pH rising too fast in DWC

[SolKing]

Hi 420, I recently tried my hand at DWC as my Hempy cups were not performing as expected and I wanted to have more control over the root environment as well as being able to check up on the roots.

The standard DWC setup seemed simple and cheap enough for me to try so I bought a cheap but powerful air pump and a small plastic container that can hold a liter of water with enough of a gap left that the bottom of the plant medium does not sit directly in the water.

I soaked the air stones in ph 5.5 water for just over an hour and the ph rose to 5.6 in that time, I have an Amnesia clone in rockwool that had developed quite a strong root system so I decided she would be given the honour of being my first true hydro girl(thanks to heaps of bad luck now my only vegging plant of this pheno, it's slightly older clone sister just opened her legs in the flower room to show me some beautiful mini bud sites first time I've grown a plant to the point where buds are forming so a big milestone in my green career)

The res was stable at 5.8 740ppm and the first two days the clone was in the DWC all was gravy the roots exploded and height almost doubled, then on the third day when I checked the res I noticed a slimey substance on the roots so I gently washed it off then checked the ph to find it was at 8.2! The plant had drunk about a 1/4l of water with hardly any nute uptake as the ppm rose by 200 which should therefore lower the ph but it keeps rising, that third day I brought the ph back down to 5.9 (btw I use fresh lemons to ph down) and the next day it was back up to over 7 with more gunk forming so I changed the res and cleaned the air stones and res then reset back to original ph and ppm. The next day it rose again and no matter how many times I adjust the ph it keeps rising back to over 7 and if I leave it more than a day it will climb past 8, the clone which was exploding in growth has now completely stopped both in root structure and plant structure and the leaves are developing a bleached look starting from the tips.

Can someone advise as to why my ph is spiking so radically as I can't figure out what it is. Also I used a 1/2 and 1/2 mix of mineral and tap water for the first res then when I realised I would probably be chucking out that water every other day the next two res changes were with just tap water at 140ppm, the nutes I use are Hesi hydro and the Temps inside my cab are about 80 degrees at the moment.

Any help is greatly appreciated

 

[mokel]

heya,
sounds like you got something ugly developing inside the root system ... furthermore i'd use vinegar if not commercial ph up and down without anything organic then anything fruity like fresh lemons for ph control .....
as you hadn't mentioned anything i would guess that you run a non sterile environment without any hydroguard or other beneficial bacillus and it might even get to hot in the water which also benefits bad stuff growing there ...

as i lack the necessary experience for such a case i have pmed of VilliageIdiot, i think he should be able to give you a much more experienced point of view in this case and be of a much greater help


edit:
you might want to check out this one > Tea Bag your DWC < for example which was a great help for myself when i started and gave me a lot of first impressions about this particular topic

 

[Serpent]

Hows it going sounds like you know a thing or two about DWC sure your not pulling any arms trying to trick people you know your shit your just babying them to munch i thing with the little water you have its like a fish tank theres a lot going on and you only have the plant in 1 litter of water so when your roots are feeding water is evaporating things change super fast with so little water but a bigger set up like 1 gallon or more the water is more stable takes time for the water to fluctuate

 

[SolKing]

Hi Mokel thanks for taking the time to reply, finding that link and for asking for additional help. Correct I admit I jumped into DWC without fully accessing the situation and am now suffering for it, other than giving everything a good clean I have not added any sterile products or introduced any beneficial bacteria.
In my research whilst frantically trying to save my lil girl I did come across both the heisenberg tea and the warning not to introduce any organic matter, I am staring to think it's down to the bits of lemon that hitch a ride into the res when I squeeze the juice in so I will try a different ph down while I brew my tea and hopefully that mitigates the affects a bit.

Checked the res Temp just after lights out and it read 17.5C which would be on the cold side?

I'll try these remedies and report back. Once again thanks for the speedy reply

 

[SolKing]

Hi serpent cheers for taking the time to reply, I assure you I am a complete newb, my lil clone will attest to that if it survives lol.
I am aware that the small size of my res is affecting the ph balance but honestly this is as big as I can go until sunny old England decides to finally lift this hypocritical prohibition on nature! Hopefully the tea and change of ph solution remedies my situation I will post results of my endeavours.

Once again thank you for taking the time to reply

 

[Papageno]

Well I would say thanks first to the kind words from Mokel.

Now to the situation at hand I think I have not enough info but I can throw a few things around.

First I was going to ask about the res temps which you say you got cooled off. A temp over 23C will be something where you must run a living res. At 20 and below it makes it difficult to run a living res but still better than running sterile IMO.

So the second question is about the setup. I am having a hard time visioning what you described. pics of the setup would be great help here. But is your res in an opaque material? we can't have any light in the res at all. all of the holes where the tubes are going in must be sealed tight so not light gets in. this can be difficult since we have an intense light right above it.

If you want to use organic stuff that is fine but you must understand what that means. It will break down and eventually rot. Without a living res organics must be regularly dumped.

Speaking of which...you have to make a decision now and either go sterile or living. You can switch back and forth during the grow but you can't obviously successfully do both at the same time.

So to help we really want to know a few details about the solution you have cooked up. We want a few days of res measurements documents so we know temps, PPM, pH and water levels. With that info we can know what is going on. I think you are saying your water is dropping and the PPM is stable so the plant is fine but the res is spiking in pH.

Now you claim it is slimy now which means you may have root rot (pythium) which may be the root cause. There are a lot of ways to solve that. take some pics of the slime for us to see and we can talk about that.


All that said.. I suspect that the medium was not thoroughly washed before use and has caused some issues in the res. That or you have light leaks in the res and you have algae or something else growing we don't want.

The solutions are varied. I just saved a guys grow convincing him to stop running sterile and drop in my tea. He had an out of control pythium problem and was running a chiller and every type of chemical he could to get rid of it and nothing worked. One day running the living res and all is fixed. At the end of the link above on teas is my recipe. You wont need everything in there as it has a bunch of extras to enhance bloom and make big flowers and you don't care about that just now.

The key is you need to introduce the stuff through the medium.

So assuming your res is opaque and sealed well... dump the contaminate res and clean it thoroughly. Before introducing the net pot back you need to take the net pot to a sink and rinse the hell out of it. Get everything out. wash the outside and run sopious amounts through the medium. Now you may have a clean system outside of what you couldn't get out of the roots zone.

Next... well it depends on how you want to roll. I would use my tea. You can buy good stuff at a store. Lets say you go down and buy something like Orca at the store... Next you want to 80% fill the res with a light solution. Since we will be adding more in a sec make it about 700-800 PPM for the 80% of res then when we add the rest the nutes will be down closer to like 500-600 ppm. Then mix up the Orca in the 20% top off with a concentration for the entire 100% of your res. Then you take that strong solution and introduce it through the medium. Pour it directly into the net pot over all those messed up stones and roots.

Now you have a clean system with a good nute base and concentrated bacteria all right in the root zone fixing the problems and some in the res preventing future disaster.

That's a start.

 

[Fuzzy Duck]

Lemons are suggested to have a PH 2. some thing which most would think that is pretty strong acid... but it is the type of acid it is which is citric & not very strong at all, not really going to buffer PH value of the water/nutrient solution for a very long time i'm afraid.

More likely better of getting a commercial grade PH down either nitric for veg & phosphoric for flowering, not sure how those would effect a living culture nutrient solution tho for dwc ?

 

[Papageno]

i use that stuff... the orange and blue food grade stuff from General Hydroponics.

It doesn't matter if you are growing in living or sterile. You don't want to add that stuff straight to the res. It will cause lockup and can kill things like suggested. That said I have done it a ton of times myself and never had a problem.

Your system should be in control so you mix up your top off and then pH it as we all do then top off.

If your system is out of control then first figure out why and get it back into control...that may mean dumping the res.

To make a quick adjustment use a measuring cup, like 2 cups or 1 liter in size, and dip out some of the res and add the adjustment there and then introduce it slightly diluted. Or do like most of us and dump it in there.

You should not be trying to maintain a tight range that is bad for many reasons and is false folk lore. As long as it is in the happy range you leave it alone. If it is above 5.4 and below 6.2 you don't do a thing. If it starts to creep out you adjust the PPM to get the res stable again. If it is crashing one way or the other you need to figure out what is wrong.

I usually adjust my top off to be close to 5.8 unless I am nearing an edge and I want adjust the top off to compensate.

If you try to use chems to keep it tight you loose all the info about what is going on. If you are doing things right it will stay stable.

 

[SolKing]

And the award for the most misleading username goes to...

Hello villagegenius and thank you for taking the time to reply. Let me say Mokel was not wrong he has indeed inlisted the help of a hydro guru!

My setup is as basic as it gets I'm afraid, unfortunately materials are hard to come by in my area so I have had to take a 'make do' approach to this whole grow starting with the fact that I do not have net pots or hydroton as hydroton seem to not exist in my area and the net pots available were far too large, so how is the plant suspended you ask? Plastic garden string is the answer I'm afraid, although I did soak it in Ph'd water before I used it it is criss crossed under the lid of the res and acts as a rest for the rockwool to sit on, with my limited space and materials this was the only option to hand I could think of that wouldn't cost much.

I am away from my cab atm so will get some pics for you later, the res is light tight other than a small gap between the lid and the rockwool which I covered with an opaque plastic lid which seems to do the trick. The res itself consists of some air stones and nothing else, I was only using lemons as they were cheap and natural, just what I like and it worked fine with the Hempy cups I just kinda assumed it would work fine with DWC too, oh the naivety!

Yesterday after work I went out and got some distilled malt vinegar as I heard from a few sources that it is a good ph down to use so I did another full res change and clean and then reintroduced everything back in, I'm reluctant to buy commercial ph down as that means going to a hydro store which is a big no no in my country and also from all the stories I've read of people who have introduced these beneficial teas they have said they no longer need ph up/down so didn't make sense to spend a tenner on something that may be obsolete before I can use it properly but if the vinegar and tea don't help then I will get some.

A couple of hours after the res change using vinegar and things look a bit more hopeful, the res has not turned cloudy the water still looks drinkable other than the slight yellow colour from nutes and the ph only went up 0.4 in that time which is not bad for me considering how bad it can get, adjusted it slightly as I knew it would keep climbing during the night and this morning it again had only risen a few points so at least a step in the right direction has been made.

I am fully on the side of beneficial rather than sterile as I believe mother nature will do a better job than we can seeing as she has 100s of millions of years of practice under her belt, I am in the process of tracking down the ingredients to use for my tea as even bloody earth worm castings don't seem to exist in my area fml! Where is the link to the tea you speak of? Hopefully my lil girl can get through this and fulfill her destiny of filling my bowl peace and thank you for your words of wisdom I will report how things progress

 

[SolKing]

Hi fuzzy duck and thank you for taking the time to reply, I have seen the error of my ways with the lemon juice and have discontinued it, hopefully I didn't make just as big a mistake by using vinegar instead haha guess I'll find out when I get back lol. I heard that commercial ph up/down dissipated in an oxygen rich environment, is this true?

Thanks again

 

[Serpent]

Wow i did not even think about res temps i need to rent villiageidiot this guy knows his stuff

 

[SolKing]

So this is what we have as I said very basic, the main reason for the small res is this container is the only one I could find that fits nicely into my pc box as I want to maximise what little space I have to work with. It might just be my mind playing tricks but since replacing the lemon with vinegar the newest growth at the top does seem to be gaining some colour.

This is inside the res, the roots were longer but when cleaning them a lot of the ends came away.

The air stones aren't that bad for being freebies thrown in with the air pump which other than the noise is also better than expected, this pic was taken with the pump on about 1/4 strength maybe less. Anyways happy growing.