Rain water and tap water discussion

[Creeperpark]

Common chemicals big water treatment systems use are sodium hypochlorite and sodium bisulfite.
Sodium hypochlorite is a clear, slightly yellowish solution with a characteristic odor. As a bleaching agent, it is usually a 5 percent sodium hypochlorite with a pH of about 11. More concentrated solutions (10 to 15 percent) have a pH of about 13.

Sodium Bisulfite pH is 3.6 to 4.6 used to lower the pH of outgoing water. This water treatment method is used to cancel the cation exchange capaticy.

 

[Creeperpark]

When these chemicals are used the water will not be the same as natural water. I only use pure water for growing all plants. If you have plants that are living on tap water your plants are not loving at their full potential.

Very important note: You can't change waters in the middle of a grow without causing problems. When changing waters one has to do it slowly and gently. Start with 75% old water to 25%new water for a week, then 50 50 for a week before switching all the way. .

 

[f-e]

Dam that's harsh even in our city's over here we don't get higher than 200 ppm

You guys are sat on granite. Same as Canada as you look across. From north of the Humber, down to Nottingham, it's sand stone. Over 300 is common. On the west coast, wales is soft as it just fell, and the rocks harder. That is piped to much of the black country. While Stoke (the potteries) is clay so quite hard. Norfolk and east anglia remain hard, and as we get to Dover it's just chalk. The hardest water in the UK.

I have almost 300ppm as calcium carbonate. Total hardness pushing 350. That's in Robin Hood country

 

[flylowgethigh]

I use tap, which comes from a well in a limestone system. I have a particle filter, then a carbon filter. This seems to work OK. I have to add about a tsp of pH down per each 4 gallon carboy, and a spilling cap full of cal-mag.

Tap water from a bath tub close to the grow room is convenient in all weather, day and night. Move 4 gallons at a time in a car-boy to the 12 gallon reservoir.

I pH the water after I add to the reservoir, and later that day the pH will have risen a few 0.1's up. I bubble air through the water, and I suspect there is a reaction with the air (maybe Co2?) as O2 is dissolved. I have to add pH down maybe twice until things settle.

 

[Three Berries]

With my well water at 7.4 and I add the nutes the pH comes in close to 6.6-7.7. But it takes a day to really settle out. You can watch the carbonation bubbles as the CO2 is released from the reaction.

The Potassium Bicarbonate I am now using takes about a teaspoon to raise the pH 0.1

 

[flylowgethigh]

I want to try some lemon juice to drop the pH number. I have made alkaline biased soil(pH well over 7), and like the water to be around 6.3ish. I am trying to get the CEC up and ions moving.

 

[Petrochemical]

I don't know I think my relatives when I was growing up thought it would be cute to make me work I'm sure nowadays with how parents candle kids they would have seen the work that I had to do was indentured servitude laughing out loud that being said there's something I've noticed in all of the big properties that had really successful Gardens and really successful cultivars, I mean it just makes sense that if it's going to pour off your house that you have a big blue catch Basin to catch all that rain water as long as there's not anything contaminating it. anything I've ever seen this ever been in any kind of water with the exception of chloramines and stuff like that would just gas off over 24 48-72 hours so I think it's a good idea and a good suggestion for anyone to collect rainwater and use it ,it just makes sense.I mean unless you have the water get contaminated you should be good to go unless you're in like Shanghai China

 

[Three Berries]

I want to try some lemon juice to drop the pH number. I have made alkaline biased soil(pH well over 7), and like the water to be around 6.3ish. I am trying to get the CEC up and ions moving.

Citric acid is pretty cheap and has many uses. Great rust and scale dissolver and water softener resin tank cleaner. It's what they add to water softener salt for the cleaner. And when they say lemon juice in cooking it's really the bitterness from the citric acid they are after usually.

And I found out using a XOH base for pH up will strip the calcium out of the mix. I was using KOH and you could see it drop the Calcium out as CaOH instantly.

I don't know if I could have made any more mistakes in the last two years but I'm glad to hopefully have them over with......

 

[VerdantGreen]

rainwater for me, where i live it is pretty clean and the tapwater has lime added to 'improve the drinking quality'.

but more than that, as a gardener by trade i get to see the difference it makes there too. in a dry spring when you have to water with a hose it just isn't the same as rain. rain makes plants grow better than anything else ime.

VG

 

[flylowgethigh]

I think rain has a little H2O2, at least when it is fresh. That stuff is supposed to be good for plants.

The water in the underground limestone caverns here doesn't get Oxygen. I think having Oxygen in the water is probably good, so I bubble my reservoir with a fish tank bubbler.

I just flashed on the thought that the extra O+ ion from H2O2 may be a good thing down there in the root zone, and that may be why it is rumored that H2O2 is good for gardens.

 

[Three Berries]

Mechanisms of hydrogen peroxide decomposition in soils​

The rates and mechanisms of hydrogen peroxide (H2O2) decomposition were examined in a series of soil suspensions at H2O2 concentrations comparable to those found in rainwaters. The formation of hydroxyl radical (OH) as a possible decomposition intermediate was investigated using a new, highly sensitive method. In surface soils with higher organic matter or manganese content, H2O2 usually decayed rapidly, with disproportionation to water and dioxygen dominating the decomposition, whereas the formation of the hydroxyl radical (OH) represented <10% of the total H2O2 decomposed. In contrast, for soils with lower organic matter content, H2O2 usually decayed much more slowly, but OH was a major product of the H2O2 decomposed. The decomposition was principally associated with soil particles, not the soil supernatant. Different sterilization techniques indicated that decomposition of H2O2 was at least partly due to biological activity. Because the loss of H2O2 can largely be accommodated by the production of O2 and OH within these soils, our results suggest that disproportionation through a catalase-type mechanism and the production of OH through a Haber-Weiss mechanism represent the principal routes through which H2O2 is lost.

Mechanisms of hydrogen peroxide decomposition in soils - PubMed

The rates and mechanisms of hydrogen peroxide (H2O2) decomposition were examined in a series of soil suspensions at H2O2 concentrations comparable to those found in rainwaters. The formation of hydroxyl radical (OH) as a possible decomposition intermediate was investigated using a new, highly...

pubmed.ncbi.nlm.nih.gov

The OH radical will strip calcium. and form insoluble CaOH.

Here's a pic of 2L of well water that I pHed with KOH. It striped the Ca out immediately and you can see it settle in the bottom.

 

[Creeperpark]

Mechanisms of hydrogen peroxide decomposition in soils​

The rates and mechanisms of hydrogen peroxide (H2O2) decomposition were examined in a series of soil suspensions at H2O2 concentrations comparable to those found in rainwaters. The formation of hydroxyl radical (OH) as a possible decomposition intermediate was investigated using a new, highly sensitive method. In surface soils with higher organic matter or manganese content, H2O2 usually decayed rapidly, with disproportionation to water and dioxygen dominating the decomposition, whereas the formation of the hydroxyl radical (OH) represented <10% of the total H2O2 decomposed. In contrast, for soils with lower organic matter content, H2O2 usually decayed much more slowly, but OH was a major product of the H2O2 decomposed. The decomposition was principally associated with soil particles, not the soil supernatant. Different sterilization techniques indicated that decomposition of H2O2 was at least partly due to biological activity. Because the loss of H2O2 can largely be accommodated by the production of O2 and OH within these soils, our results suggest that disproportionation through a catalase-type mechanism and the production of OH through a Haber-Weiss mechanism represent the principal routes through which H2O2 is lost.

Mechanisms of hydrogen peroxide decomposition in soils - PubMed

The rates and mechanisms of hydrogen peroxide (H2O2) decomposition were examined in a series of soil suspensions at H2O2 concentrations comparable to those found in rainwaters. The formation of hydroxyl radical (OH) as a possible decomposition intermediate was investigated using a new, highly...

pubmed.ncbi.nlm.nih.gov

The OH radical will strip calcium. and form insoluble CaOH.

Here's a pic of 2L of well water that I pHed with KOH. It striped the Ca out immediately and you can see it settle in the bottom.
View attachment 18124616

What does that mean in your own words or in layman's terms?

 

[Three Berries]

What does that mean in your own words or in layman's terms?

Soil with high organic matter will do better due to the lack of the OH- radical. Should not be a problem with soil mixes, would be with high clay or sand mixes I would guess.

When the OH- radical finds some free calcium Ca+ it will strip it out as CaOH, or slaked lime. Which is only slightly soluble in water. I was using KOH as a pH up but when I added it to my well water based nutes, the Ca from the hard water dropped right out.

Calcium Hydroxide

Calcium Hydroxide | Ca(OH)2 or CaH2O2 | CID 6093208 - structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more.

pubchem.ncbi.nlm.nih.gov

 

[blondie]

This is a report for well water I used a few seasons ago for outdoor. Check the PH...

Parameter MCL (mg/L) MRL (mg/L) Result (mg/L)

Aluminum 0.2 0.05 2.51
Antimony 0.006 0.002 nd
Arsenic 0.01 0.002 nd
Barium 2 0.002 0.16
Beryllium 0.004 0.001 nd
Boron 0.05 1.33
Calcium 0.05 4.52
Cadmium 0.005 0.001 nd
Carbon 0.05 nd
Cerium 0.005 nd
Cesium 0.005 nd
Total Chromium 0.1 0.01 nd
Chromium 3+ 0.005 nd
Hexavalent Chromium 0.005 nd
Cobalt 0.02 nd
Copper 1.3 0.01 0.017
Ferric Iron 0.03 0.5
Ferrous Iron 0.03 nd
Iron 0.3 0.03 0.5
Lead 0.01 0.002 nd
Lithium 0.002 nd
Magnesium 0.1 3.55
Manganese 0.05 0.005 0.007
Mercury 0.002 0.0001 nd
Nickel 5 0.01 nd
Phosphorus 0.05 nd
Potassium 0.01 0.88
Selenium 0.05 0.002 nd
Silicon 0.5 nd
Silver 0.1 0.005 nd
Sodium 50 0.1 146.1
Sulfur 0.5 nd
Thorium 0.05 nd
Tin 0.1 nd
Titanium 0.01 nd
Uranium 0.02 nd
Zinc 5 0.01 nd

INORGANICS
Parameter MCL (mg/L) MRL (mg/L) Result (mg/L)
Alkalinity 0.25 232
Ammonia 0.2 nd
Total Carbonate N/A 12
Bromide 0.1 nd
Chloride 250 0.200 29
Color (units in CU) 15 1 184
Conductivity (units in µmhos) N/A 714
Corrosivity, Langelier Saturation Index N/A -0.21
Fluoride 2 0.2 2
Total Hardness (CaCO3) 250 0.25 20
Total Hardness (Grains) N/A 1.17
Nitrate 10 0.3 nd
Nitrite 1 0.2 nd
pH 6.5-8.5 N/A 8.18
Salinity ---- N/A nd
Sulfate 250 0.5 6
Tannins --- 0.5 nd
Total Dissolved Solids (TDS) 500 10 393
Turbidity (units in NTU) --- 0.1 24.3

 

[VerdantGreen]

It is vital to understand the difference between pH and Alkalinity. High alkalinity makes it much harder to adjust the pH. This link is about swimming pools but explains it well.
eg. Rainwater may be low pH but because it has very low alkalinity it is very easy to adjust the pH

The Difference Between pH and Alkalinity | What is pH?

Knowing the difference between pH and alkalinity is vital to your pool’s health, so read on to learn this critical differentiation.

www.thepoolbutler.net

 

[Creeperpark]

This is a report for well water I used a few seasons ago for outdoor. Check the PH...

Parameter MCL (mg/L) MRL (mg/L) Result (mg/L)

Aluminum 0.2 0.05 2.51
Antimony 0.006 0.002 nd
Arsenic 0.01 0.002 nd
Barium 2 0.002 0.16
Beryllium 0.004 0.001 nd
Boron 0.05 1.33
Calcium 0.05 4.52
Cadmium 0.005 0.001 nd
Carbon 0.05 nd
Cerium 0.005 nd
Cesium 0.005 nd
Total Chromium 0.1 0.01 nd
Chromium 3+ 0.005 nd
Hexavalent Chromium 0.005 nd
Cobalt 0.02 nd
Copper 1.3 0.01 0.017
Ferric Iron 0.03 0.5
Ferrous Iron 0.03 nd
Iron 0.3 0.03 0.5
Lead 0.01 0.002 nd
Lithium 0.002 nd
Magnesium 0.1 3.55
Manganese 0.05 0.005 0.007
Mercury 0.002 0.0001 nd
Nickel 5 0.01 nd
Phosphorus 0.05 nd
Potassium 0.01 0.88
Selenium 0.05 0.002 nd
Silicon 0.5 nd
Silver 0.1 0.005 nd
Sodium 50 0.1 146.1
Sulfur 0.5 nd
Thorium 0.05 nd
Tin 0.1 nd
Titanium 0.01 nd
Uranium 0.02 nd
Zinc 5 0.01 nd

INORGANICS
Parameter MCL (mg/L) MRL (mg/L) Result (mg/L)
Alkalinity 0.25 232
Ammonia 0.2 nd
Total Carbonate N/A 12
Bromide 0.1 nd
Chloride 250 0.200 29
Color (units in CU) 15 1 184
Conductivity (units in µmhos) N/A 714
Corrosivity, Langelier Saturation Index N/A -0.21
Fluoride 2 0.2 2
Total Hardness (CaCO3) 250 0.25 20
Total Hardness (Grains) N/A 1.17
Nitrate 10 0.3 nd
Nitrite 1 0.2 nd
pH 6.5-8.5 N/A 8.18
Salinity ---- N/A nd
Sulfate 250 0.5 6
Tannins --- 0.5 nd
Total Dissolved Solids (TDS) 500 10 393
Turbidity (units in NTU) --- 0.1 24.3

That's a lot of stuff in the water. When rain hits the ground it becomes the same as the ground. For super clean water catch it before it hits the ground.

 

[Three Berries]

That's a lot of stuff in the water. When rain hits the ground it becomes the same as the ground. For super clean water catch it before it hits the ground.

Looks like rocky soil?

 

[blondie]

Soil is pretty good but the well is 200+ feet down. It’s awful water. But it’s all that’s available. I only grew there once. If I grow seriously again there, it’s a good idea to catch the rain.

 

[VerdantGreen]

This is an old post of mine from when i used tapwater. the study is interesting.

http://www.usu.edu/cpl/PDF/Optimization_of_SoillessMedia_High_pH_Water_Sources.pdf

High root zone pH reduces nutrient availability and high alkalinity water is strongly buffered around an alkaline pH. Soilless media can be altered to improve nutrient availability. This study was conducted to optimize the composition of soilless media for use with high alkalinity water. Mixes of peat and/or perlite or vermiculite in 50/50 and 33/33/33 volumetric ratios were tested. In some studies, mixes were also amended with up to 2.4 g/L of dolomite limestone to neutralize the initial acidity of the peat. Mixes containing vermiculite settled more, had higher water holding capacity (WHC) and percent plant available water (%PAW), and similar air filled porosity (AFP), compared to mixes containing perlite. Dry mass was measured in corn, peas, tomatoes, and soybeans, and chlorophyll content was measured in corn. The addition of dolomite increased pH and decreased dry mass in corn, soybean, and tomato, but peas were unaffected. Chlorophyll content in corn also declined with increased amounts of dolomite. After a week of daily irrigation, pH 7.8 nutrient solution neutralized the acidity of the peat, without the need for addition of dolomite. Mixes containing vermiculite improved growth and chlorophyll concentration compared to mixes with perlite. The higher cation exchange capacity (CEC) of vermiculite-containing mixes may have improved nutrient availability. A soilless mix of only peat and vermiculite, in approximately equal volumes, resulted in the greatest growth and chlorophyll content when watered with high alkalinity nutrient solution.

obviously the addition of compost, EWC and possibly topsoil would mitigate the effects of watering with alkaline water, but given the pretty fast and dramatic effects shown in the study, i doubt that it would negate the effects completely.

also worth bearing in mind that many organic P sources - such as rock phosphate and bonemeal - are also liming agents in their own right and may exacerbate the problem too.

i use citric acid to reduce the pH of my alkaline tapwater - and my plants seem to do great on it - but recently i wondered if this affect was temporary or permanent - afaik it depends on the type of alkalinity.

lastly, remember that pH and alkalinity are different.

pH is a logarithmic measure (that is, every 1 unit change is a factor of 10) of the concentration of hydrogen ion and that determines the acidity of the solution (acidic if pH < 7). In the opposite direction away from neutrality, at pH > 7, the solution is basic aka alkaline which would be the case for your solution with soda ash. TA is a measure of any chemical species that can accept hydrogen ions so if the TA is high such species combine with the hydrogen that is added from acids such that the effect on pH is far less. Soda ash not only increases pH, but it also increases TA a lot as well. This basically means that though the pH may be measured as high from the Soda Ash, you can't tell how much acid you need to add just from the pH -- you need to know the TA or more easily use the acid demand test as indicated above.

VG

 

[Three Berries]

What to use for pH up? Currently I'm using potassium bicarbonate. And 7.4 well water. After nutes I'm in the mid 6.xs. But soot for high 6s or 7 sometimes. Used ammonia before but the weak stuff.

And how much alkalinity is there is a solution under 7.0? When I mix I can see the CO2 bubbling off from the decomposition of the carbonates. It takes about 6 hours to get a stable reading as it slowly rises. But then I add carbonates to bring it up and that takes 12 hrs to stabilize.