I Really need some help here with my PH fluctuations in DWC

[MrGreenfinga]

So i have a 19L Rez and use the flora tripart line with the GH ph up and down and my ec is 500 i got 1 seedling in a Net pot rn and isnt growing really fast even slower than soil

 

shes in a rockwool cube covered with Leca

roots havent hit the water yet 

and shes in the middle too (Rockwools not on bottom)

 

the big question is why the hell does my water have such big ph fluctuations

 

I use RO water and i ph my water everyday

i add a milliliter or two of ph down daily and the next day my water is around 6,5 again

yeaterday i Left it at 5,0 and today it was 6,5 Really frustrating 

 

Does anyone have a clue?

[KC]

At a guess I'd say your reservoir is too small? I don't do hydro but I'm sure some hydro heads will come along soon

 

 

19L isn't a typo is it?

[MrGreenfinga]

I mean its Deep water culture 

pretty normal to do it in 5gallons

because its only a single plant per bucket

and i see what you mean

the bigger the less fluctuations

i just heard a guy say he had his so stable he only had to check it every 3 weeks or so and for that i would need a fucking ocean

[catweazle1]

The solution is to allow the pH to rise to 6.5, then acidify back to your target pH. The reason for the fluctuation is actually loss of dissolved carbon dioxide (carbonic acid) through agitation from the bubblers.

Edited January 11 by catweazle1

[catweazle1]

It's the hardest system to get right. It was too frustrating for me when I did it some years ago. I didn't understand the problem then. The actual way to maintain acidity in this situation, I think, is to treat the carbon dioxide as the acid source and either inject it on demand or bubble it through constantly, using a settable pH monitor to control the influx of gas. A carbon dioxide alarm is an ABSOLUTE MUST to avoid poisoning risk. It will fall to the floor and rise like water in a sufficiently enclosed space.

Edited January 11 by catweazle1

[stu914]

PH for DWC should be set at 5.5 and allowed to drift up to 6.5 before re-setting,

this gives all the elements in the nutes the best chance of being taken up.

 

Rockwool can cause ph fluctuations very rapidly and has to be treated before use,

airstones will also affect ph, better to use a pump to create a 'fluming' effect.

 

A good sized rootball is needed before going into DWC, this is how I promote a rootball...place the mesh pot inside a solid sided pot and hand water from above.

 

19ltr is plenty for a single plant,  res temps are another consideration,

between 18c and 21c is ideal.

Much lower and it won't grow, higher and there's a high risk of root rot due to low dissolved oxygen levels in the nute solution.

 

I use 'rootit' cubes to start seeds/clones and 'Advanced PH Perfect' nutes for the grow

which cuts out the need for any ph adjustment.

 

Have a look in my profile and you'll see how I get round a lot of issues

connected to various hydro systems...

Good Luck

 

 

Edited January 11 by stu914

[Shogun]

Best thing I ever did when growing in dwc was stop checking and adjusting ph. 

[MrGreenfinga]

@stu914

Okay so if i understand this right 

Youre saying that i should adjust it to 5,5 and let it go back up to 6,5 then down and back up through whole my grow?

 

and i got an Airstone running in there 24/7 

and it evaporates or messes with my ph?

 

[MrGreenfinga]

@Shogun

Isnt that pretty counter productive?

or do you have some sort of ph Perfect nutes going on?

[MrGreenfinga]

@catweazle1

I need some further explanation on this carbon dioxide talk

 

my airstone is supplying carbon into the water right?

and thats what messing with my ph?

its on 24/7 btw 

So what do i do about it if i dont have an Alarm

and how is it toxic to the plant dont really get it 

Edited January 11 by MrGreenfinga

[catweazle1]

36 minutes ago, MrGreenfinga said:

@catweazle1

I need some further explanation on this carbon dioxide talk

 

my airstone is supplying carbon into the water right?

and thats what messing with my ph?

its on 24/7 btw 

So what do i do about it if i dont have an Alarm

and how is it toxic to the plant dont really get it 

I can't give you an explanation on that method. It was just an idea that I may try out next year. Carbonic acid is unstable and is there when you take it out the tap. Any agitation will knock it out of the water and turn itn into CO2. This causes the pH to rise as the carbonic acid disappears. Carbon dioxide is toxic to you in high enough dose, hence the alarm.

 

Follow what STU914 said. This is the standard procedure.

[MindSoup]

5 hours ago, MrGreenfinga said:

@stu914

Okay so if i understand this right 

Youre saying that i should adjust it to 5,5 and let it go back up to 6,5 then down and back up through whole my grow?

 

and i got an Airstone running in there 24/7 

and it evaporates or messes with my ph?

 

 

I'm about as far from a hydro grower as you can get, but with hydro I'm pretty sure different nutrients absorb better at different points across that range of PH, so it's actually better to let it fluctuate. Like I say, not speaking from experience, but it's something I've seen said on here a few times over the years. 

Edited January 11 by MindSoup

[badbillybob]

your ph will be caused by the rockwool cubes.

the airstones will be fine, theyve been used for decades

did you ph the medium in your net pot before starting? im guessing not.

 

sort this out and you will be fine

[stu sleeper 20vt]

Roughly for dwc

If your ph is moving quick then your nutrient strength is off.

If your ph is rising then make nutrient stronger

If your ph is dropping then back off the nutrient strength 

Temp is also important...I like 18-20*c utilising fishtank heater

 

 

 

[Shogun]

5 hours ago, MrGreenfinga said:

@Shogun

Isnt that pretty counter productive?

or do you have some sort of ph Perfect nutes going on?

 

No it wasn't counter productive at all. I grew DWC for over 10 years. The last year I stopped paying attention to ph and ec. Zero headaches and my plants actually seemed to thank me. The nutrients were measured by a syringe only, no ec stick. If you are using the right nutrients for your water (and right amount) your ph should be close to perfect. I'm not necessarily recommending I'm just sharing my experience. The best results I've had were from keeping it simple and stress free.