Water PH rising alot overnight

[Buddin Buddy]

I have a problem with my water that I've pretty much had for 2 years now but seems to be getting worse.

So my tap water comes out of the tap about 7.2ph. If I just leave it in a cup and test it the next day it will be 7.8, maybe two or three days later it might be over 8!

When filling my tank I leave it for 24hrs for chlorine to evaporate before adding any neuts. I add neuts and set the PH to near 6. 12hrs later it will be 6.5-6.8. 24hrs later it will be 7.2-7.8.

Yesterday I set the tank to 5.7 and fed plants from the bottom so the water would pool and I could test ph the next morning. I've just tested what's left in the bottom of the trays and its 6.5, after 12hrs.

I just dont understand what is going on, I've bought a 2nd ph meter because I thought it might be that. Both ph meters are calibrated and show a deviation of 0.2 ph between them.

My plants are slowly going yellow (light green atm) looking like lack of nitrogen with stems turning purple as well. I think it's to do with the PH as the plants are only getting the correct PH for less than a day and then the coco PH is above 7 again and I'm getting lockout.

Anybody got any ideas or suggestions as to what is going on? Anything i can add to water to stop ph rising? I can only theorize that the water company is adding some sort of PH stabilizers as this problem only started 2 years ago.

Any advice would be appreciated, thanks.

 

[BoostNBuds]

I would suspect that the water is simply taking that long to gas off. Get an air stone and dont add anything. Check check the ph change over 48hrs maybe checking every 8 hrs until it stabilizes. What ppm are you getting from the tap?

 

[Aqua Man]

Alkalinity and possible source of acid used for ph down. After reading if you have any questions just hit me up.

Marijuana pH Levels for Growing Weed: A Basic Explanation

OK I'm going to do my best to explain PH since its something that is for the most part greatly misunderstood and can be confusing to new growers and even experienced growers alike. This will explain why we need both ppm and PH meters to give us informed information about PH This will be a...

www.thcfarmer.com

 

[Aqua Man]

Just to add PH of tap will usually rise about 0.4. This is due to the carbonic acid content from the break down of organics in a closed pressurized system. Co2 can't escape and if forced into the water to form carbonic acid which will slightly reduce the PH according to the alkalinity of the supply.

You don't need to off gas chlorine. Most tap waters are now using chloramine which is a bond of ammonia and chlorine and even if aerated can last over a week.

The amount in tap water is almost negligible for our purposes but if your really worried about it 1 gram of ascorbic acid (vitamin C)) will neutralize 1ppm of chlorine/chloramine in 100gal of water. So you can calculate that. Water supplies are allowed no more than 4ppm and most are 1-2ppm.

 

[Buddin Buddy]

I would suspect that the water is simply taking that long to gas off. Get an air stone and dont add anything. Check check the ph change over 48hrs maybe checking every 8 hrs until it stabilizes. What ppm are you getting from the tap?

I have an air stone in the tank, I forgot to mention that, and my tap water comes out 0.1 EC (not got a ppm meter).

 

[Aqua Man]

I have an air stone in the tank, I forgot to mention that, and my tap water comes out 0.1 EC (not got a ppm meter).

Airstone is fine. Aeration will help equalize the gasses. If you don't have it co2 can build up for multiple reasons and o2 replenishment is severely reduced.

The ph changing from aeration is due to this gas exchange. Particularly the release of co2. Which when dissolved in what creates carbonic acid.

 

[Buddin Buddy]

Alkalinity and possible source of acid used for ph down. After reading if you have any questions just hit me up.

Marijuana pH Levels for Growing Weed: A Basic Explanation

OK I'm going to do my best to explain PH since its something that is for the most part greatly misunderstood and can be confusing to new growers and even experienced growers alike. This will explain why we need both ppm and PH meters to give us informed information about PH This will be a...

www.thcfarmer.com

Interesting read. So you suggest I add silica and/or ph up to my tank before regular neuts? Ph up sounds counter productive when I'm having ph rise problems, is that right?

My EC meter shows my water is 0.1 EC from tap which I believe is about 50ppm

I'm in coco. If I feed neut mix from the top with a ph 5.8 solution, the runoff at the bottom will often come out around 6.8 and then continue to rise above 7.5 over the next 24hrs, it's pretty annoying to say the least.

Here is a copy and paste from my water companies summary report of water quality in my area:

Typical water hardness:
Mod. Soft
Hardness clarke:
6.93

Summary

Analysis	Typical value	Law Limit	Units
Hardness Level	Mod. Soft
Hardness Clarke	6.93		Clarke
Aluminium	<16.0	200	µg Al/l
Calcium	32.2		mg Ca/l
Residual chlorine - Total	0.58		mg/l
Residual chlorine - Free	0.48		mg/l
Coliform bacteria	0	0	number/100ml
Colour	<1.67	20	mg/l Pt/Co scale
Conductivity	269	2500	uS/cm at 20oC
Copper	<0.0095	2	mg Cu/l
E.coli	0	0	number/100ml
Iron	<13.8	200	µg Fe/l
Lead	<0.861	10	µg Pb/l
Magnesium	4.69		mg Mg/l
Manganese	<0.469	50	µg Mn/l
Nitrate	<7.32	50	mg NO3/l
Sodium	17.7	200	mg Na/l

This is the full report

Parameter	Min	Average	Max	Units	Law Limit	Samples	%Failed
2,4-D	<0.0100	<0.0126	0.0210	µg/l	0.1	23	0
2,4-DB	<0.0210	<0.0217	<0.0220	µg/l	0.1	10	0
Alkalinity as CaCO3	27.5	39.1	54.9	mg/l		7	0
Aluminium	4.05	<16.0	<33.7	µg Al/l	200	25	0
Ammonium (ammonia and ammonium ions)	<0.0154	<0.0248	<0.0540	mg NH4/l	0.5	11	0
Antimony	<0.440	<0.440	<0.440	µg Sb/l	5	8	0
Arsenic	0.140	<0.197	<0.480	µg As/l	10	9	0
Benzene	<0.157	<0.157	<0.157	µg/l	1	23	0
Benzo(a)pyrene	<0.0019	<0.0020	<0.0020	µg/l	0.01	11	0
Boron	0.0096	<0.0151	0.0226	mg B/l	1	24	0
Bromate	<0.120	<0.292	0.540	µg BrO3/l	10	10	0
Cadmium	<0.100	<0.100	<0.100	µg Cd/l	5	9	0
Calcium	20.8	32.2	44.9	mg Ca/l		24	0
Carbetamide	<0.0100	<0.0100	<0.0100	µg/l	0.1	24	0
Chloride	14.0	24.7	35.0	mg Cl/l	250	24	0
Chromium	<0.160	<0.332	1.86	µg Cr/l	50	10	0
Residual chlorine - Total	0.28	0.58	1.01	mg/l		52	0
Residual chlorine - Free	0.18	0.48	0.95	mg/l		52	0
Chlortoluron	<0.0070	<0.0070	<0.0070	µg/l	0.1	24	0
Colony counts after 3 days at 22 deg C	0	3	75	number/1ml		26	0
Coliform bacteria	0	0	0	number/100ml	0	52	0
Colour	<1.21	<1.67	<2.16	mg/l Pt/Co scale	20	24	0
Conductivity	96.4	269	389	uS/cm at 20oC	2500	24	0
Copper	<0.0032	<0.0095	0.0289	mg Cu/l	2	9	0
Clostridium perfringens (including spores)	0	0	0	number/100ml	0	10	0
Clopyralid	<0.0080	<0.0112	<0.0120	µg/l	0.1	23	0
Cyanide	<2.33	<3.26	<3.91	µg CN/l	50	24	0
1,2-dichloroethane	<0.459	<0.459	<0.459	µg/l	3	23	0
Diazinon	<0.0080	<0.0080	<0.0080	µg/l	0.1	24	0
Diuron	<0.0080	<0.0080	<0.0080	µg/l	0.1	24	0
E.coli	0	0	0	number/100ml	0	52	0
Enterococci	0	0	0	number/100ml	0	10	0
Fluoride	0.0200	0.0275	0.0500	mg F/l	1.5	48	0
Fluroxypyr	<0.0080	<0.0141	<0.0160	µg/l	0.1	23	0
Glyphosate	<0.0079	<0.0097	0.0516	µg/l	0.1	24	0
Hardness Total as CaCO3	63	99	143	mg CaCO3/l		24	0
Iron	<2.10	<13.8	52.7	µg Fe/l	200	24	0
Isoproturon	<0.0080	<0.0080	<0.0080	µg/l	0.1	24	0
Lead	<0.550	<0.861	<0.950	µg Pb/l	10	9	0
Linuron	<0.0100	<0.0100	<0.0100	µg/l	0.1	24	0
Magnesium	2.58	4.69	7.89	mg Mg/l		24	0
Manganese	<0.370	<0.469	0.790	µg Mn/l	50	24	0
MCPA	<0.0110	<0.0131	<0.0160	µg/l	0.1	23	0
Mecoprop	<0.0100	<0.0127	<0.0190	µg/l	0.1	23	0
Mercury	<0.0400	<0.0446	<0.0500	µg Hg/l	1	24	0
Metazachlor	<0.0080	<0.0080	<0.0080	µg/l	0.1	23	0
Metaldehyde	<0.0045	<0.0048	<0.0050	µg/l	0.1	23	0
Nickel	<0.770	<1.14	2.19	µg Ni/l	20	8	0
Nitrite	<0.0062	<0.0095	<0.0115	mg NO2/l	0.5	10	0
Nitrate	<1.77	<7.32	12.4	mg NO3/l	50	10	0
(Nitrate)/50 plus (nitrite)/3	0.0330	0.146	0.246	mg/l	1	10	0
Odour (quantitative)	0	0	0	dilution number at 25oC	0	25	0
Total organic carbon	1.14	1.73	2.53	mg C/l		24	0
Polycyclic aromatic hydrocarbons (sum of 4 PAHs)	0.0000	0.0000	0.0000	µg/l	0.1	11	0
Pesticides - Total	0.0000	0.0015	0.0516	µg/l	0.5	71	0
Hydrogen ion (pH)	7.03	7.35	7.73	pH value	9.5	46	0
Propyzamide	<0.0100	<0.0100	<0.0100	µg/l	0.1	14	0
Selenium	<0.200	<0.279	<0.990	µg Se/l	10	10	0
Sodium	13.7	17.7	21.8	mg Na/l	200	8	0
Sulphate	41.6	49.1	77.6	mg SO4/l	250	24	0
Taste (quantitative)	0	0	0	dilution number at 25oC	0	24	0
Tetrachloromethane	<0.0600	<0.0710	<0.108	µg/l	3	8	0
Trihalomethanes - Total	19.8	30.4	50.1	µg/l	100	8	0
Triclopyr	<0.0080	<0.0189	<0.0250	µg/l	0.1	23	0
Tetrachloroethene and trichloroethene	0.0000	0.0000	0.0000	µg/l	10	8	0
Turbidity	<0.16	<0.20	<0.24	NTU	4	24	0

It says my average Alkalinity is 39.1, how can I use this information to help me with PH issues?

Alkalinity and possible source of acid used for ph down. After reading if you have any questions just hit me up.

Marijuana pH Levels for Growing Weed: A Basic Explanation

OK I'm going to do my best to explain PH since its something that is for the most part greatly misunderstood and can be confusing to new growers and even experienced growers alike. This will explain why we need both ppm and PH meters to give us informed information about PH This will be a...

www.thcfarmer.com

 

[Aqua Man]

At 0.1 EC I'd say it's more than likely your alkalinity is to low. Thats 50ppm

 

[Aqua Man]

Yes by looking at that water report that's exactly your problem. You also have no need to worry about chlorine... very small amounts.

Yes either potassium bicarbonate or potassium silicate will work.

The reason be is like this... let's call alkaline source base represented by B. And wel will call acid sources A.

your tap has low amount of B

so it will look like this.

B

now you ph down adding acid and it looks like this.

B/A ratio 50/50 acid to base say ph 6

Now when you add more base first it looks like this.

BBBBBBBBBB.

so to bring the PH down you now need to add more acid to make it equal so you get this.

BBBBBBBBBB/AAAAAAAAAA same thing here 50/50 ratio ph of 6

many things influence your ph so let's look at your tap first.

B/A now add or reduce any acid or base. Eg when plant uptakes nitrate the ion exchange will cause ph to rise so add a B to you mix.

BB/A now the ratio is 66.6/33.3 you ow have twice as much base as acid causing ph to shift from 6 to 7.

Now in the buffered solution the same scenario.

BBBBBBBBBBB/AAAAAAAAAA ratio is now 52.5/47.5 ph only changes from 6 to 6.1 almost no change to ph.

That make it a bit easier to understand?


What source of ph down are you using?

 

[Buddin Buddy]

Yes by looking at that water report that's exactly your problem. You also have no need to worry about chlorine... very small amounts.

Yes either potassium bicarbonate or potassium silicate will work.

The reason be is like this... let's call alkaline source base represented by B. And wel will call acid sources A.

your tap has low amount of B

so it will look like this.

B

now you ph down adding acid and it looks like this.

B/A ratio 50/50 acid to base say ph 6

Now when you add more base first it looks like this.

BBBBBBBBBB.

so to bring the PH down you now need to add more acid to make it equal so you get this.

BBBBBBBBBB/AAAAAAAAAA same thing here 50/50 ratio ph of 6

many things influence your ph so let's look at your tap first.

B/A now add or reduce any acid or base. Eg when plant uptakes nitrate the ion exchange will cause ph to rise so add a B to you mix.

BB/A now the ratio is 66.6/33.3 you ow have twice as much base as acid causing ph to shift from 6 to 7.

Now in the buffered solution the same scenario.

BBBBBBBBBBB/AAAAAAAAAA ratio is now 52.5/47.5 ph only changes from 6 to 6.1 almost no change to ph.

That make it a bit easier to understand?


What source of ph down are you using?

I have a PH down and up by the same manufacturer
PH Down says its "Phosphoric Acid 81%"
PH Up says its "Potassium Hydroxide 25%"

I have another PH down product by a different manufacturer/brand which is exactly the same as above

And I have another PH down and up which is by an entirely different manufacturer/brand and this one sells itself as being "Organic"
PH Down says its "Citric Acid"
PH Up says its "Humic Acids 4.91%"
I dont like using these organic PH down and Up products because it takes ALOT to move the PH in either direction.

The Silica product I have does not tell me what its derived from, only that its "Highly Soluble Silica" and that I should add at a level same as base neuts. So if 2mil per ltr of A and B products I should add 2mil per ltr of Silica.

Its strange that I've always been told not to add PH up and down to the same solution. Now your telling me i should preload my water with PH Up which will likely take my PH over 8, and then reduce it after neuts have been added with PH down? Is this right? Do I use PH Up or Silica or both before adding neuts?

 

[Aqua Man]

I have a PH down and up by the same manufacturer
PH Down says its "Phosphoric Acid 81%"
PH Up says its "Potassium Hydroxide 25%"

I have another PH down product by a different manufacturer/brand which is exactly the same as above

And I have another PH down and up which is by an entirely different manufacturer/brand and this one sells itself as being "Organic"
PH Down says its "Citric Acid"
PH Up says its "Humic Acids 4.91%"
I dont like using these organic PH down and Up products because it takes ALOT to move the PH in either direction.

The Silica product I have does not tell me what its derived from, only that its "Highly Soluble Silica" and that I should add at a level same as base neuts. So if 2mil per ltr of A and B products I should add 2mil per ltr of Silica.

Its strange that I've always been told not to add PH up and down to the same solution. Now your telling me i should preload my water with PH Up which will likely take my PH over 8, and then reduce it after neuts have been added with PH down? Is this right? Do I use PH Up or Silica or both before adding neuts?

Ok let me explain... normally you don't add both because you can change your nutrient ratios. But you need to have a PH buffer or the PH will be very unstable.

So first start low. Take your tap water and add 1/2 tsp per 5 gal of ph up. Measure ph and if over 8 the reduce to 6.5 with ph down before adding your nutrients. This is to make sure you don't have nutrients precipitate out of the solution.

Then add your nutrients as directed. I suggest half the recommended does of each but I won't get into that as this about ph and need to get that fixed.

After adding nutrients ph down to 5.8.

Check the mix in an hr or 2 after mixing if using water straight from the tap as the PH may rise slightly. If it's up ph down to 5.8.

From there test it again in 24 hrs. The PH should rise about 0.2-0.3. If it's more then we will adjust the buffer at that point based on the change you see.

Once we figure out the amount need for a proper buffer your golden and will know exactly how much to add for a nice stable ph.

 

[Aqua Man]

Also never use citric acid it will react with the bicarbonate creating co2 and off gas. Causing your ph to rise after a very short period of time.

Stick to phosphoric acid.

 

[Aqua Man]

Can you also post a pic of the plants?

 

[Buddin Buddy]

Also never use citric acid it will react with the bicarbonate creating co2 and off gas. Causing your ph to rise after a very short period of time.

Stick to phosphoric acid.

Thanks man, this is a great help, I'll give it a go when I get home from work later and let you know how I got on.

 

[BoostNBuds]

Ok let me explain... normally you don't add both because you can change your nutrient ratios. But you need to have a PH buffer or the PH will be very unstable.

So first start low. Take your tap water and add 1/2 tsp per 5 gal of ph up. Measure ph and if over 8 the reduce to 6.5 with ph down before adding your nutrients. This is to make sure you don't have nutrients precipitate out of the solution.

Then add your nutrients as directed. I suggest half the recommended does of each but I won't get into that as this about ph and need to get that fixed.

After adding nutrients ph down to 5.8.

Check the mix in an hr or 2 after mixing if using water straight from the tap as the PH may rise slightly. If it's up ph down to 5.8.

From there test it again in 24 hrs. The PH should rise about 0.2-0.3. If it's more then we will adjust the buffer at that point based on the change you see.

Once we figure out the amount need for a proper buffer your golden and will know exactly how much to add for a nice stable ph.

Is the idea of adding ph up at the start and then moving down just to give you a more consistent starting point?

 

[Aqua Man]

Is the idea of adding ph up at the start and then moving down just to give you a more consistent starting point?

To to provide a bigger buffer. By adding more alkalinity and acid it creates a more stable ph.

See the link I posted and further explanation on post #9

 

[BoostNBuds]

I did, thanks for the link. I was just making sure I was on the right "thought path" lol. Thanks again.

 

[Og_punkgenetics]

I have a problem with my water that I've pretty much had for 2 years now but seems to be getting worse.

So my tap water comes out of the tap about 7.2ph. If I just leave it in a cup and test it the next day it will be 7.8, maybe two or three days later it might be over 8!

When filling my tank I leave it for 24hrs for chlorine to evaporate before adding any neuts. I add neuts and set the PH to near 6. 12hrs later it will be 6.5-6.8. 24hrs later it will be 7.2-7.8.

Yesterday I set the tank to 5.7 and fed plants from the bottom so the water would pool and I could test ph the next morning. I've just tested what's left in the bottom of the trays and its 6.5, after 12hrs.

I just dont understand what is going on, I've bought a 2nd ph meter because I thought it might be that. Both ph meters are calibrated and show a deviation of 0.2 ph between them.

My plants are slowly going yellow (light green atm) looking like lack of nitrogen with stems turning purple as well. I think it's to do with the PH as the plants are only getting the correct PH for less than a day and then the coco PH is above 7 again and I'm getting lockout.

Anybody got any ideas or suggestions as to what is going on? Anything i can add to water to stop ph rising? I can only theorize that the water company is adding some sort of PH stabilizers as this problem only started 2 years ago.

Any advice would be appreciated, thanks.

Do you know what the PPM of the water is coming out of the tap? Is it a municipal water source? I have found in the past that when the water table drops, the PPM's get higher and alkaline , but I'm on a community well system. Also it's a good idea to oxygenate your water. 64°F is the temperature that oxygen is most in solution. I constantly have water movement in my fill tank. Temperature is also important

 

[Buddin Buddy]

Can you also post a pic of the plants?

Ok from start.

I'm growing 9x Barneys Farm Tropicana Banana from clones, 2nd time growing this strain, first time i did 3x from seed, got 37 oz from 3 plants, from approx. 10 week flower, gave them 5 week growth stage though because of problems. These plants stretch like crazy once flipped to flower so I had to bend them in all kinds of directions into netting as they would 100% hit top of tent (2m high). I think i made a post on this website when I was having problems with the last one in growth stage, likely my problem was PH. Plants were slowly going yellow, with purple stems, just like this time. Anyway when I moved into flowering the problems went away for some reason and I got a good yield so I'm doing them again, this time 9 tho.

I'm using the same light, a OCL 660w LED (1.1mtr x 1.1mtr light, currently on the lowest setting 400w) in a 1.5m x 1.5m tent

I'm using the same system EasyFeed (bottom feeding system) and the same medium as last time 60/40 coco pebbles mix, tho last time I added perlite to the mix, this time i havent added any perlite. I'm using BCuzz coco as my A&B feed, same as last time.

Currently just started week 2 growth, tho they were in small pots for about a week prior to transplanting to 22ltr fabric pots. Oh and last time i used 30ltr fabric pots.

One of the plants (the largest one in top right corner) is from a aeroponics incubator (1 survived out of 20 likely PH issues again) so its the largest because it had the most roots. The other 8 cuttings are from a normal rockwell cube incubator system. So out of like 60 clones i took only about 20 survived, i think it was the same PH issue wrecking my clones, most didnt even root at all.

As you can see the largest one is slowly going yellow with purple stems which makes me think its a lack of nitrogen, i.e out of PH range for uptake.

Here a few closeups of a few of the other plants

They are getting pretty tall now, i havent toped them yet which im planning to do very soon.

And here is a picture of my mother plant which is actually in soil but I'm pretty sure im under feeding it as its getting pretty much the same level of feed as the main plants atm (0.5ml per ltr A+B), tho also probably having PH issues, looks like lack of nitrogen again.

 

[Buddin Buddy]

Ok let me explain... normally you don't add both because you can change your nutrient ratios. But you need to have a PH buffer or the PH will be very unstable.

So first start low. Take your tap water and add 1/2 tsp per 5 gal of ph up. Measure ph and if over 8 the reduce to 6.5 with ph down before adding your nutrients. This is to make sure you don't have nutrients precipitate out of the solution.

Then add your nutrients as directed. I suggest half the recommended does of each but I won't get into that as this about ph and need to get that fixed.

After adding nutrients ph down to 5.8.

Check the mix in an hr or 2 after mixing if using water straight from the tap as the PH may rise slightly. If it's up ph down to 5.8.

From there test it again in 24 hrs. The PH should rise about 0.2-0.3. If it's more then we will adjust the buffer at that point based on the change you see.

Once we figure out the amount need for a proper buffer your golden and will know exactly how much to add for a nice stable ph.

Ok so I have a 100 ltr water tank.
Filled it yesterday PH was 7.5
Added airstone, left for 24hrs
Tested PH today 8.1
Added 15mil PH Up (1/2 tsp to 5gal)
Ph after adding PH Up 9.8!
Added 10mil PH down for PH 6.5
Haven't added neuts yet as plants dont need feeding for at least another day or two (still water in trays).
Will test PH of water again in a few hours and see how much its changed from 6.5 and report back.