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PH fluctuation?

Discussion in 'Hydroponics / Aeroponics' started by Roullette, Nov 4, 2008.


    Roullette Well-Known Member

    in a 5 gallon bucket DWC style..

    how often should the PH fluctuate?

    is going from 5.8 to 6.6 to even sometimes 7.1 within 24 hrs a bad thing?

    or is that a normal amount of fluctuation for a DWC with 4 gallons of water?

    Bullethead21 Well-Known Member

    That seems a bit high for DWC system. I think you want aroung 6.5 at the very highest but more like 5.8 or 6 is better. It needs to stay the same or very close at all times or you will shock/stress the plants.

    There could be many things casuing it to flucyuate like that. I would use distilled water to start with and go from there and see if it still changes that much.

    What kind of nutrients are you using?

    PH is a tricky thing sometimes. I wish someone would post a clear howto properly adjust PH when first starting a fresh tank in a DWC or Bubbleponic system. Do you treat a gallon at a time while adding each gallon of water to your tank? When and how do you add the PH up or PH down basically. There seems to be more to it then just measuring PH, then adding up or down chemical, stir well until disolve ph up or ph down chemical is dissolved, then measuring ph again.

    So if someone could post some details on PH adjusting that would be awsome!

    Roullette Well-Known Member

    use distilled water. take 4 gallons at a time add my nutes check the PPM an if its where it should be then i PH it out.

    I use technaflora nutes, Do 1/4th their recommended dosage. an at 1 month olds the PPM is at 350-375 and will increase the PPM every time i need to change the rez.

    but like i said i check it at night an its 5.8 an the next following night its at 6.3-6.4 and sometimes i see 7.0 or higher but no higher then 7.2.

    im just wondering what causes the PH to fluctuate.

    Does the plant use certian nutes which makes it more acidic or less acidic when other nutes are not being absorbed?

    I changed the rez from 250-275 to 350-375 on sunday an the ppm is at 288-310 in certian buckets. all the PHs are at different levels. ranging from 5.9-6.6 like i said earlier.

    also i use the liquid style of ph up an ph down.. dont know if that makes a difference

    Bullethead21 Well-Known Member

    You need to start with PH correct water first of all. Before you add nuts the PH should be correct if Ive read correctly...someone please step in if Im wrong but Im pretty sure that instrustions said that PH needs to be right BEFORE you add any nuts to your water. That could be your problem and why your PH is all over the place I bet....

    But to answer your question, yes, some of the plant even same strains may use up something it needed and that missing from the water can change the PH level as nuts are being eaten by each plant.....

    But even so, you should still mix in the correct order which is starting with correct PH water right off the bat, then add all the other nuts your gonna add. You should also mix the nuts in the last remaining gallon and mix it well, and THEN add it to the tank (res). Some just dump the nuts right into the tank which is really not the proper way to mix in your nuts to get the most out of them. Liquid stuff is a bit different than powder though I would imagine but I would still follow the same mixing process.

    switch10 Well-Known Member

    I add nutes first then ph down after a few minutes. all nutes that i've used adjust the ph. Mine goes to 7.0 exactly using sensi bloom/grow a and b. I lower it using some pre-mixed ph down. If you add the dry ph down directly to the res, the ph will slowly lower, tricking you into adding more ph down. I throw 4 teaspoons in a gatorade bottle, then add RO water then shake well. Adding 1/2 cup lowers my 18 gal res's ph .6 about. I try to wait about 5 mins in between doses of ph down.

    Roullette Well-Known Member

    " PH of the solution = 6.02 (if not adjust to 5.8-6.2)"

    thats quote for quote from my nute sheet.

    solution is the mixture you made. so no you dont have to add the nute to PHed water. the chems you add will make the water more acidic, or less..

    none the less this int helping my situation... once i get the answer ill post it. thanks guys

    Roullette Well-Known Member

    the only thing i did find out is bacteria can cause such a "violent" PH fluctuation. but its new water and the roots look great.... almost too good

    doubt its that.

    NoDrama Well-Known Member

    You PH balance the water AFTER the nutes are mixed in. If you did it before you would have a very acidic mixture as the nutes will drive the PH down further.

    Roullette Well-Known Member

    thank you:hump::hump:

    Bifta Well-Known Member

    the problem is the nutes you need to get it right for each bucket ph going up means plants need more nutes ph going down means use less nutes
    wot stage are your plants at ?

    Roullette Well-Known Member

    vegging an there about 30 days. i think they do need more nutes an will be adding more tomorrow.

    Bifta Well-Known Member

    yes m8 deff more nutes
    how tall is he/she ?
    are you changing nutes for flower stage ?

    hockeyplayer New Member

    calibrate that ph meter,, sounds to me you might have some rez on your tool,,

    Roullette Well-Known Member

    tools less then 3 weeks old

    herballuvmonkey Well-Known Member

    One thing no one has mentioned yet. You are using small reservoirs. I never use less than 10 gal rez's because the Ph use to fluctuate widly like yours. As the plants drink especially if they have some size to them u will be ph ing every day because the smaler volume of water. Here is what I found out over time...switch to 10 gal rez. Use distilled water and put it in a larger 35 -50 gal. trash can and ph it all at once. If you want u can even ad the nutrients if u want, just make sure u keep it in the dark so no algae will grow. also keep more plain distilled phd water on the side. why? because if u ppm ur nute water to 1000 u can calculate by the volume of the res as to how much to add to get it to wherever you may be (i.e 400ppm). u need clean water to go with it to dilute it. this way saves time and u wont be going crazy ph ing ur water all the time. more water= more stability. Also the more intense the light, the more your plant will drink.

    Roullette Well-Known Member

    yea that was my original thought. the plants drink the water use nutes an make the water more acidic or less depending on what they use.

    i had them into a 16 gallon bin but on my 1st grow i had a male that the roots got entangled an had to cut them an leave in the rez which over time began to rot an mold. hygrozyme helped alot with that an didnt cause my plants to get sick or die but figured that 5 gallon buckets is easy way to move a male out.

    thanks for all the replys on this topic guys..3rd DWC 1st time doing actualy strains.. spent alot of money an time on this an would be very upset to lose them to a PH fluctuation,:hump::hump::hump::hump:

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