How To Prevent A Ph Crash......

[pseud]

Well, some of you saw in my evolution thread that I added a large piece of wood. Right before I went to bed the Aqua-Gods shined upon me and reminded me that the wood will lower the pH of the tank. Not wanting it to crash over night I DCed the CO2. Sure enough, first thing this morning the pH is 6 and KH between 1 and 2 degrees.

Now switching my CO2 on is gonna drop my pH probably to about 5.8 maybe even 5.6
I'm not sure I'm comfortable with my pH being this low. I don't really understand about buffering. So what can I do to ensure switching my CO2 on wont cause any problems.

(I'm using DIY CO2 by the way - 1tsp yeast, 4cups sugar, 2l soda bottle)

I think I read somewhere that adding 1 tsp of baking soda per 50gallons will raise the KH by 1 degree....

 

[RYO]

Ph that low wont matter much as long as its a gradual drop. As long as your fish are happy (see them smile)
your ok.
I buffer my water with bicarb, my kh is around the same as yours. I use 1 teaspoon every water change which gives me a kh of around 4 and ph between 6.6 and 6.8 (tank is 120L). So your estimate for the 50g is about right.
Add a teaspoon at first then take a reading next day and build up your kh gradually. You'll soon suss out how much to add every water change.
Hope this helps

 

[zig]

Thats right pseud you use baking soda (bicarbonate of soda) not baking powder, heres a calculator that will tell you how much to add, well auctually this calculator is apparently out by 6%, but hey in the overall scheme of things........it aint much.

If you dont want to use the calculator 1 teaspoon of bicarbonate of soda will increase the KH of 50 litres (13 US gallons) by 4 degrees or 68ppm (cant remember how many teaspoons in a tablespoon)

Edit: better put the link in

http/dataguru.org/misc/aquarium/CalKH.as...&EKH=&pHChange=

Thats better

 

[pseud]

Awesome, thanks for that guys.. that link to the calculator is cool... Bookmarked it.

(I think it's 3 tsp to the tbsp)

I added 1 tsp and it did the trick. Brought my KH and pH up. CO2 hooked back up!

 

[pseud]

Hey, Zig.. or anyone.. I understand the KH-pH-CO2 relationship, but I KEEP reading this term buffering, and can't come to terms with it... what exactly does it mean 'to buffer' the water?

 

[littleimp]

'To Buffer' the water means to add enough alkalinity to the water to conteract a PH drop.

'The buffer' absorbs the offending problem before it gets to the acidity to drop the PH

In laymans terms that is!!


Good way to look at is fish food.

fish=alkalinity
contamination=PH

You add 2 pinches of food to your tank no matter what. (as in your water content)
You have 10 fish that can eat this food before it contaminates the tank. This is your buffer = PH stable
If you add another 5 fish (=15fish) you know have an excess of buffer to eat the food = ph rise
If 5 fish die (=5fish) the excess food is now going to contaminate the tank = ph drop

Their is also an equation in the matter concerning magnesium but in a freshwater tank this is minimal enough to be ignored. In a saltwater tank though this is important as no matter how much bicarbonate you add it won't raise your KH. This is where balanced additives come in.

Check this out for more info.

http/andy-hipkiss.co.uk/

 

[modernhamlet]

Well, some of you saw in my evolution thread that I added a large piece of wood. Right before I went to bed the Aqua-Gods shined upon me and reminded me that the wood will lower the pH of the tank. Not wanting it to crash over night I DCed the CO2. Sure enough, first thing this morning the pH is 6 and KH between 1 and 2 degrees.

Now switching my CO2 on is gonna drop my pH probably to about 5.8 maybe even 5.6
I'm not sure I'm comfortable with my pH being this low. I don't really understand about buffering. So what can I do to ensure switching my CO2 on wont cause any problems.

(I'm using DIY CO2 by the way - 1tsp yeast, 4cups sugar, 2l soda bottle)

I think I read somewhere that adding 1 tsp of baking soda per 50gallons will raise the KH by 1 degree....

Yup. I would be really afraid of having a planted tank with co2 injection and driftwood that had a KH of 1 or 2. Buffering the KH up to 4 or 5 with baking soda will increase your pH, but will buffer against further dangerous drops. Have you considered CaCO3 (and possibly MgSO4)? Those can provide the KH buffer without the pH swing.

Just some thoughts to consider...

 

[pseud]

Thanks... this is making more sense now...kinda.. lol

Those can provide the KH buffer without the pH swing.

I like the idea of that. Adding the baking soda worked but I'm really nervous about the tank. I don't like these pH swings... and with weekly water changes thrown into the mix, that makes things even worse. It makes it hard to keep things constant.

I dunno. I need help. What would you do?

 

[AndyTaylor]

Pseud, i'm having the same problems at the moment:

KH 20
PH 6.5
CO2 10ppm

Need the CO2 to hit 30ppm so i've increased my co2 mix.....now i guess my ph will drop so i've buffered with 5ml (tsp) bicarb. According to zig's link i need to add 1.78 tsp bicarb to buffer the water sufficiently?

Can i add this all together or do i need to bring it up slowly? and how long does the buffering effect last? does it get used up?

Sorry for the hijack, thought i'd add to the confusion!

Andy...starting to feel like i bought a chemistry set and not a fishtank!

 

[pseud]

Andy - I have no idea lol. I wouldn't have buffered with a KH of 20, but then, I don't think I know what I'm doing anymore .

On top of that, I've deduced that these test kits suck balls. I used the calculator above, which has got to be correct. It's just mathmatics. Tested my water, added 1/4tsp of baking soda and got WAY higher results than I expected. I read it correctly, tested correctly. So the only thing to assume is that the tests are totally inaccurate. I'm not buying new ones either. Screw it. I'm doing this with my sixth sense from here on out. (and maybe a little use of the pH kit just for a little hint as to where the figures are at).

Anyway.. I hope someone can help you Andy....