CO2 and Ph

[kiko]

you should be so lucky your ph goes down instead of up...most people have to add peat moss..driftwood..almond leaves and at the end of the day...very small changes
you can literally control the ph with your air pump...increase it to increase ph and lower it to lower ph...no need for co2 as your ph tends to go down....
now everybody else...like ME where ph goes up...
let's see...carbon filter....about 15 bio balls...(they just look cool going up and down inside the sump)...driftwood...almond leaves
and to me VERY useful..not everyone likes to fork the $$ for it but.....a PH controller...everytime ph goes up to 7.2 it turns on my co2 and lowers it to 6.95
then comes the issue with co2 itself...you can either make it yourself with dry ice or some other methods you can find on youtube or something or simply have multiple tanks/bottles and just keep them in reserve...
something I've never tested but read about it a while back was using a venturi pipe with an air connection vent to act as an oxygen remover or a vacuum degassing pump.
as you add co2 into the water there's more co2 than oxygen...and with a ph controller for eg..you're aiming for that balance at around a neutral 7 where co2 is the same as oxygen
but you're wasting money on co2 etc....
now...imagine you have 100k parts co2 and 120k oxygen and your ph is around 8ish the oxygen remover would literally bring down the oxygen in this case to 100k and balance would be restored again.
in your case where your ph is going down you don't need nothing fancy...just a small control valve on a sponge filter and a splitter to a diffuser (a diffuser will get better aeration than an air stone as the bubbles are smaller)
open the control valve to max....wait for your ph to be around .2 less than what you want then slowly decrease it until you stabilize it
BUT at the end of the day you said your setup is fairly new...2 months old...with tap at 7.2-7.4
If I was you I'd be looking is for the reason for that big drop because 7.2 to 4 is a bit much..whether it's too many plants...or not enough light or something's rotting in your tank or maybe you're over overfeeding?!?
because usually ph tends to go up...and then overtime with crap in the tank even with water changes and gravel vac will eventually start dropping..
but not in a 2 month old

Good luck

 

[TwoTankAmin]

Water chemistry is not simple nor easy. And the more things we add to our water, the more complicated things get. I ran pressurized co2 in one high tech planted tank for about a decade. So I know how things can go wrong. Every tank is unique because of the combination of factors involved. Just the volume and type of plants used can change the chemistry, The carbonates that help keep one's pH stable are also used by the nitrifying bacteria and even by some plants.

Next, acid water tends to damage water pipes, so it is not uncommon for a water companies to raise the pH. They may also do this for other reasons. So trying to fight the water companies chemistry can be a problem. Some folks are reduced to using RO or even RO?DI water and then remineralizing it to insure it has the proper parameters is the only solution.

I have always been space constrained, so when I ran my CO2 added tank I had no pH controller and I ran a somewhat lean mix 24/7- 1 bpm. It worked for me because I eventually decided to give up the tank because of the amount of time I had to spend pruning and replanting. I keep fish first and foremost and I use plants in those tanks where they are of benefit to the fish. I also breed plecos in tanks with no plants and some without any substrate. These tanks use massive amounts of media and hold some of the clearest water in any of my tanks.

Every time we mess with the water chemistry in any given tank, the result will rarely be to change just one parameter. You cannot affect KH without having it effect pH. it may also effect the bacteria and even the plants in a tank. You can increase hardness without having an effect on some other parameters.

I cannot treat all of my planted tanks the same. I have a 75 gal. tank loaded with plants, enough for two tanks of this size. And then there are a ton of Amano shrimp and even more assassin snails. I noticed the pants were not doing as well as would have expected. I have basically neutral pH and soft water. What was happening was the bacteria, the plants and the inverts all needed some of the same things. I keep mostly soft water fish and have always been leery of raising the GH/KH/pH. But it turned out that the solution to my problem was:

SeaChem Equilibrium.
Guaranteed Analysis
Amounts per 1 g

Soluble Potash (K2O) 23.0%
Calcium (Ca) 8.06%
Magnesium (Mg) 2.41%
Iron (Fe) 0.11%
Manganese (Mn) 0.06%

Derived from: potassium sulfate, calcium sulfate, magnesium sulfate, ferric sulfate, manganese sulfate.

I have a tendency to intuit things rather than rely on the directions. So I stared by adding a small amount to the fertilizers when I added them after a water change. I have used Tropica fertilizers for my plants for over 20 years now. So I added a small amount of Equilibrium when I got it and I noticed the plants improved some. Over time I increased the the amount I was using and also started to use it in a couple of other heavily planted tanks with shrimp and snails. The result is my plants are very happy and doing great. The one thing i can say with 100% certainty is that the amount of Equilibrium I am adding is a less than what is suggested by SeaChem. Here is a pic of the tank. It has even more plants in it today than in the pic which was taken a year ago. There is less open space.

I was afraid adding Equilibdrium would change my GH etc. but in the amounts i was adding it it worked more as a fert. than a water hardener:

Equilibrium™ is specifically designed to establish the ideal mineral content for the planted aquarium. Equilibrium™ contains no sodium or chloride (which can be detrimental to a planted aquarium at elevated levels). Equilibrium™ is ideally suited for use with RO (reverse osmosis) or DI (deionized) water or any mineral deficient water. Equilibrium™ raises the essential mineral/electrolyte content (General Hardness) of the water to balance with and promote stability of the carbonate hardness.

The fish in the above tank are corys- paleatus and albino aeneus, rummy nose and purple emperor tetras, orange fin danios and a lot of amanos and assassin snails. Plants are assorted anubias, crypts, java fern and long leaf Hygros.

 

[Alice B]

I used to have very crowded tanks, back in the 90s, and if just CO2 from fish, flake and waste was dropping pH too fast (my water there was quite low in KH, btw) I would put an air stone in the tank and it seemed to release the CO2 from the water, possibly by breaking surface tension, and slow the Ph drop

 

[Alice B]

I thought I had my ph pretty stable between 5.8 and 6.0 for about 4 days, but today I cleaned my fluval filter and all of a sudden my ph is balooning up. From like 6.0 to 6.9 in the course of an hour. I replaced the charcoal, phosphate and ammonia filters. Is there something that could be causing ph to go up that I am missing?

remove phosphate and pH might go up

 

[dR3ws3r]

Well it has been a while since I posted. After making some adjustments, I have my tank in what I believe is a good state. I have upped my water changes to 20-25% every 3 days, and in general my PH has settled in the low 7's. My tap water for the longest time has come out on the softer side with a PH in the high 6's. Today I went to do a water change and looked at the PH of my tap and I was surprised to see the PH of the water in the bucket was 8.4. A pretty radical change. My water authority had already told me that my area will see water from different sources depending on the time of year, but I didn't think any source near me was this high.

I know that TDS isn't always a meaningful measurement, but oddly the TDS of my water this morning was around the same as it has been for the last few months, around 50-60. Additionally a quick test strip (fwiw) had my general hardness and KH the same as usual. GH of 4 and KH of 1 (degrees).

Is there something that water authorities will add to water to raise the PH but that doesn't raise dissolved solids? I didn't really give it too much thought, but I kind of felt that the two went hand in hand to a degree. Certainly adding carbonates will raise both (I believe), but are there other things (organics perhaps), that raise PH but not the amount of dissolved solids in the water?

Also I use an APEX PH probe for measuring PH and I just recently calibrated it. So I don't think it is instrument error.

 

[Byron]

Organic matter dissolved will lower pH (unless buffered by the GH/KH), never (so far as I know) raise it. The blackwater in the Amazon basin for example is high in organics but the GH is zero and the TDS is near zero.

 

[Alice B]

there are things they add to raise pH but not raise KH, because Arlington, TX buffers pH to 7.6 in winter when their water comes from Cedar Creek Reservoir, but when I did water changes my tank pH would drop due to the low KH. I no longer live there, now high pH is my problem

 

[TwoTankAmin]

TDS are basically conductivity times a specific constant. My digital monitor offers two different multipliers. What makes TDS (or conductivity) important is because of what it measures:

Total dissolved solids (TDS) are the amount of organic and inorganic materials, such as metals, minerals, salts, and ions, dissolved in a particular volume of water; TDS are essentially a measure of anything dissolved in water that is not an H2O molecule.

We all know what some of the possible ions in our water are from the cycle: Nitrite (NO2−), Nitrate (NO3-) and Ammonium (NH⁺ ₄). The minus and plus signs indicate whether the ino has a positive or negative charge (Basically, it has missing electrons or extra electrons which have negative charge).

TDS counts anything dissolved in the water. What is does not do is tell us from what things there only the total of all things. So it is possible to have the exact same TDS reading in two different tanks but have almost nothing in common dissolved in the water. However, the fish and other aquatic critters we may keep which usually know the difference. If we know out tap parameters and we know the sort of things that are contributing to TDS in a tank, it often makes it possible to intuit the cause of an unexpected change in TDS.

This requires we are familiar with our water parameters, what additives we might be using and what specific essntail things do we know re important for out specific tank to be healthy.

 

[dR3ws3r]

Well, I attached some apex plots to this post. Yesterday shortly after putting tap water in the bucket, I put the ph probe in and the ph was 8.44. I put the probe back in my 10 gallon quarantine tank and went about my day. At night before I went to sleep I put the probe back in the bucket for a sanity check and it was 7.77. I left it in there till this morning and it is down to 7.42.

Does this mean that whatever is causing a spike in my ph in my tap water is off-gassing? Is this possibly a ph/temperature correlation? It has dropped a single point of ph in 24 hours.

I put an active airstone in the bucket this morning to see if I could get whatever gasses that are in the the water to exit a little swifter, as the ph still appears to be dropping.

 

[dR3ws3r]

It has been over a month since I set up my quarantine tank. It is a 10 gallon with aquasoil a few dragon stones and some simple, easy to grow plants. The PH continues to be in the 5.7-5.8 range, despite a daily 50% water change with water that is in the 7.0-7.3 range. I think that because I have low KH water , that the acid being leached from the soil is having a pronounced affect on the tank water PH, but how long would your realistically expect it to take to dilute the acid forming products in the aquasoil to a point where the tank water PH gets much closer to the tap water PH of around 7? Since there are no fish in the tank, would is just be easier to strip it down and run water over the soil for a while, or some equivalent action.

Someone will probably ask why I used aquasoil in the first place ... and to that I would say that I wanted to mimic the conditions in the main tank, and I wanted plant growth in the quarantine tank so the fish would have places to hide, and have hopefully a healthier ecosystem. And ignorance on my part, not realizing how profound the PH effect would be on the tank water.

 

[Byron]

You do not need soil of any type for good plant growth; inert sand with sufficient nutrient supplement (substrate tabs, with or without liquid fert) is just as good. And it avoids the soil issues.

The organics in the soil will create ammonia and CO2, and this will continue until the organics are gone. Most soil sources suggest this is up to a year.

Lowering pH is due to the CO2 and I suspect the GH and KH are low so there is no buffering to counter this. This is not at all dangerous provided you keep soft water fish.

 

[dR3ws3r]

Yesterday I did a filter change and 25% water change on my 10 gallon quarantine tank. I was alarmed when I saw that my PH had risen from the low 7's to 8. I checked the PH on my tap water that had been sitting in a bucket for 2 days and it was 8.04. Checking the TDS was 55. It is still on the soft side, but my water authority has done something to the water to raise the PH. I turned on the airpump/airstone and over the course of a few hours the water PH dropped to 7.35. I feel like this is the trials and tribulations of basically having a sub 1 KH water supply. Even the simplest thing like pumping air from the room into the tank can have a dramatic affect on the PH (I'm assuming by adding CO2 from the room more directly or just more surface agitation). Although I think it is more of the former, as if I measure what is in a bucket, it is high, bubbling the water lowers it, and if I turn off the bubbler, the PH rises again (over the course of hours). I appreciate the soft water, but the PH changes really concern me.

 

[Byron]

Yesterday I did a filter change and 25% water change on my 10 gallon quarantine tank. I was alarmed when I saw that my PH had risen from the low 7's to 8. I checked the PH on my tap water that had been sitting in a bucket for 2 days and it was 8.04. Checking the TDS was 55. It is still on the soft side, but my water authority has done something to the water to raise the PH. I turned on the airpump/airstone and over the course of a few hours the water PH dropped to 7.35. I feel like this is the trials and tribulations of basically having a sub 1 KH water supply. Even the simplest thing like pumping air from the room into the tank can have a dramatic affect on the PH (I'm assuming by adding CO2 from the room more directly or just more surface agitation). Although I think it is more of the former, as if I measure what is in a bucket, it is high, bubbling the water lowers it, and if I turn off the bubbler, the PH rises again (over the course of hours). I appreciate the soft water, but the PH changes really concern me.

The pH change is more likely natural, though the water authority might be adding something. You should check with them, if they are adding "x" it is public information.

There is a normal pH shift due to dissolved CO2. Water running through the pipes to your home can assimilate a lot of dissolved CO2. This will naturally dissipate out in 24 hours. Depending upon the level of CO2, the pH can shift accordingly. The pH in the aquarium, or after out-gassing the CO2 (24 hours), will be the actual pH of the water. Except if they add something to increase the pH. I had to manage this ever since 2001.

A pH fluctuation every 24 hours is natural in most habitat waters. It depends upon the atmospheric CO2, the presence of aquatic plants, and the natural GH and KH of the water. You also see this in planted tanks; mine varied every 24 hours from about 6.0 up to 6.4 or some were 6.6 during darkness, then lowering during the day. This is not a problem for fish.

 

[Alice B]

Also plants give off co2 at night I thought. I know on my reef tank pH was higher in daytime, lower at night and there was no change in my pumps or aeration and I sure didn't deliberately add CO2

 

[Byron]

Also plants give off co2 at night I thought. I know on my reef tank pH was higher in daytime, lower at night and there was no change in my pumps or aeration and I sure didn't deliberately add CO2

Yes, but they do this 24/7. All fish and plants consume oxygen and release CO2 continually, day and night, at (so far as I know) a fairly stable rate; some bacteria do as well. It is the photosynthesis that changes this; during sufficient daylight (intensity) aquatic plants use the CO2 in the water and release oxygen as a waste product. Then during darkness the CO2 rebuilds because the plants are no longer using it. This is where the CO2 from organic matter being broken down in the substrate enters the picture; during the day it primarily gets used up by plants, but it builds up during darkness.