Ph Crash, Can't Figure Out Why?

[tunerhead24]

In the middle of my fishless cycle I got a PH crash, I used bicarbonate of soda and that seem to do the trick for the rest of the cycle. After I did the 90% water change I replaced my substrate with eco-complete substrate. I planted a bunch of plants and bought a pressurized co2 system, but before i set everything up i got another PH crash! I have a big piece of bog wood in the center of the tank, could this be the reason for my crashes? Also I know I can use crushed coral to buffer the water, can I leave it inside my canister filter? By the way my tap water has a PH of about 7.4 to 7.6......

 

[backtotropical]

Hi,

I remember being involved in the thread about the previous crash. Did we ever solve what the problem was? Do you just have soft water? (sorry, can't remember)

The bogwood is unlikely to have been the cause. It would usually cause a slow reduction in pH rather than a crash, and even then only in soft water. Bogwood in hard water would usually have no effect at all on the pH.

I note your question about the crushed coral, but won't go into that just now. It's usually best to determine the problem before discussing solutions.

Cheers

BTT

 

[tunerhead24]

Hey BTT how are ya? Well I thought we did solve the problem when I introduced the bicarbonate of soda. My Ph readings from tap water is 7.4, one thing I have to admit but don't think has nothing to do with the carsh is that I never cleaned out the canister filter after the fishless cycle. I don't know what's causing this and I really don't want to purchase any of those PH up liguids, I really don't belive in them.

 

[OldMan47]

If I recall correctly, you have all the symptoms of very soft water. That means that the wood may very well be enough to reduce your pH. I would be favoring some crushed coral in the filter to try to stabilize the pH at 7 or a little above. As you said, dosing with the pH up stuff is not a good idea, it will cause the pH to fluctuate quickly which is the reason we suggested not using baking soda after there were fish in the tank. I would start by using a small amount of crushed coral or crushed shell in a media bag in the filter to try to just stabilize rather than a large amount to try to drive the KH up. If you find you don't quite have enough, you can easily add some more.

 

[tunerhead24]

Any sugestions where I can find some crushed coral, I doubt any of my lfs would have any.

 

[OldMan47]

Go to any fish store and buy a small bag of the light colored substrate they sell for salt water tanks. It is pretty much straight crushed shells and coral.

 

[tunerhead24]

ok i know after adding the crushed coral my Ph should rise (hopefully) back to normal, but wouldnt i be back to square one after i start injecting co2 for the plants??

 

[petertr]

If you have very soft water, the CO2 can be the cause of the crash.

Carbonic Acid is about pH 1

 

[OldMan47]

If you are careful to measure the pH before you add in the CO2, you can judge how much pH you get from adding the CO2, you can take that into account when you allow the effect of CO2 in your water. The essence of it is that you must take into account that about 1 unit of pH comes from the CO2. That means that you are trying to keep pH at less than 7.0 before you adjust for CO2, you need a pH of 6.0 with CO2. The CO2 effect is considered to be not an issue as far as fish are concerned. Although CO2 affects your pH, it is not the real concern addressed by people who worry about pH. The real effect of varying pH is that it often reveals an underlying problem with total dissolved solids, that is a real problem when it is present.

 

[tunerhead24]

well i got my hands on the crushed coral, i put it in a media bag i found at my lfs and dropped it in my canister filter. I checked the PH levels the next morning and i now have a reading of 7.0, after that i set up my co2 system and added all my plants and did another test which gave me a reading of 6.6. Im guessing everything should be fine, im thinking about adding the fish tonight.......