(reverse Osmosis)

[Lorna]

As you probally know I have a prob with my PH it keeps rising no matter what I do to it. I have tested everything in the tank (no probs there) even the tap water PH is lower then my tank. It is also happening to my other tank too. I found a link on this forum that was explaining about lowering PH. A few questions:

Why does bogwood have a limited effect?
How do you inject CO2 into the tank? and why does that work?
and what the heck is RO? Reverse Osmosis?

Ok understand RO more now, does anyone have one of these units?

 

[loachman]

1. bogwood is limited mainly because it works by releasing tannins (acids) from the wood into the water. There is a limted supply of acid in it.

2. CO2 + H2O (water) <=> H2CO3 (carbonic acid) which lowers pH

Depending on the hardness of your water this may have a weaker or stronger effect on the pH.

You can get it into the water by using a DIY CO2 system which is basically a 2 liter bottle filled with yeast and sugar water, then hosed into the tank. You typically put a diffusor on the end of the hose to give more efficient dissolving of the gas into the water.

3. Osmosis is the moving of water from a area of low salt concentration to one of high salt concentration, typically through a membrane. Reverse osmosis is the moving of water from high salt concentration to low salt concentration under pressure. (you force "salty" water through a membrane that doesn't allow salt through, yielding purer water).

 

[sinistral]

Have you tried putting some tap water in a glass and letting it sit overnight, then testing it the next day?

Sometimes water and sewage companies will drive a pH downwards with CO2 or something else to achieve a neutral pH.

This means that the pH of your local water supply actually is 8.0, but the water company using CO2 makes it come out of the tap at 7.0.

CO2 is a gas which can remain dissolved in tapwater for a certain period of time. Since it's a gas, it will diffuse gradually out of the water over time. CO2 is acidic, so when it is dissolved in water, it will cause the pH of water to decrease.

If you let the water sit, or aerate it, for 24 hours, the CO2 will diffuse out of your water, the pH will rise, and you should get a more accurate reading.

If this occurs, the most likely cause of your elevated pH is that the water itself has a natural pH of 8.0, that CO2 buffering in your tapwater by the company is causing it to come out of the tap temporarily at 7.0, and that there is not a problem within your tank causing the pH rise.

Another way of testing this is to have your local aquarium store check or calculate the carbonate hardness of local tapwater.

As most people advised in the other thread, fighting against pH is a losing battle. You will likely never get it to set at exactly where you'd like it to be.

 

[Lorna]

Have you tried putting some tap water in a glass and letting it sit overnight, then testing it the next day?

Sometimes water and sewage companies will drive a pH downwards with CO2 or something else to achieve a neutral pH.

This means that the pH of your local water supply actually is 8.0, but the water company using CO2 makes it come out of the tap at 7.0.

CO2 is a gas which can remain dissolved in tapwater for a certain period of time. Since it's a gas, it will diffuse gradually out of the water over time. CO2 is acidic, so when it is dissolved in water, it will cause the pH of water to decrease.

If you let the water sit, or aerate it, for 24 hours, the CO2 will diffuse out of your water, the pH will rise, and you should get a more accurate reading.

If this occurs, the most likely cause of your elevated pH is that the water itself has a natural pH of 8.0, that CO2 buffering in your tapwater by the company is causing it to come out of the tap temporarily at 7.0, and that there is not a problem within your tank causing the pH rise.

Another way of testing this is to have your local aquarium store check or calculate the carbonate hardness of local tapwater.

As most people advised in the other thread, fighting against pH is a losing battle. You will likely never get it to set at exactly where you'd like it to be.

THANKYOU!!! I am so pleased that you posted this info for me. Its all beginning to make a bit more sense. I will leave some tap water overnight to see what happens. The prob is that my fish have gotten quite distressed at the PH being so high. It measured at 8.6 at one time and nearly killed them. The only way that I am controlling it now is by H20 changes everyday. I have got clown loaches, tetras and platys. The loaches seem to be the worst affected by this.

thnx again every1

 

[sinistral]

I'll be interested to hear how it turns out. Please keep us posted.

 

[Lorna]

Hi. I let the tap water stand over night and I tested the PH and it measured at 8.2!! So that is the problem, what can I do about this?

 

[Jimb0b]

Here's an beginner faq about water chemistry. http/faq.thekrib.com/begin-chem.html

 

[Lorna]

thanks for that jimbob. Now I understand it. If I used mineral water and avoided using tap when doing water changes would that slowly change the KH amount over time, if the alkalinity in the mineral water is low?

 

[sinistral]

Lorna, I would avoid trying to do pH changes, especially ones that you would have to try to sustain over time. I bet your fish will be okay. If you don't feel that they would, you might have to get fish that will do well in your water chemistry, although there is no particular reason to do so if you buy from a local supplier.

 

[Lorna]

Lorna, I would avoid trying to do pH changes, especially ones that you would have to try to sustain over time. I bet your fish will be okay. If you don't feel that they would, you might have to get fish that will do well in your water chemistry, although there is no particular reason to do so if you buy from a local supplier.

I can appreciate what you are saying but I don't think it is a good idea to let the tank PH sit at 8.2. The fish nearly died at one point. I will look at adding Co2 into the tank. thanx again Lorna

 

[sinistral]

Lorna, I would avoid trying to do pH changes, especially ones that you would have to try to sustain over time. I bet your fish will be okay. If you don't feel that they would, you might have to get fish that will do well in your water chemistry, although there is no particular reason to do so if you buy from a local supplier.

I can appreciate what you are saying but I don't think it is a good idea to let the tank PH sit at 8.2. The fish nearly died at one point. I will look at adding Co2 into the tank. thanx again Lorna

Lorna, I would think twice about this. Are you certain that the high pH caused illness or stress? Isn't your pH sitting at 8.2 right now?

If you do choose to pursue adding CO2, you should know that if you use a homemade reactor, you'll be doing maintenance about once every couple of weeks. The amount of CO2 will vary depending on when in the yeast cycle you are (more CO2 put out at the beginning when the yeast is fresh and there is an abundance of sugar, less CO2 put out at the end when the sugar is running out and the yeast cells are aging). Your pH may swing rapidly at those times. You'll also want to calculate your carbonate hardness or KH, because the drop in pH when you add CO2 will depend on your water's KH. The lower the KH, the less ability your water will have to buffer changes in pH. You will also want to install some sort of overflow protection in case the backwards pressure into the CO2 reactor exceeds the partial pressure of CO2 from the reactor. This is typically a very simple check valve.

You might check out this link: here.

Good luck!

 

[Lorna]

Hi sinistral,

thanx for the link. I have lived in NZ for many years and used to own a tropical tank over there when I was alot younger. I never had this kind of trouble with my fish tank as I am having now. I imagine the water must be better over there, prehaps less tampered with. I never worried about PH or even cycling the tank (I didnt actually know anything about it) The fish were all happy.

The only way now that I am keeping the PH down is doing daily H20 changes which I have to because the tank hasnt finished cycling yet. What I am concerned about is that when the tank has finished cycling and I am doing weekly water changes then that is where the trouble will start. As you know the tap water is about 7.4 which I am OK about but when I leave the water for more then 2 days it jumps up to 8.2. Before I bought a testing kit I didn't realise that the PH was so high. The tetras didn't come out they hid, the platy sat near the top and nearly died, the loaches went pale and wouldnt come out and only when I lowered the PH they came out and started behaving normally. The other ammonia, nitrite levels etc were not at all high when the water was first tested.
The fish are ok now because I am somewhat controlling the PH and other levels in the tank through H20 changes. So do you think it is ideal to leave the PH alone at 8.2?

 

[sinistral]

Hi Lorna, thanks for the description of your issues. I understand that you're the closest to the water quality problems that you're describing, and it is your fish, so you have to make the best possible decision based on the available information. Whatever you end up doing, I hope it works out for the best for you!

 

[Lorna]

thanx again sinistral, all the best for you aswell!

LOrna

 

[raptorrex]

I'll deal with the RO question.

RO is a system developed by the US navy, to recycle water in subs. as stated water is forced through membranes, removing most of the stuff except O2. however, this also means any good stuff is lost as well. meaning that you need to make up a cocktail, in order to use the water. you also only get a 1 in 5 return, so water usage will go up!

most often used for Saltwater systems, though some very finicky fish, discus for one, tend to need it in freshwater systems