PH dropping very fast....PPM drops a lil

[themlouds]

Good morning!
I have run into a minor issue that I can't seem to pinpoint at the moment. I am running a 16 site (13 gallon buckets) undercurrent DWC system with 2" PVC pipe. I have everything environmentally dialed in and I have plenty of air going to the buckets (2 Air Force Pro 80's). Water temp is around 66-68 at most. Room temp is 65-82 degrees at the warmest. I have been running this same system for years with no issues until now. When the system is filled with water, there is about 170 gallons recirculating. I am running the entire AN ph perfect line but Im in Veg right now so I am only using their 3 part and B52. I am using about 800ml of Grow Micro Bloom and 400 ml of B52 into my system to get a reading of 6.1ph 930 PPM (.7 conversion). 2 days later my reading will be 4.8 ph 910 PPM and my water level will be a little less than when I filled but not much less. Its done this for 4 straight weeks. Ive flushed a 1000 times but same thing after 2 days. My plants seem to be growing slower than usual and I am wondering if Im underfeeding them (just started a new strain and Im still learning it. All plants in system are same strain) or am I having another problem? 5 weeks ago my Mini Split stopped working and I didn't catch it for a few days and I did get some rot at the root level. I been there before so I did what I normally do (H2O2 for a few days) and the girls bounced back like normal. Roots are primarily healthy now except for some of the older roots that were destroyed by the rotting. I am tired of ph up and ph up and ph up as I am seeing minimal growth. My girls look healthy for the most part just not moving along as fast as I would like. What is causing this? Most things I read say root issues but thats not it and some say nutes could be too high but that can't be it either cause Im feeding on the low side of things already. Help!

 

[themlouds]

I am using R/O water as well. When I flush, I use chlorine filtered water. Tap water doesn't see the system at all.

 

[makka]

this really helped me a while ago its not mine and its off another forum but imo all holds true init for me anyway

This table is not meant to be exhaustive. It is primarily for use in conjunction with DWC & variants or any other hydro setup where you have an air stone. The main complication is the acid rain effect in Note 1 below. This does not apply to waterfall effect or flooming for introducing Dissolved Oxygen.
Its intention is to give anyone suffering ph, EC issues in DWC and variants some idea of the different solutions to the various states you can have.
There are 18 different states you can get in DWC and though many have common solutions, such as a falling EC, which is usually a good sign could mean a slight raise in EC may be needed. However, this depends on the state of the other elements. For example, if our falling EC is accompanied by a falling ph too, this suggests a res change due to either acidic nutrients or ph- or the acid rain effect (note 1) causing the ph to drop.
The first thing to check in any of these scenario's is the meters being used.
Make sure they are calibrated. If you can, check the readings against a second meter if things dont improve after making changes.
As a general guide, if the ph is between 5.8 and 6.2, do not rush into changing anything unless your plants are displaying symptoms of a problem.

In DWC, a good safe EC is around 1.2 to 1.4, I have rarely seen problems with plants fed at this level.
These levels are for healthy maturing plants either just before placing in flower or once into flower. For smaller/younger plants adjust EC accordingly, starting down at around 0.4
This is exclusive of any background EC. So if your source water has an EC of something like 0.5, work with an EC of 1.7 overall. As always, use judgement in finding the correct EC for your plants. This will vary by plant depending on the stage of growth. DO NOT jump in with seedlings of freshly rooted clones with an EC of 1.7, you will kill your plants.

I am also assuming grow media have been washed/rinsed/buffered properly in ph'd water.
Most media (inert) should be soaked in water with a ph of around 5.8 for 24 hours. This tends to help prevent later ph fluctuations.
Water level EC pH Solution
Static Static Static Plant not feeding/drinking, change EC, check meters. Usually, lowering the EC a little should get the plant feeding again
Static Static Rising Ph buffers probably raising ph. This is usual. Having a static water level is not though, so again, a slight reduction in EC or a res change should resolve this.
Static Static Falling Usual cause of this is when media has been rinsed at a lower ph than you require.
The other possibility is that too much CO2 has been pumped into the water. See Note 1.
Change your res and look at the volume of air pumped plus look at your air source.
Static Rising Static Plant is leeching nutrition, raise EC. Note 2
Static Rising Rising Plant leeching nutrition, Raise EC. An unusual state. The rising ph is probably caused by what nutrient leeching back.
If these are alkaline, it will lead to the rise in ph. Could also be ph buffers.
Static Rising Falling As above but be aware of the acid rain effect mentioned in note 1. Res change, plus increase in EC.
Static Falling Static Plant eating but not drinking. Not ideal. Lower EC or res change
Static Falling Rising As above but rising ph is a better sign. Lower EC slightly or res change.
Static Falling Falling Falling ph along with falling EC but no drop in water level suggests a res change. Could also be an acid rain effect as per note 1. Depending on other symptoms, lowering EC after res change.
Falling Static Static Perfect conditions. EC and ph are at the correct level.
Falling Static Rising Normal state most people encounter. Nothing to worry about, carry on doing what you are doing unless other plant symptoms.
Falling Static Falling Res change plus a change of EC. Lower EC if over 1.4, raise EC if lower than 1.0
Falling Rising Static Plant is drinking more than eating, lower EC.
Falling Rising Rising Plant is drinking more than eating, lower EC
Falling Rising Falling Plant is drinking more than eating, lower EC. Also, res change due to possible acid rain problem.
Falling Falling Static Hungry plant, raise EC. Very good situation to be in. Nute buffers are working and plant is taking a balance of nutrients.
Falling Falling Rising Almost as above, usually considered almost perfect, raise EC slightly.
Falling Falling Falling Res change. Potential acid rain issue but plant is still eating & drinking. Raise EC on new res.

The ideal scenario you are looking to achieve is where the EC is either dropping slightly or remaining static, with a static or slightly rising ph and a dropping water level. If you get this situation, keep doing exactly what you are doing because your plant is feeding and drinking.
Even a moderate plant that will be yielding 3 or 4 oz should be going through 3 or 4 l of water per day. I have seen me giving larger plants as much as 10l per day food & water, its like keeping a horse! But you cant smoke a horse

Note 1.
When pumping air into a nutrient solution in order to add Dissolved Oxygen, not only oxygen is present, CO2 is also pumped in. If you live near a busy road, this may be higher than normal, so you may get a dropping ph quite often. I have noticed most of the growers who suffer from a falling ph in DWC tend to live in large cities. This may not be a link but it could be.
When CO2 is added to water, it makes it more acidic. This is the precise process which causes acid rain, pollution from power stations etc pouring CO2 into the air, this mixes with the water vapour in clouds causing acid rain.

Note 2.
Most people assume that with a rising EC, it is the plants way of saying, I dont want more food, here, have some back.
What is actually happening is this.
Plants roots take in water/nutrients through a process called Osmosis. Effectively, if you think in terms of the roots having their own internal EC.
The osmosis process will always try to balance out the EC's, taking from the higher side of the barrier and giving to the lower part.
So if the EC of the nutrient solution is higher than the "internal EC", then food & water will flow from the solution to the roots, this is the normal process.
If however, the EC of the solution is higher than the "internal EC", then the balancing will work the other way and nutrition will be leeched from the roots to the solution.
A res change or increase in EC should resolve depending on the other factors such as ph and water levels.

Note 3.
Nutrients flow around a well hydrated plant much more effectively and faster than one which isnt as well hydrated.
How can growers use this?
By feeding at lower levels, the plant needs to take on more water in order to get the nutrition it requires.
So by feeding at moderate levels, this forces the plant to drink more.
By drinking more, it is better hydrated, because it is better hydrated, it needs more food, making it eat more.
So feed at moderate levels rather than overly aggressive levels.
The method of pushing the EC until you see signs of nute burn is damaging to the plants and although many growers use this method, I am not a fan though your plants are not mine!

 

[churchhaze]

Add some potassium hydroxide.

 

[churchhaze]

For smaller/younger plants adjust EC accordingly, starting down at around 0.4

0.4EC will lead to early deficiency, which is not optimal. Just start with 1.2-1.4 as soon as there's roots. (immediately for seedlings). You will get better results. The idea that "full strength" will burn seedlings is ridiculous. Nobody plants seeds in infertile soil only to fertilize it later. For soil, you're supposed to build a nutrient rich soil from the get go.

This is exclusive of any background EC. So if your source water has an EC of something like 0.5, work with an EC of 1.7 overall. As always, use judgement in finding the correct EC for your plants. This will vary by plant depending on the stage of growth. DO NOT jump in with seedlings of freshly rooted clones with an EC of 1.7, you will kill your plants.

So the stuff in your water shouldn't be counted? If you actually had an EC of 0.5, it's more than likely that all that is calcium carbonate. If your tap has an EC of 0.5, raise it to 1.4, not 1.7. The only time this wouldn't be true is if you're forced to use a water softener (apartment), which in that case you have no other option but RO because of the toxic levels of sodium.

I'm not sure how ANY of that answers the OP's question.

 

[makka]

0.4EC will lead to early deficiency, which is not optimal. Just start with 1.2-1.4 as soon as there's roots. (immediately for seedlings). You will get better results. The idea that "full strength" will burn seedlings is ridiculous. Nobody plants seeds in infertile soil only to fertilize it later. For soil, you're supposed to build a nutrient rich soil from the get go.



So the stuff in your water shouldn't be counted? If you actually had an EC of 0.5, it's more than likely that all that is calcium carbonate. If your tap has an EC of 0.5, raise it to 1.4, not 1.7. The only time this wouldn't be true is if you're forced to use a water softener (apartment), which in that case you have no other option but RO because of the toxic levels of sodium.

I'm not sure how ANY of that answers the OP's question.

not looking for an argument lol it works for me

 

[HempletonState]

Good morning!
I have run into a minor issue that I can't seem to pinpoint at the moment. I am running a 16 site (13 gallon buckets) undercurrent DWC system with 2" PVC pipe. I have everything environmentally dialed in and I have plenty of air going to the buckets (2 Air Force Pro 80's). Water temp is around 66-68 at most. Room temp is 65-82 degrees at the warmest. I have been running this same system for years with no issues until now. When the system is filled with water, there is about 170 gallons recirculating. I am running the entire AN ph perfect line but Im in Veg right now so I am only using their 3 part and B52. I am using about 800ml of Grow Micro Bloom and 400 ml of B52 into my system to get a reading of 6.1ph 930 PPM (.7 conversion). 2 days later my reading will be 4.8 ph 910 PPM and my water level will be a little less than when I filled but not much less. Its done this for 4 straight weeks. Ive flushed a 1000 times but same thing after 2 days. My plants seem to be growing slower than usual and I am wondering if Im underfeeding them (just started a new strain and Im still learning it. All plants in system are same strain) or am I having another problem? 5 weeks ago my Mini Split stopped working and I didn't catch it for a few days and I did get some rot at the root level. I been there before so I did what I normally do (H2O2 for a few days) and the girls bounced back like normal. Roots are primarily healthy now except for some of the older roots that were destroyed by the rotting. I am tired of ph up and ph up and ph up as I am seeing minimal growth. My girls look healthy for the most part just not moving along as fast as I would like. What is causing this? Most things I read say root issues but thats not it and some say nutes could be too high but that can't be it either cause Im feeding on the low side of things already. Help!

I run a very similar setup with a chiller and RO water. House and Garden came out with an RO stabilizer that you add to the water an hour before you add notes and your ph will not fluctuate I have been using it for about a year now and it works flawlessly

 

[ttystikk]

You never said how big your plants are or how much they drink every day.

 

[HempletonState]

You never said how big your plants are or how much they drink every day.

Is this for me of him?

 

[ttystikk]

Is this for me of him?

The OP.

Really though, when I notice pH dropping fast, I just take it as a sign they're running out of something and so I either do a top up or completely drain and refill with fresh nutrient solution. I've found that the smaller the nutrient reservoir the plant has access to, the shorter these intervals are.

 

[HempletonState]

The OP.

Really though, when I notice pH dropping fast, I just take it as a sign they're running out of something and so I either do a top up or completely drain and refill with fresh nutrient solution. I've found that the smaller the nutrient reservoir the plant has access to, the shorter these intervals are.

I agree I had noticed when I went to 13 gallon buckets with 2" lines back to the controller that it would take at least a day for the water to keep circulating though the system for the ph to stabilize. Would set it up at 5.8 and without fail the next day it would be up to 6.5 then I would bring it down and it would be fine for the rest of the week. Have always thought it was th system because when I ran the drip ring system in 5 gallon buckets I didn't experience it

 

[Mr Roboto]

if the ph is rising it usually just means your plants are eating and doing fine, if its dropping thats usually means the plants aren't eating as much usually caused by root rot or pythium.........well usually