 in their room they doesnt speak about any problem regarding their airstone pumping Co2 into the water causing PH fluctuation. But that something maybe someone know ?

I though it could be a pathogens also , i cleaned my system 12 time with bleach, alcool, peroxyde, after removing some root into my bottom drain that stucked there before the pump head ( not submersed pump 4 of them for my bottom drain ) but i actualy didnt check if there was root going through the waterpump on the otherside guessing root couldnt go through pump or it would have broke up.

Any help is appreciated.

Thx

 

[Smokey0418]

There are no pics just an age in the title.

I run a 4 pot system , chilling 30-35g . One of my plants is 4 weeks and the others a bit older but not bigger that’s for sure.

My thinking is this . Your ec is high but I don’t run co2 so maybe if you do you can run your ec at these levels.

My ec is .75 or 375 ppm ph’d to 5.9.
I run silica calmag and two part grow with hydroguard and orca .
My ph is like like a rock with the ec stable as the water goes down.

That’s my feeling.

Now on the air pump, I can’t find much discussion on it here but have found some info and have been doing a few things myself .
Like shutting it off and living off the waterfall return.
Have I notice differences , I think so but without scientists and witnesses it’s just here say.

Enjoy and good luck

 

[sneekymofo]

I just read through the this very quickly so I may have missed something, so please forgive me, and my French is MUCH worse than your English so please, no apologies necessary!

First, I don’t think your water should be dropping much at all in week 4 of Veg. The plants can only drink so much when they are young, and they are still very young. In a 40 gallon RDWC I can put NO water in for the first four weeks and have no issues, so something is seriously awry, here. Figure this out first or you are chasing ghosts.

Second, I’m not quite sure why you would start your pH so high? I generally try to shoot for between 5.6x and 5.8x, then let it drift up, then drift back down by the end of the week, giving the girls a full assortment of nutrient availability during the week.

Your TDS number will be a bit hot at 800, but the less finicky plants will take forced feeding like that, and if your nutes have pH buffers that may help with some of your fluctuations. BUT, as I started with, you should not be losing water like that at those temps, those plant ages, etc. My money, for what it’s worth, is there is a mechanical issue that is compounding a biological or chemical issue, so try to keep changes small and simple until you figure it out.

Don’t know if you’ve seen the chart already, but it’s been a lifesaver….