ph problem

Discussion in 'First Time Marijuana Growers' started by wmemae, May 25, 2009.

  1. #2 FlowerGirl, May 25, 2009
    Last edited by a moderator: May 25, 2009
    I've had this problem before with certain manufacturers.

    Rockwool is spun rock, and some of the rock is limestone. There may be residual lime in the rockwool, and lime raises pH.

    I used to rinse and soak them under a faucet and then draw out the water with a turkey baster. Then I would soak them in the 5.5 water overnight. It helped somewhat but in the end I stuck with Grodan and have no problems with just the plain soaking.
  2. wow I would've never thought of that . I soaked them and then checked there run off and came out to 6.0 after soaking in 5.5 and then reajusted the water and then left them soaking again
  3. anyone anybody
  4. #5 TrichsR4Kids, May 26, 2009
    Last edited by a moderator: May 26, 2009
    flowergirl hit it right on the head. you should have flushed them out before soaking them in a mild nute solution. this is a common problem with rockwool.

    check into AOK rockwool starter plugs by GRODAN, they come pre soaked and have their natural neutral pH.
    It could be your water source maybe? Hydro can be finicky if you don't use R.O water.
    R.O is a must for hydro imo but I'm convinced the problem is the residual lime in your rock wool.
    i use Silica Stone now, no more rockwool.
  5. I am using gordens starter plugs . I soaked them first and then re adjusted the ph and let then soak again I never used a light nute solution. I found other threads that said I could be the air stone
  6. I'm guessing thats what Trichs meant.

    The airstone is a good observation, from my understanding airstones under certain conditions actually deplete minute levels of CO2 from the water causing pH to rise, this is heavily debated in the Aquatic community and I keep an 18 gal. res with 15 gallons of solution in it with a 4 inch airstone and a 28GPH pump, never have any problems.

    What size is the res? What is the res temp? How much air are you pushing into the res? What is your water source? These are all things that can effect pH, using rockwool included.
    It could be a couple of these things combined or maybe just one. I'm sure you'll narrow it down eventually and correct it. Hopefully before they start to grow bigger and depend on the res being more optimal.

    The pH in smaller resevoirs can swing quicker and more often and can be more difficult to maintain than larger ones.

    Also I thoroughly rinse my RW then soak it, not soak it twice.
  7. thanks flower girl I am trying to narrow it down and another grower told me it could be alge and heis right but that might not be the onley prolem . I cleand out the res added new water and nutes and cleand out the res with water and a sponge and it still jumped so I just adjusted th ph again and took out the air stone , and we'll see what happens. the temp of the water staye at 74 75 It is a 25 gallon but I have onley 5 gallons in there couse thats all thats needed I had tje stone running all day but yasterday I set it for 15 min befor each feeding and I feed 12 times a day for 15 min each , and I use gordens rock wool and pete pellets as medium
    me having only 5 gallons in there would not make it spike within an hour

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