Dailypunch21
Member
Res is 12 gallons. I use general hydro ph up , ppm is 300 and theyre drinking more water than nutes.
Why is my ph slowly dropping after few days of reservoir change?
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My Name is Mike
Well-Known Member
That, lockout or plant is drinking more fighting high temps/humidity..
OP what are the environment temps/RH? What is rez temp?
Dailypunch21
Member
Res temp is 65 room is 75 and humidity is 60 during the day 40 at night
a senile fungus
Well-Known Member
I'm no expert, remember that, just a dude with a few grows under his belt.
If they're drinking more water than nutes, then as the res level lowers the remaining solution will drop pH and the EC will go up.
If they're taking in more nutes than water, then as the res level falls then the solution will raise in pH and the EC will drop.
If it's in balance, the solution won't drift very far in either direction as the level drops, which isn't necessarily ideal because a swing in pH is good for a variety of nutrient uptake at various pH range
I ran a sterile res, nothing but GH 3 part and water. When I was running hydro I had to find near that balance point, and when I did it was set it and forget it.
I only changed the res once when I flipped to flower, not every week like the OP. I would top off the res with water (I had a fill-line), which dilutes the solution. I premeixed the nutes in a bottle, and would titrate them in until I reached the desired EC, then I would adjust pH if necessary, super easy.
Dailypunch21
Member
I have a auto top of that just has RO water and uc roots in it.
Agreeing Thumb
Member
Complete noob in hydro, and i'm pretty sure this has been seen.But here it is
Dailypunch21
Member
When I do a res change the ph will rise for the first few days but as the ph rises above 6.5 I correct it. After 3 or 4 days is when the ph will start dropping. The plant is drinking a lot of water just eating really slow. Ppm is at 270 should I continue to lower? Btw this plant is 5x5 it’s pretty big
Dailypunch21
Member
anyone think it might be a nutrient lockout? I just changed my res and have 80 ppm but ph is still dropping and ppm is staying steady. Would nutrient lockout have anything to do with ph dropping?
fridayfishfry
Well-Known Member
Are you taking care of your ph meter? Is it a good one?
This here is a good one
Using ph up/down and or poor maintenance can mess with a ph pen probe
This here is a good one
Using ph up/down and or poor maintenance can mess with a ph pen probe
a senile fungus
Well-Known Member
How does the plant look? Do the pH swings seem to be causing any problems?
Dailypunch21
Member
I use a pen meter and also double check with the ph test kit. The plant looks great just very slow growth and she isn’t eating but still drinking a lot of water. I have a 1000 watt hps and I am in flower and don’t see much growth at all. I have always heard of the ph drops something is wrong in the root zone but I’m not sure what else I can do at this point
Dailypunch21
Member
Vader og, oceangrown genetics, solved my problem. I was getting to much air into the system. I removed a air stone and one of the air pumps and within 15 min ph began to rise and plant is eating. Thought I would share this with everyone so if anyone else runs into the problem they’ll be able to try this to fix it! Cheers guys
OldMedUser
Well-Known Member
I find that very strange. I've been doing DWC for almost 20 years and never ran into air volume having any effect on pH. For years I used a small air pump with a 12" stone in Rubbermaid tubs then got larger pumps and went to two stones. I would set my pH at around 5.5 and over three days it would rise to 6.2 or so and I'd knock it down to 5.5 again with conc. sulfuric acid. Then I got pH Perfect nutes and retired my pH pen.
OldMedUser
Well-Known Member
Nutrient lockouts usually happen when the pH is too far out of range and mainly affects micronutrients that cause problems with new growth.
fridayfishfry
Well-Known Member
i was thinking if he was using CO2 but that would lower pHI find that very strange. I've been doing DWC for almost 20 years and never ran into air volume having any effect on pH. For years I used a small air pump with a 12" stone in Rubbermaid tubs then got larger pumps and went to two stones. I would set my pH at around 5.5 and over three days it would rise to 6.2 or so and I'd knock it down to 5.5 again with conc. sulfuric acid. Then I got pH Perfect nutes and retired my pH pen.
i've never had my pH rise unless I added tap water
OldMedUser
Well-Known Member
I never used anything but distilled or RO water but tap water often rises even after dropping with pH down due to unreacted carbonates in the water. My tap water comes from a dugout on my property and is around pH 8 and 400+ppm so it's crap.
My procedure was to top up the water then allow to mix for an hour or so then test pH and ppm. The ppm was always lower and the pH was always higher. Then I would add small amounts of nutes to raise it back up to my target ppm and add a few drops of acid to bring down the pH. If it went to low I'd just leave it and it would get back up to the mid 5s by the next day. Never seemed to go over 6.3 so that must be the buffer level of the older AN nutes. Started using the pH Perfect ones a few years ago and never worry about pH now. RO or distilled water has no effect on pH as both are neutral. They just take on the pH of whatever is added to them.
Takes a lot of CO2 to make the pH go down and the acid that is formed doesn't stay acid for all that long. Putting pure CO2 through the stone will screw things up tho. A poster years back figured the plants would do great with added CO2 to his DWC as it worked in the air. No amount of logic could convince him otherwise and he killed his 8 plant RDWC in a week. Never saw him in that forum after that. Think he joined a monastery or something.
fridayfishfry
Well-Known Member
I have an idea rattling around about bottled O2 bubbles for hydroponic solution. I'm yet to get an answer. I do know that if it were to be done it'd have to be in an unoccupied building with a fire suppression system. I have my suspicions that old-timer commercial growers did this from the photo results which are insane compared to just near-perfect environment and CO2.
I see marketing for hydrolysis "oxygenation". they taught me in chem to not breathe hydrolysis specifically with ionic solutions involved
I see marketing for hydrolysis "oxygenation". they taught me in chem to not breathe hydrolysis specifically with ionic solutions involved
OldMedUser
Well-Known Member
Why?
fridayfishfry
Well-Known Member
bottled oxygen will allow for fast explosive combustion. If you have oxygen tanks for acetylene cutting and you're doing it inside there are regulations. regulations unlike cannabis laws. One example is a little oil was accidentally in a oxygen tank flow regulator which acted as fuel and caused an explosion which killed the guy. that's the construction way, not sure how the hospitals do their thing.