Need Advice on the pH swing from Well Water

[GR33NL3AF]

I want to set up an irrigation system however when my reservoir is left alone for even a day the pH will raise from 5.5 to 7.5-8. I do not run recirculating, I simply fill my 50 gallon drum when I need to water, add nutes, pH and feed. I am going to experiment this week by filling a res, and ph'ing it twice over 3 days, to see if the water will inevitably stabilize.

Will an R/O filter eliminate this issue?
Is the high silica content in my well water most likely causing this?

Thanks,

GL

 

[Jalisco Kid]

If you are saying it comes out of the well at 5.5 pH then I would say you have something live in your barrel. It should be stabilized underground. JK

 

[ttystikk]

Keep your reservoir water totally in the dark, covered with a lid. To kill what's in it add h2o2, then test it one you've done this. If pH rises, it may be outgassing something. If you have an analysis of your well water, study it carefully to see if you can add everything but what your water is already rich in, and thus compensate. RO is an oft used solution, but it isn't always necessary. Hydro stores will sell anything to make a buck- care to guess how many RO systems I've seen in my city- where the tapwater flows at EC .05?! Seriously!

 

[Seamaiden]

I want to set up an irrigation system however when my reservoir is left alone for even a day the pH will raise from 5.5 to 7.5-8. I do not run recirculating, I simply fill my 50 gallon drum when I need to water, add nutes, pH and feed. I am going to experiment this week by filling a res, and ph'ing it twice over 3 days, to see if the water will inevitably stabilize.

Will an R/O filter eliminate this issue?
Is the high silica content in my well water most likely causing this?

Thanks,

GL

Yes, an RO will absolutely eliminate this issue. You don't say what the pH is coming out of the tap, but I'm going to guess that it's somewhat alkaline, and depending on your location it's probably due to carbonate hardness (think calcium or magnesium carbonates, or as dolomite lime, calcium magnesium carbonate), or bicarbonate hardness. Alkalinity is defined as resistance to pH shift, and so when you force it down, it's going to bounce back up unless you use sufficient acid to neutralize the carbonate molecules present in the water.

What form is the silica? To the best of my understanding, it doesn't have a huge effect on pH or alkalinity. That could simply mean my understanding is limited, but with regard to alkaline water, my experience has always been that it's due to carbonate/bicarbonate hardness. (Some decades in the aquatic ornamental industry.)

You could also filter through peat moss, but that could be a huge pain in the ass, though nowhere nearly as wasteful as reverse osmosis. I keep intending to make myself a giant peat moss filter to see what happens, but I get distracted with other things. Filtration through peat was how I used to set up filtration for the very delicate South American fishes from the Amazon and Rio Negro regions, it was the best way to soften and acidify the water column for them, gentlest as well. It does stain the water, but who cares about that when it's going into roots? Aquarists have a different opinion on water color and clarity, of course.

 

[obsoul33t]

i have run the peatmoss filter , it works well when the peat is newer but peat will in a short time stop neutralizing alkalinity .
i have been experimenting with citric acid to deal with bicarbs and so far it seems to work well . citric acid does some trippy stuff
for instance
well water starting at 222mg/l alkalinity, ph 7.0
ph down with citric acid to 6.0 cuts the measurable alkalinity in half
as the water sits the ph slowly rises back up to 6.5 but the alkalinity does not rise so it seems as if once bicarbonates have been neutralized they are done causing hardness in the water .
now once water is mixed with nutrients and the ph adjusted down to proper levels using citric acid it stays where it is adjusted too and won't rise .

grab some citric acid and measure your ppm/ec then add citric acid to bring the ph down and watch as the ppm/ec drop , it takes extremely little citric acid to adjust your water .. add your nutes then readjust ph with more citric acid ..

 

[obsoul33t]

forgot to mention if you use citric acid to bring the ph below 4.5 it completely neutralizes alkalinity . having no alkalinity is not a good idea so if you ph an amount of alkaline water down to 4.5 to neutralizes and then add back plain tap to can find a sweet spot of alkalinity around 20-60 mg/l .... having a bit of alkalinity will buffer your media from ph swings ..

cheers

 

[GR33NL3AF]

If you are saying it comes out of the well at 5.5 pH then I would say you have something live in your barrel. It should be stabilized underground. JK

Keep your reservoir water totally in the dark, covered with a lid. To kill what's in it add h2o2, then test it one you've done this. If pH rises, it may be outgassing something. If you have an analysis of your well water, study it carefully to see if you can add everything but what your water is already rich in, and thus compensate. RO is an oft used solution, but it isn't always necessary. Hydro stores will sell anything to make a buck- care to guess how many RO systems I've seen in my city- where the tapwater flows at EC .05?! Seriously!

Yes, an RO will absolutely eliminate this issue. You don't say what the pH is coming out of the tap, but I'm going to guess that it's somewhat alkaline, and depending on your location it's probably due to carbonate hardness (think calcium or magnesium carbonates, or as dolomite lime, calcium magnesium carbonate), or bicarbonate hardness. Alkalinity is defined as resistance to pH shift, and so when you force it down, it's going to bounce back up unless you use sufficient acid to neutralize the carbonate molecules present in the water.

What form is the silica? To the best of my understanding, it doesn't have a huge effect on pH or alkalinity. That could simply mean my understanding is limited, but with regard to alkaline water, my experience has always been that it's due to carbonate/bicarbonate hardness. (Some decades in the aquatic ornamental industry.)

You could also filter through peat moss, but that could be a huge pain in the ass, though nowhere nearly as wasteful as reverse osmosis. I keep intending to make myself a giant peat moss filter to see what happens, but I get distracted with other things. Filtration through peat was how I used to set up filtration for the very delicate South American fishes from the Amazon and Rio Negro regions, it was the best way to soften and acidify the water column for them, gentlest as well. It does stain the water, but who cares about that when it's going into roots? Aquarists have a different opinion on water color and clarity, of course.

forgot to mention if you use citric acid to bring the ph below 4.5 it completely neutralizes alkalinity . having no alkalinity is not a good idea so if you ph an amount of alkaline water down to 4.5 to neutralizes and then add back plain tap to can find a sweet spot of alkalinity around 20-60 mg/l .... having a bit of alkalinity will buffer your media from ph swings ..

cheers

Sorry I didn't elaborate on the actual numbers, pH coming in is around 5.3-5.5, this is after the water softner and TALL BOY fixed with a carbon filter. I add my nutes, which hardly effects that number and use an organic pH up from Nectar for The Gods, which is a liquid calcium, bringing the number to around 5.7-5.9. If I have leftovers, I leave it until next feed, this is when I notice the swing. 1-2 days later that same res will read 7.5-8.0. At this time I do use Earth Juice's pH down which is Citric Acid.

A long time ago when I setup the water lines for this unit I ran simple sch. 40 (3/4") PVC around the foundation of the house. During an alteration, inside the house, I noticed a green residue in the pipe (thinking algae). Never thought much of it, seeing is how I was growing in Peat and frequently using bennies. Over the next couple days I am going to cover the PVC entirely and look into flushing the lines to sterilize. I will also experiment with citric acid as you mentioned OBS. If these don't work I'll buy an R/O, I do have a 300gal. res. I can use to store water.

Thanks for the help farmer's!

GL

 

[ttystikk]

Before going to all the expense, just buy a res tub you can keep your well water in for a few days before use. Drop an airstone in there to help it outgas whatever is in it, and then it should remain stable for you. Chasing pH is a great way to screw up your nutrient balance, as well as causing fragile chelates- like iron- to precipitate out of solution.

 

[GR33NL3AF]

Before going to all the expense, just buy a res tub you can keep your well water in for a few days before use. Drop an airstone in there to help it outgas whatever is in it, and then it should remain stable for you. Chasing pH is a great way to screw up your nutrient balance, as well as causing fragile chelates- like iron- to precipitate out of solution.

I'm wondering now if this is the reason for my high pH runoff... I've seen 6.6-7.0 runoff from consistent 5.7 feedings. If I setup a 'hub' like your saying I think I can fix this.

Here is what I did today:
Let the water run through my filters for 2-3 minutes to push out all the crap that sat in the lines. I then filled two sterile 5 gallon buckets up and put a clean submersible pump in each for circulation. I set one in a common area that is constantly lit and the other in a back room that is pitch black. Here were my initial readings:
5gal in light - starting pH 4.8 and water temp was 68F
5gal in dark - starting pH 4.7 and water temp was 66F

1 Hr later....

5gal in light - pH 5.2 - temp 76F
5gal in dark - pH 5.1 - temp 73F

These readings lead me to believe it is out gassing which is causing the spike in pH

I will check them again Thursday (10/24). If pH has skyrocketed I will use citric acid to bring it down to 6.0 and leave for another day or two...

 

[ttystikk]

Gotta love it when a guess comes together!

 

[obsoul33t]

i would bypass the water softner

 

[GR33NL3AF]

i would bypass the water softner

Interesting...
About a year ago when I was running ebb n flow with RW and mixing 100+ gallon res' with synthetics the softner gave out and I had serious fallout which I attributed to the excessive silica coming through.

 

[GR33NL3AF]

Gotta love it when a guess comes together!

Don't think I mentioned that my ppm readings on a full res of fresh water was 0

 

[ttystikk]

Don't think I mentioned that my ppm readings on a full res of fresh water was 0

I would find that a bit suspect without some further testing, but it if true then it's excellent news; it's telling you that once the outgassing process is complete that there isn't anything left in the water to affect pH so balancing it should be easy using only small quantities of pH up or down.

 

[Seamaiden]

Don't think I mentioned that my ppm readings on a full res of fresh water was 0

JUST from the filtration you mentioned? If so, sweet, I envy you because I hate the waste generated using RO. By the same token, that also means that said water of yours has zero alkalinity, which means it has zero resistance to pH shift.

Btw, O2 drives pH up, and CO2 drives it down, in a water column. Freshwater planted tank enthusiasts use CO2 dosing to keep the water pH in their aquaria driven downward.

 

[GR33NL3AF]

JUST from the filtration you mentioned? If so, sweet, I envy you because I hate the waste generated using RO. By the same token, that also means that said water of yours has zero alkalinity, which means it has zero resistance to pH shift.

Btw, O2 drives pH up, and CO2 drives it down, in a water column. Freshwater planted tank enthusiasts use CO2 dosing to keep the water pH in their aquaria driven downward.

Yea, saw 0 straight from the Tall Boys. Will be running multiple tests today and report back. I really feel R/O is the answer. As I mentioned elsewhere, my runoff is always high even though I constantly feed under 6.0 I see 6.6-7.0. I am thinking because I am not stabilizing the pH pre-watering it's shifting in the soil.

I run my air pump IN the room which is generally pumped with 1000ppms of CO2 so I would imagine that is what my airstones are pumping into my res.

Is 76F an unsafe water temp for my res'? I do have 3 large air stones and usually leave a small pump for circulating. Thinking about wrapping the res in relfectix or moving into another room.

 

[Seamaiden]

I'd be concerned it's a little warm, but then I don't do undercurrent or anything like that. I am a fish woman.

It's odd, but I would think that if you're pumping air that's higher in CO2 that you'd concurrently be seeing lower pH levels in the reservoir. I mean, people running reef systems in winter have seen the whole thing crash because their homes have just that much more CO2 in the air that it causes Ca to not be taken up, the kalkwasser can't keep it stabilized, just all kinda fucked up. Many have to move their sumps, etc, into the basement or even outside the home because the water column ends up too high in CO2 for the corals and other hermatypics to take up and utilize calcium.

 

[GR33NL3AF]

I'd be concerned it's a little warm, but then I don't do undercurrent or anything like that. I am a fish woman.

It's odd, but I would think that if you're pumping air that's higher in CO2 that you'd concurrently be seeing lower pH levels in the reservoir. I mean, people running reef systems in winter have seen the whole thing crash because their homes have just that much more CO2 in the air that it causes Ca to not be taken up, the kalkwasser can't keep it stabilized, just all kinda fucked up. Many have to move their sumps, etc, into the basement or even outside the home because the water column ends up too high in CO2 for the corals and other hermatypics to take up and utilize calcium.

Next test I will suck air from under the house for my air pump... That's pretty crazy.

 

[squiggly]

it seems as if once bicarbonates have been neutralized they are done causing hardness in the water .

That is correct. The reaction here is:
HCO3- + H+ -------> H2CO3 ---- rapid decomposition----> H2O + CO2

H2CO3 is extraordinarily unstable and rapidly decomposes to neutral species. In fact this represents the bottom of a thermodynamic "well". The neutralization between HCO3- and H+ is actually not very favored--the stability of the decomposition products actually drives the reaction forward via entropic effects.

 

[squiggly]

Here's a diagram which illustrates the point:

Often times stability of products vs reactants can have an effect on the activation energy of a process analogous to that of a catalyst (ie lowering Ea). What you would notice, for instance, is that the activation energy for neutralization would actually be higher in a solution which was saturated with CO2 gas (because the decomposed neutral products would be less favored under these conditions). In a solution with virtually no CO2 the decomposition will take place on the femto->picosecond scale. Because the decomposition is so favored it actually "drags" the rest of the reaction with it.

Some reactions begin with reactants at a lower energy state and progress to a higher energy state, these are not typically spontaneous reactions and they require energy input (like electrolysis of water for instance).

Reactions which go "down" in energy both release energy as a result, and are spontaneous.