Air stone positioning

sven_lordy

Active Member
Hey all

Quick question - I have a big rectangular res, with the plant placed to one side rather than centrally… I have a 25w pump and a 200mm diameter air stone. I’ve been running the stone directly under the net pot and I’m running sterile.

The question is, if it’s oxygen in the water, as opposed to bubbles round the roots, does the position of the air stone make a difference? I ask because this is my 5th attempt at DWC. I’ve had beautiful white roots in the water since they first landed in there last Tuesday. The roots have started to tangle at the ends (rather than clumping) and the roots above the water line have suddenly started to take on a slight tinge. They’ve been beautifully white all the way up to today. Definitely not at rot stage, but have encountered this every single time as the precursor to rot starting.

I’m wondering if the air might be a little too aggressive for fragile young roots? Would it do any harm to move the stone to the opposite side of the res, rather than directly under the roots? Or is this generally not recommended?

I’ve done everything right and I’m damned if I’m going to lose another one. Think I’m giving up on DWC if this fails.

Other info – plant is receiving 500ppfd, 16/8 cycle. Room is 25c @55% humidity. Res temp kept strictly between 18.5-19.5c. PPMs currently just under 200, from RO water at 2ppm. Seedling was topped at the 5th node 3 days ago, with sterilized nail scissors (soaked in isopropyl for 5 mins then air dried before use). Internodal branching started yesterday and has accelerated today. Res is black plastic, with a LDPC pond liner, and foil bubble insulated all round. Zero light leaks, res only opened once per day for pH/PPM testing

Thanks
 

hotrodharley

Well-Known Member
Don’t overthink simple things. It doesn’t matter. I’ve stopped using airstones. I just weight the line and let it rip. The goal is aeration of the solution.
 

Johiem

Well-Known Member
Mine grid the whole bottom of rez, then again I make mine. I've not encountered problems with bubbles directly under the roots.
 
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