Ph issues.

[noodles.au]

indoor
Growing Medium:
Vermiculite

Growing Style: DWC
Watering/Feeding Frequency: Res change weekly
Nutrient Strength (PPM/EC): PPM meter is coming.
PH Levels: 5.5 - 7
Temperature/Humidity Levels: 33degrees c water temp 20-26 degrees c
Air Flow/Fans etc.: 2 exhaust 1 intake
Lighting Type (CFL/HPS/MH etc.): CFL
Total Wattage: 2x130w 6500k
Growth Stage: grow
Plants Age: 2 weeks
Cannabis Strain: bag seed.

 

Hi Guys I am having a PH issue with my first deep water culture, tap water here is ph 7.6 I try to leave it out for at least 24 hrs prior to going in to the DWC I add dutch master GOLD ONE grow (60ml), add.27 (60 ml), silica (15ml) and zone (15ml due to high water temps)  I then top up the water level and check the ph then lower the ph to around 5.5 - 6 and let it settle with the lid off as the plants are in another container the same size as the DWC res.

 

Later I check the ph again and its stable. when I add the plants within a few hours the ph starts to rise again which is fine I expect some fluctuation but within 6 hours or so the ph is back to 7.6 I have checked to make sure no light is getting in the to res and have tried to lower the ambient room temperature and the res temperature.

 

I have a large air stone and a pond pump that pumps 200liters an hour to keep the water and nutrients mixed. IS there something I am missing???????

 

I am thinking of taking them out of the vermiculite and soaking it in low ph water to see that stops the ph going up so fast.

 

Also the roots have just started grow down in to the res should I lower the water lvl to below the net pot to let the vermiculite dry out a little.

[Ozzy420]

Welcome aboard.

 

Your water temps are getting to high for DWC.

 

Best water temp for DWC is around 21c higher temps of the water hold less oxygen in the water and cause you probs.

 

Try and keep water temps at 21c and you will do a lot better...

[noodles.au]

Hi thanks for the reply its not that easy keeping the water temps that low, would it be advisable to use bleach or h2o2. I am going to be setting up a recurculating system soon that runs through a chiller of some description when i macgyver that shit up .

[Naycha]

It would not be advisable to use bleach, I personally wouldn't bother with H2O2 either.

 

Get that chiller hooked up asap.

 

Naycha

[Ozzy420]

H2o2 will add ozygen to the water at the same time it will kill any good bacteria in the water that can leave u open to more probs.

 

As nay sid a water chiller may be needed, wile you water temps are high you will have issues...

[noodles.au]

Ok So I have done a lot of reading over the last week or so and while my roots where getting brown they where not slimy I have since flushed everything and cleaned everything and came to a couple of conclusions that might be the problem.

 

Firstly, I made the rookie mistake and had my water levels too high. I noticed that I could get the ph of my nutrient mix stable for hours but after flushing the old mix and putting the new mix in the PH would gradually go back up to 7.4, so it seems over saturation of the media was the cause of that.

 

So with high PH and less than optimal water temps my nutrient mix started getting chunky and brown and this was consistent in color to the dutch master silca that I had been adding.

 

i noticed solidifying when I added silica to the undiluted nutrient mix. Another rookie mistake and a waste of my first DWC mix as it had to be discarded, when adding the nutrients individually straight into water this didn't happen except for some minor clouding of the nutrient mix.

 

on a brighter note I have moved the "room" to a diffrent location so I can better control the temerature and have flushed everything and cleaned everything thoroughly some of the roots that went brown are still there but are growing and are not falling apart when touched which makes me think again of the silica as some of the browning has even gone.

 

water levels are alot lower now as the roots have grown out of the pots they are looking healthy despite some discoloring from what i assume was nutrient lock out.

 

water temps are lower not optimal but substantially lower around 20 at night and 22 during the day I have set the 200l/hr pump with a tube sticking a bit out of the water sort of like a water feature and it is creating more water turbulence and so far PH has remained stable around 5.5 increasing to max 6.2.

 

hopefully I was just over thinking it with the root rot as they seem to be powering along and the roots are so far fine I will be dropping back down to medium strength dutch master zone at next res change.

[nici]

My ph usually fluctuates for the first couple of days when I change the res but stabilises after that.  When using silica its suggested that you add it to around 500ml of plain res water before adding it to the res to dilute it, this should stop the clouding you are having.

[noodles.au]

My ph usually fluctuates for the first couple of days when I change the res but stabilises after that.  When using silica its suggested that you add it to around 500ml of plain res water before adding it to the res to dilute it, this should stop the clouding you are having.

I did as you suggested with the silica worked great thanks.

 

I have rigged up redneck cooler its a flood and drain system for my reservoir where the water gets pumped out to a separate container well away from the lights that has  2 frozen water bottles in it and once the water reaches a certain level it drains back into the reservoir and stays at a stable 22 degrees c and I just change out the water bottles every 6 hours or so depending on the ambient temperature.

 

My tap water after standing for at least 24 hours is still ph 7 and an ec of 0.5 what I would like to know is would it be better If I used a phosphate free acid buffer for aquarium's that lowers the ph and softens the water by converting the KH to co2 instead of using ph down. I figure this seems to be a more natural way of lowering and stabilizing the ph instead of just dumping some acid in the water (ph down).

 

Dutch master recommends a ec of 1.5 but I have read that I should go lower is this correct.

 

thanks in advance.

Noodles.

Edited November 20, 2013 by noodles.au

[Naycha]

That pH solution sounds like a bad idea to me, you want the water to be as aerated as possible not to have CO2 in it.

 

Naycha

[noodles.au]

That pH solution sounds like a bad idea to me, you want the water to be as aerated as possible not to have CO2 in it.

 

Naycha

What about an acid regulator that precipitates calcium and magnesium softening the water and lowering the ph.