Water chemistry again

[jsoong]

Brian, I learn something new today! I always thought discus needs low pH so never even cosider them for my hard water ...

Joe, you might do just what Brian does, ie. take your soft tap water, add crush coral to get a half decent KH, and let the pH be as long as it is stable. If he can keep discus at 7.8, the high pH shouldn't limit your fish choice!

As far as CO2 goes, have a look at the plant forum. I have no personal experience with CO2 injection, but lots of people have reported stable pH with CO2 injection as long as the KH is > 6 & the CO2 injection rate is not fluctuating. <Some have pH meters hooked up to the CO2 regulator & regulate the CO2 with some sort of feedback mechanism, so there is stable CO2 & pH.>

 

[joe23455]

Dear Brian,
Thanks for your reply. I am a bit confused on one of your points that I think is critical.

Your tap water is >1 dH. very soft just like the water I have with no buffering capacity.

You say you mix this with R/O water. (here is my confusion) Is not R/O treated water very soft? The reverse osmosis has removed the compounds that resulted in the hard water. How can you then mix soft water with soft water and get a GH ~100?? At least that is how I read your message. Sorry if I misinterpreted.


I only have soft water available to me so your approach with the mixing is not on in my case.

I am left with a few options to increase buffering capacity two are below.

1. Use amendments like R/O Right (Kent) in my tank and water changes to hit a target GH and then let the other parameters (pH) float to what ever within reason. The downside is having to use amendments each time. The up side is that you (1) get in the range that you want and (2) at water change time there is not any big difference between tank and "new" water going in so you would have fluctuating GH (etc) with each time.


2. add CC to filter system allowing GH (plus other parameters) to go to some level based on tank conditions and water change timing and amount. This is easy to do. The down side is that you get what you get in terms of GH and other parameters. Perhaps more importantly at each water change I would be adding, lets say 25%, extremely soft water and different pH to a tank that has moderate hardness. This must surely have some impact on tank parameters? Or do you think the buffering capacity can handle this. I think I might actually try and calculate this based on selecting parameters.
Are there other down-sides to using CC?

I really enjoy my sons new tank and they are having a great time watching the fish. I am looking at this chemistry as an interesting theoretical and practical exercise in a small "controlled" system, and am slowly learning a lot. This is just a thought but it seems to me that given the billion dollars plus in hobby aquarium business experience each year it is curious that I cant EASILY pick an approximate hardness range (GH,KH) and pH range that are not near the optimum for my fish and plants. I know that this is in part due to my minimum experience as of yet and that I am dealing with a dynamic living system and how much effort. The fun is in the trying.
I appreciate your thoughts and efforts.
Cheers
Joe



(side note to the couple of people reading this thread- I have tested my pH kit with molecular biology grade ph standards and it appears to be spot on)

 

[jsoong]

I'll comment on #2. Your buffer will keep the pH stable, even with water change.

Eg. In a pure carbonate buffer system with KH of 10 & pH of 8.0 <This just happens to be my tank number>. Now we do a 20% change with pure water. KH is now 8. The calculated pH is: 7.9. The pH change is much lower than you would expect.

 

[TankGirl]

There are too many variables to "dial in" a particular water value and hold it there. In nature, rarely will you see a body of water that is absolutely constant in water parameters. Rainfall, changing seasons, debris entering the water, ect. all impact the system and it is not constant, so don't expect it to be in your tank.

I think you will be satisfied with using CC, as it will bump up your buffering capacity, and as long as you maintain a regular maintenance schedule that involves the same steps each time, the tank should stay relatively stable for our purposes as aquarists. Over time, years, the natural acidification process will want to bring your pH down even lower, so controlling fallen debris is paramount throughout the life of the tank.

There is lots of science involved in this hobby, but it should also be relaxing! I think your fish will do very well in your most conscientious care. Many fishkeepers don't give much thought to what is best for the fish, believe it or not. :?