Ph Crash!

[JoshH]

Carried out daily checks today as usual on my fishless cycling tank, ammonia had processed in 12 hours as usual and nitrike has still spiked, thought to check my PH and its fallen from 7.5 down for 6 or possibly lower absolutely no idea what I should do now, would a large piece of bogwood drop the PH that much?? Cant think of anything else that ive done differently etc, would a big waterchange help?

EDIT - Just checked my KH only using the test strips (gotta get some use out of them!) and it shows very low 0 or just above...would having nutrafin co2 kit have caused this? My KH was originally 6 at the begining of the cycle.

 

[Dave Spencer]

Is that a pH crash? Do they really exist?

I run pressurised CO2 in water with a negligible KH and the pH is around 6.

Just remember that the kits we use to test are crap. Go by what your fish are telling you. pH will be relatively unimportant for most fish.

Dave.

 

[doresy]

Hi, the end of the cycle produces acidic conditions and yes a piece of bogwood can and will do it. My tank twice dropped to 6 pH and that was due to a chunk of bogwood I chucked in. Now its a steady 7.4 since it's removal and waterchange

 

[jackson 10]

dont worry to much bye it mate my ph droped from 7.4 to 6 due to i put bogwood in after a 20 % waterchange a couple of days later my ph was back to 7.3 and its still that now with it in there

 

[SharonCC]

I'd try and find out what's causing it...the fluctuations are harmful to fish.

 

[JoshH]

Cheers for the replys, would it just be because it's mid cycle? Or because I'm injecting carbon? I've fully planted the tank today so that co2 should be being used up...is that what causes low KH? too much co2? I've also removed the bogwood and done a large (80-90%) water change and PH seems to have returned to 7.2 for now..!

 

[waterdrop]

Bogwood can definately drive your pH down. If you are running a lot of plants and a CO2 kit then traditional fishless cycling like we discuss in this section may be very hard to carry out, or at least very slow to happen. If that is the case and your tap water is a significantly higher pH then water changes with an ammonia re-charge might be in order throughout your fishless cycle, or you may find that your plants are doing such a good job that you could basically begin a fish-in cycle with the same effort.

In traditional fishless cycling, with medium, few or no plants, a pH of 6.2 or lower is called a "stall" because that is the pH at which the beneficial nitrification bacteria will stop dividing and building large biofilms in the filter. Below about 5.5, these bacteria will sometimes die off. A pH of 8.0 to 8.4 has been reported as the optimal range for maximum growth of these particular two species. Many fishless cyclers (again, traditional, without the planted complication) will optimize the environment temporarily for the bacteria by using baking soda to raise the hardness of the water, raising both KH and pH. This is done up until, but not after the large water change when fish are introduced.

A planted tank is significantly different in that typically, I believe, a much smaller bacterial load will be established due to the plants being in competition with the bacteria for food. In a sense, the healthy maintenance of the plants becomes a functioning aspect of the biofiltration of the tank. If too many plants fail too quickly the tank can experience a "mini-cycle" just like a bacterial biofilter becoming "uncycled."

~~waterdrop~~

 

[JoshH]

I'd say it was medium planted waterdrop, certainly not full of them! Guess is wrongly used the fully planted term..i just meant planted with all that I plan to Thin layer running along the back, and few foreground plants is pretty much it right now..although today I did record my first drop to 0 in nitrite...could that possibly be caused by the plants? Or just a coincidence..i hope the latter as it's another nice point to have reached in my cycle

If only I'd of thought before I ordered the plants it could affect my cycle!! Guess I could remove them!

 

[waterdrop]

Sounds like you're feeling a traditional fishless cycle is still the way to go and it sounds like not enough plants to interfere with that too much. It also sounds like you have a reasonable chance of keeping the pH under control via water changes. This is probably a reasonable approach but you'll have to build up some time and trends to see how long a water change will keep you up before you drop close to pH=6.2 or lower. The potential problem is that if the KH=0 reading is close to correct and adding the pH=7.2 tap water only keeps it high for a day or two then your fishless cycle may hardly progress, as each large water change will cause about a day of "pause" in the cycle usually.

In that case you'd have to consider going to baking soda to raise the KH, but its going to be better if you can just do it with occasional water changes, so I'd go with that for now and just be sure you log everything a lot and talk to the members about what's going on.

~~waterdrop~~

 

[OldMan47]

Josh, if you are injecting CO2 to get 30 ppm, like plant people will suggest, the pH drop is about 1.0. That means that the change from 7.5 to 6.5 would be due solely to the CO2 injection itself. The slightly acidic reaction of moving ammonia through to nitrates could easily account for the rest. The part attributable to CO2 is said to not affect the fish so I would not worry too much about the change, much as Dave said.