pH crashing during fishless cycling

[Exiled]

Hello all, I'm on day 9 (woohoo!) of my fishless cycling. So far, everything is happening on schedual like clockwork..... my nitrites are spiking, my ammonia is getting consumed as fast as I can put it in, and nitrates are rising. Only thing is, my pH is crashing...fast. Is this normal? Can the bacteria survive if it starts to get extremely low? I have crushed coral substrate, and even have a large block of coral in the water to keep the pH at 8.0+ ...which it has been holding at steadily, until today. It's at 7.2 now and falling.

ideas?

 

[mrV]

Can the bacteria survive if it starts to get extremely low? I have crushed coral substrate, and even have a large block of coral in the water to keep the pH at 8.0+ ...which it has been holding at steadily, until today. It's at 7.2 now and falling.

pH 7.2 isn't extremely slow. Why do you want to keep pH over 8? Are you going to keep hard/basic water fishes?

Coral, crushed coral etc.. aren't good way to try to keep pH steady. CaCO3 doesn't dissolve almost at all in neutral or basic water. But e.g. carbonic acid will dissolve CaCO3.

So, if you want to "buffer" pH, use NaHCO3 (sodium bicarbonate = baking soda) to increase KH level. Also pH increases too.

 

[Exiled]

I know that 7.2 isnt low...yet. It's falling rapidly, however, and I don't know how low it will go.

thanks, I'll try the baking soda.

Yes, I'm setting up to keep fish that require high pH and KH.

 

[Exiled]

Well, I added some sodium bicarbonate, it braught up my pH all right, but now I can't read my nitrite tests results because it's interfering somehow with the test. I get a snot color in the test tube -- that's not even a test result color!
Is the sodium bicarbonate going to kill off my bacteria??!!


anyone encounter this problem?

 

[mrV]

Yes, I'm setting up to keep fish that require high pH and KH.

What kind of fishes are you going to keep? What about GH = total hardness?

but now I can't read my nitrite tests results because it's interfering somehow with the test.

Are you sure, you did it ok? I haven't had any problems to get test nitrite while using NaHCO3 and haven't ever heard either. How on earth the test-kit could separate e.g. HCO3- from between crushed coral and baking soda? It's still the same compound. And nitrite test doesn't measure carbonates.

Is the sodium bicarbonate going to kill off my bacteria??!!

No.

 

[Exiled]

I have no idea why the the test has been affected by the baking soda. I used your run-of-the-mill Arm and Hammer. I used about 5 heaping teaspoons -- that's what it took to get the pH to 8.0.

these are the fishes I'm going to keep:
1 male M. Johanni with 3 females
1 male P. Elongatus with 3 females
1 male P. (metriclima) Zebra cobalt (the solid light blue) with 2 females
1 male P. (metriclima) Zebra “Red Top” with 2 females
--or--
1 male Cynotilapia afra with 2 females


my GH is at 6.

That the nitrite test went crazy right after i added the baking soda is weird isn't it?
It's still acting funny. Maybe I should do a water change? I'm more than positive I have a really healthy bacterial colony in there.

 

[mrV]

Ok, you're going to keep malawis.

Here is basic information about lake of Malawi - about water values.

Electricity ~ 240 mS/cm
pH ~ 8-8,5
KH ~ 6-7
GH ~ 4-5

That the nitrite test went crazy right after i added the baking soda is weird isn't it?

Yes, wierd. What kind of test did you use? Tetra, JBL?