A question about dropping PH

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bigsyko75

Member
Need a little help here as i'm confused.
I was under the impression that when growing in DWC that this is how it works.
ec up ph down= add less nutes
ec down ph up =add more nutes
ec stable ph drifting slightly up =all good
So as i'm growing DWC in 3 DIY 20 litre black buckets i'm having a few problems with PH as this is whats happening.
ec is stable on all 3 bubblers and stays stable but ph keeps on dropping by maybe a point a day and i can't get my head around it,so what does this mean?
ec stable ph drifting slightly down =?
I'm growing under 2 x 400w hps.
Water temps between 19-24c.
Growroom temps 26c
Humidity 50%
Been on 12 hours 18 days.
I do a fresh res change every 7 days.
Last res change was last friday 22nd october and i reset PH to what it was before res change which was 5.8.
Saturday & sunday PH had risen to 6.0 then on Monday it started to drop very slowly and now for 2 bubblers PH is 5.7 and the third bubbler 5.8
Ec remains the same as to what i set it at it never drops or rises just the PH drops slowly,can anyone help me out.
Thanks.
 
Heisenberg

Heisenberg

Well-Known Member
Water level is also important. Is your water level dropping everyday? If so, things don't sound too bad to me. If the water level drops AND the EC stays the same, the plants are eating and drinking at the same rate. Yes you normally see the PH drift upwards, but as long as it stays in acceptable range it wouldn't worry me. Some nutes and ph adjusters have buffers in them to try to keep the PH in range, those could be at work. How do your plants look?

The next most likely thing to make the Ph drop is water borne microbes. Root disease tends to drop (sometimes raise) the Ph more than just a few tenths of a level tho. But anyway, how do your roots look?
 
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bigsyko75

Member
Orr thanks for dropping by and your comments which actually do make sense,i've been racking my brains to find a solution to this and that is one thing i never thought about,yes the water level does drop but not much.
Plants look fine and so do the roots they are pearly white and definately nothing wrong there,i'm using cannazym in my res aswell as my nutes to stop this kinda thing happening(root rot)
So whats happening then is like you say they are drinking and eating at the same rate,thanks makes alot of sense now.
PS by the way i gave you some rep for the helpful post.
Cheers.
 
Weedler

Weedler

Well-Known Member
I had issues getting proper PH readings I found that sticking the PH pen into the reservoir had my numbers jumping all over the place. I now use a shot glass to scoop water out of reservoir to test. This gives me a more accurate reading.

I did notice at the end of veg I was having one plant drop in PH where the other would rise. Never figured this out but thought it was due to that plant because both would do it but only on the one that was directly beneath the light. Perhaps evaporation rate was higher? My PH usually stabilizes 2 days post reservoir change
 
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bigsyko75

Member
Easy weedler thanks for dropping in,i've never stuck my EC truncheon into the res to test EC as i think the bubbles make it give a false reading,i do what you do and drain a coffee jar full from the drain tube then pour back in res,repeat the process again and pour back in res,repeat again and test that,its funny cos all 3 of my bubblers PH drop,not drastically just a point one day point next and it only started happening once i switched to 12 hour,they like to stay around 5.7 5.8 5.9 and they drift between these points.
 
W

WSRidahs

Well-Known Member
I don't think you have anything to worry about. Your ph is still in range. How many gallons are you putting in the bucket and are you topping off daily? I use 5 gallon black buckets too with 10 inch net pots and because the net pot takes up half the bucket I can only put 2 gallons in. I change my nutes every other day when in flower. When I first started to do DWC I used to change nutes every 5-7 days but I noticed a huge difference in yield when I started changing them every other day which keeps the ppm's constant. I basically change the nutes and then the next day top it off with just water and then the next day I change nutes again. My plants drink 1 gallon a day. Before I started doing this my plants would start drinking a gallon a day and then drink less and less towards the 3rd-7th day. Now my ph and ppm's are always stable. That's the difference with different size reservoirs. The bigger it is = less res changes and more stable ppm/ph. If you're using smaller net pots than me and can fit 4 gallons in the bucket, I suggest you change the nutes more frequent depending on how much your plant is drinking. When your plants feed they sometimes drink water or nutes and nutes can become toxic as the plants feed and will fluctuate ppm's and ph as it eats up all the nutes or drinks all the water. You cant really tell much from your ppm's when the nutes become toxic. If you notice your plants drinking less and less then the nutes are becoming toxic and you need a res change. Also treat every plant differently. They all feed at different rates. Another thing that can fluctuate you ph is your res temp. Keep the temps down.
 
BeaverHuntr

BeaverHuntr

Well-Known Member
WSRidahs said:
I don't think you have anything to worry about. Your ph is still in range. How many gallons are you putting in the bucket and are you topping off daily? I use 5 gallon black buckets too with 10 inch net pots and because the net pot takes up half the bucket I can only put 2 gallons in. I change my nutes every other day when in flower. When I first started to do DWC I used to change nutes every 5-7 days but I noticed a huge difference in yield when I started changing them every other day which keeps the ppm's constant. I basically change the nutes and then the next day top it off with just water and then the next day I change nutes again. My plants drink 1 gallon a day. Before I started doing this my plants would start drinking a gallon a day and then drink less and less towards the 3rd-7th day. Now my ph and ppm's are always stable. That's the difference with different size reservoirs. The bigger it is = less res changes and more stable ppm/ph. If you're using smaller net pots than me and can fit 4 gallons in the bucket, I suggest you change the nutes more frequent depending on how much your plant is drinking. When your plants feed they sometimes drink water or nutes and nutes can become toxic as the plants feed and will fluctuate ppm's and ph as it eats up all the nutes or drinks all the water. You cant really tell much from your ppm's when the nutes become toxic. If you notice your plants drinking less and less then the nutes are becoming toxic and you need a res change. Also treat every plant differently. They all feed at different rates. Another thing that can fluctuate you ph is your res temp. Keep the temps down.
Click to expand...
I been having to do the same thing.. I use 5 gallon sport coolers and I just transitioned to flower last week. I did a full res change on Friday and had to do one last night again because I top off at 4 gallons and in 5 days they drink about 3-4 gallons i set the PH at 5.8 and within 3-4 days my PH drops to 5.3 ... But yeah I have to do reservoir changes every 4-5 days.. I'm using 5.5'' net pots and doing 4 gallons in my reservoir.
 
Weedler

Weedler

Well-Known Member
WSRidahs said:
I don't think you have anything to worry about. Your ph is still in range. How many gallons are you putting in the bucket and are you topping off daily? I use 5 gallon black buckets too with 10 inch net pots and because the net pot takes up half the bucket I can only put 2 gallons in. I change my nutes every other day when in flower. When I first started to do DWC I used to change nutes every 5-7 days but I noticed a huge difference in yield when I started changing them every other day which keeps the ppm's constant. I basically change the nutes and then the next day top it off with just water and then the next day I change nutes again. My plants drink 1 gallon a day. Before I started doing this my plants would start drinking a gallon a day and then drink less and less towards the 3rd-7th day. Now my ph and ppm's are always stable. That's the difference with different size reservoirs. The bigger it is = less res changes and more stable ppm/ph. If you're using smaller net pots than me and can fit 4 gallons in the bucket, I suggest you change the nutes more frequent depending on how much your plant is drinking. When your plants feed they sometimes drink water or nutes and nutes can become toxic as the plants feed and will fluctuate ppm's and ph as it eats up all the nutes or drinks all the water. You cant really tell much from your ppm's when the nutes become toxic. If you notice your plants drinking less and less then the nutes are becoming toxic and you need a res change. Also treat every plant differently. They all feed at different rates. Another thing that can fluctuate you ph is your res temp. Keep the temps down.
Click to expand...
Well said + rep
 
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