pH increase after draining and refilling

  • Thread starter Pimpernickel
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Pimpernickel

36
8
I'm on my first RDWC run and I have drained and filled my system twice. Once I had some algae growth so I scrubbed the buckets drained and refilled them to get most of it out. I drained it again yesterday when I switched to flower. Each time my nutrient solution increased ~1.0 by the next morning, what causes that?
 
desertsquirrel

desertsquirrel

1,177
83
What media are you using? That might cause it.

Also how long are you letting the water sit before you fill it?
 
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Pimpernickel

36
8
I'm using hydroton that I washed well before starting. I use RO water, HG nutes, plus a little CalMag. I'm in the third week of flower and I started from clones, I haven't seen any large fast pH swings anytime other than when I drain the system to change nutes. When I drain I pull a PVC/Uni-seal out, let it drain, put it back together, dump 30gal RO water in and drain again.

The nutes are aquaflakes A&B mixed at 1/2 aggressive str, 50mL CalMag. Then I pH. Then full strength Drip Clean, 1ml/gal everything else, no algen.
 
QuarterbackMo

QuarterbackMo

810
93
I'm using hydroton that I washed well before starting. I use RO water, HG nutes, plus a little CalMag. I'm in the third week of flower and I started from clones, I haven't seen any large fast pH swings anytime other than when I drain the system to change nutes. When I drain I pull a PVC/Uni-seal out, let it drain, put it back together, dump 30gal RO water in and drain again.

The nutes are aquaflakes A&B mixed at 1/2 aggressive str, 50mL CalMag. Then I pH. Then full strength Drip Clean, 1ml/gal everything else, no algen.

Mine does this too... Instead of 5.8 ph to around 5.4 and let it drift up to about 6 then knock it back to like 5.6 or so and don't use any ph up in the topoff... If you got your strength right you shouldn't have to adjust your ph for a nice little min...
 
G

Grampa_Watt

11
0
do you make a feed up and pH adjust it straight away or leave to settle first?
does your pH meter have a dial for solution temp? temp will affect the pH, is your res inside your room? is it the same water temp as the feed you mix up?
are you using anything in the feeds that is a pH up? i.e. liquid silicon, rhizotonic etc if so what dosage?
if using tap water with lime content, evapouration will increase the pH as the lime becomes more concentrated within the remaining feed.
is the EC of the feed solution staying where you set it? if she takes more feed than water from the solution it will increase the pH and if she takes more water than feed the pH will drop as the feed becomes more acidic (lower ph higher EC).
few things to think about for you mate, though as problems go ot aint a biggy. just re-adjust, i would only start to worry if you are using excessive amounts of phosphoric acid as it will break down to P in your feed solution and excessive amounts could lead to lockout. that brings me onto something else too what are you using for a pH down? Nitric acid will not remain stable as long as phosphoric acid.
take care bud and good luck with your garden.
Gramps.
 
D

Disco Duck

203
16
This is normal for me. I mix the solution 24 hrs in advance, but any time I change the water (once per week) the PH will go up about .8 over the first 24 hrs. Happens too me every time, until the last 2 weeks. For some reason it doesn't happen at all with the bud boosting mix, that mix stays where it is when I put it in.

For me going up .8-1 in the first 24 hrs is normal. I check it every few hours and add like 5ml of PH down at a time until it is stable. For some reason, Evergreen enhances this effect and it really shoots up with Evergreen in there. It goes up about 1-1.2 if there is Evergreen in the mix, and it happens faster.
 
PaperStreet

PaperStreet

1,149
263
It is normal for PH to fluctuate dureing new setups and complete res changes thru cycles I've seen it a million times it happens u shouldn't experience any problems if u Ph ur system once daily to 5.8 or as otherwise stated 5.5 is better its kinda a sweet spot to start new Dwc at or even new res changed systems at for that matter starting low gives the system that much more room to play while trying to establish or reestablish itself in a new system. Once daily is all u need the fluctuation should reside within the First week and begin to balance itself.
Otherwise u have problems. Stinky water? Root slime? Rot? If that's the case H202 should Clear up any probs u may have real fast but u have to. Catch it early.
Otherwise a good preventative maintenance u can add To maintain a healthy res from there would be by adding. Beneficial bacteria. To combat the bad bacteria that causesall those problems like rot etc.
Like I said if u don't have bad water probs relax its totally normal. For a newly established as Well as a newly changed out res ph to fluctuate its nature its ur res tryna establish or reestablish a. Happy. Medium. For ur roots to reside in.
Peace
 
P

Psycho gym

10
3
I'm using hydroton that I washed well before starting. I use RO water, HG nutes, plus a little CalMag. I'm in the third week of flower and I started from clones, I haven't seen any large fast pH swings anytime other than when I drain the system to change nutes. When I drain I pull a PVC/Uni-seal out, let it drain, put it back together, dump 30gal RO water in and drain again.

The nutes are aquaflakes A&B mixed at 1/2 aggressive str, 50mL CalMag. Then I pH. Then full strength Drip Clean, 1ml/gal everything else, no algen.
try pH adjustment the next day
 
Aqua Man

Aqua Man

26,480
638
What are you using for ph down and usually not always if your ph is going up it's good. When it starts dropping is possible there is a problem.

What stage of growth and how much are they drinking a day?

Your ph is changing but what are you ppm changing in a day and are they going down or up?

Are you running sterile or live?
 
L

linky

54
8
I rinse my hydroton really well first, then I let it soak in a container with full strength nutrient solution for a day (ph of ~5.5-5.8) then before using it I rinse it out again with freshly mixed nutrient solution.. the ph will rise badly with hydroton when new. Doing this has helped not only with more stable ph at first but healthier plants in the beginning of veg.
 
bigdaddyg8

bigdaddyg8

591
93
do you have a chiller? and do you use UC roots? i don't think algae growth in DWC is a good thing.
 

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