DWC pH swinging like crazy

[grownnotflown420]

maybe its your ph meter , what brand ?


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just a cheapo one from amazon man, like £10 (15usd) for both EC and pH pen

When i can afford to i plan on purchasing the blue lab truncheons

oh dear , that may be your problem bud .

They need to be wet at all times , i let mine sit in a glass of water after use . change water every few days .

calibrate it in silution and check again , then let sit and see what gives


next time
Get milwaukee brand . hands down the best man .

A good ph meter is top priority my friend .

i have the mileaukee mw100 , got on sale 3 yrs ago for about 120$ canadian, damn best ive ever had .

calibrate once a week with ph4 and ph7 and keep pribe dipped in water always , because it will cause wrong readings



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damn that models expensive here in the UK unless i import from elsewhere in Europe.

Ive just bought the milwaukee ph55 - seems to be midrange from a brand you recommend

so we'll see how it goes once it arrives

going to pick up more pH buffer fluids tomorrow from my local hydro store. so fingers crossed...

[Trex]

cool


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[Ukbudz]

Buffering capacity of water is related to the volume and the amount of base feed as the base feed holds the buffers eg bigger volume and more base feed the more stable ph will be, this is one of the reasons i swapped to rdwc from dwc. I went from phing 25 litre buckets once a day to having a 160 litres and phing twice a week. You'll find the further into the grow you progress the more feed you will add thus increasing the nutrient solutions buffering capacity and stabilizing the ph more.

Though I always found a swing through the ph range made for bigger better plants, my ph would swing up through the range, I would ph to 5.2 then let it ride through to 6.5 then repeat.

[Ukbudz]

Are you adding cal mag back into your ro water also mate?

[Treetrunk]

Are you adding cal mag back into your ro water also mate?

I've got soft water and cal mag is a must add. I've found out


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[Trex]

Are you adding cal mag back into your ro water also mate?

I've got soft water and cal mag is a must add. I've found out


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oh yes , rekon i told him this yesturday


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[grownnotflown420]

Morning chaps, @Trex @Treetrunk @Ukbudz

Thanks for all the info man, so I noticed something weird with the pH down I was using and I might be completely off with this.

So the pH down I was using was a horticultural grade product, not specifically for hydroponics, its a 5l bottle and the dosage states '200ml per 1000l', so my guess also is that its not particularly designed for MUCH smaller applications.

Either way I've replaced it with some vita link ph down, I've also just got some ph buffer 4 & 7 to calibrate my trashy pH pen until my other one arrives.

I've mixed up a fresh batch to go in the res with dechlorinated tap water, upped the feed to 2ml/L so the Ppm is sitting around 500 (including 100ppm from the tap water). I've mixed it up in a brand new steralised 25l bottle and it appears the pH is sitting comfortably at 6.4 (too high I know, i havent Ph'd it yet)

How long do you guys recommend leaving it between adding pH down and recording the pH?

My baby needs to go in ASAP so hopefully this is the one

Failing this I may build an auto pH mechanism from some pumps and a raspberry pi so it can drip pH down as and when it needs to because right now I'm ready to set fire to the grodrobe

Thanks again guys, your time and words are much appreciated

Edit : yea im adding calmag at a rate of 0.5ml/L, I'm going to up this today to 1ml/L to see if this helps stabilise the pH

Very good point about volumes etc, I used to run a 90l res in a drip feed system, ironically my first ever grow and it went amazingly lol just wish I had the room to get that setup going again

[seymore_budz]

Hey buddy. So what I think is going on here is your airstone is causing some offgassing of co2 and increase in oxygen that causes a spike in PH. RO water doesn't have any buffer so the symptoms will be exacerbated. Tap water holds a lot of calcium bicarbonate that buffers out the effects. It's completely normal and should be expected. Adjust after 24 hours and it won't move too much after that. More feed will help as it will help to buffer the water.

If you see a sudden drop in PH then worry. Hope this helps

[grownnotflown420]

Hey buddy. So what I think is going on here is your airstone is causing some offgassing of co2 and increase in oxygen that causes a spike in PH. RO water doesn't have any buffer so the symptoms will be exacerbated. Tap water holds a lot of calcium bicarbonate that buffers out the effects. It's completely normal and should be expected. Adjust after 24 hours and it won't move too much after that. More feed will help as it will help to buffer the water.

If you see a sudden drop in PH then worry. Hope this helps

Thanks so much man, I think with the help of all you guys I have hope that this next batch will be the one

I do agree with your comment of the off gassing of Co2, but I went from RO to tap water to see if that had an effect, trial and error never hurt anybody lol!

I also changed the air pump to a smaller one, the one I was using before was a bit of a beast, I had it lying around so thought why not, then thought about the whole injecting more warm air, causing water temp to rise, chiller working harder, cost more electricity!!!

Thanks again man

[seymore_budz]

Hey buddy. So what I think is going on here is your airstone is causing some offgassing of co2 and increase in oxygen that causes a spike in PH. RO water doesn't have any buffer so the symptoms will be exacerbated. Tap water holds a lot of calcium bicarbonate that buffers out the effects. It's completely normal and should be expected. Adjust after 24 hours and it won't move too much after that. More feed will help as it will help to buffer the water.

If you see a sudden drop in PH then worry. Hope this helps

Thanks so much man, I think with the help of all you guys I have hope that this next batch will be the one

I do agree with your comment of the off gassing of Co2, but I went from RO to tap water to see if that had an effect, trial and error never hurt anybody lol!

I also changed the air pump to a smaller one, the one I was using before was a bit of a beast, I had it lying around so thought why not, then thought about the whole injecting more warm air, causing water temp to rise, chiller working harder, cost more electricity!!!

Thanks again man

No problem buddy. You will get there for sure. The same effect will happen with municipal water but it won't be as aggressive. RO water will change PH if you put your hand in it. H20 is the world's most aggressive solvent when pure.

When it comes to DWC, my opinion is more air the better :) the effects of heating your water are minimal and reducing the risk of root rot should be top priority. More air mitigates the risk. I think you can overthink these minor details and forget the most important ones.

If the PH issue is a massive problem you can buffer with a bit of CalMag but the PH will still climb for the first 24 hours then settle. Personally, in DWC where the stability is key, I'd be mixing my RO water with municipal water at about 50/50 as the bicarb will stabilise the PH as well as provide a small amount of sterilisation properties to the mix. Liquid oxygen is another option but it doesn't hang about for too long like chloramine does. Anyway, I'm waffling, good luck bud