Ph Crash During Fishless Cycle

[Emily in CA]

I am going through exactly the same thing with a 45 gallon tank fishless cycle. I am beginning my third week of the cycle using ammonia (10% ammonia hydroxide from ACE Hardware) and bacteria from my pond filter and all of a sudden my PH has crashed (6). I just did a partial water change and my PH came back up to 7. My nitrites are 2ppm and nitrate is 5 ppm after the water change. I have read that ammonia hydroxide can mess with the ph. Will baking soda cause other problems if I use to raise the ph?

Welcome to TFF ! I was just about to ask the same question also how much baking soda should I use and can I use the arm & hammer brand?

Thanks! I know that raising or lowering PH suddenly can hurt fish, but I am not sure if it will also affect bacteria. I know you are supposed to raise or lower PH very gradually but I am not sure if that applies when you dont have fish in the tank yet.

 

[waterdrop]

No, neither of you needs to worry. Big pH swings and small percentage water changes are all about *fish*, not bacteria! When you do water changes during fishless cycling (if you -have- to...) then it always makes sense to make them as large as practical, either 90% or maybe a little less if you don't want to turn your filter off and have to reprime it. Then you always recharge with ammonia of course.

Baking Soda (NOT baking powder) can be used pretty freely once you get the hang of it, although if water changes will bring your pH up then usually that's better. To give you an idea, a tablespoon is often a good rough starting amount for around a 30gallon tank. Having a KH test kit makes it much easier to use baking soda. You want to get your KH up around 4 or above so that you don't have to add the baking soda too frequently.

When the end of fishless cycling comes, the baking soda goes "out with the bathwater" so to speak and you never use it again. Ideally your tap water changes will take care of your tank from then or or if you are forced to raise pH, it will be done with crushed coral in bags in the filter, but you should only undertake this if forced.

~~waterdrop~~

 

[OldMan47]

In extreme cases, it can be necessary to add materials to raise KH after the cycle has finished and in those cases it is safer to use something like crushed coral. Sodium bicarbonate can still be used but it is much more dramatic than using something like the calcium carbonate in the coral.

 

[tunerhead24]

I did another 50% water change today and my PH came back up to 7.6 I topped off ammonia to 5 ppm again. Im going to wait 12 hours till I do the next water test....... so I'll let you guys know the results of everything els tomorrow

 

[Emily in CA]

No, neither of you needs to worry. Big pH swings and small percentage water changes are all about *fish*, not bacteria! When you do water changes during fishless cycling (if you -have- to...) then it always makes sense to make them as large as practical, either 90% or maybe a little less if you don't want to turn your filter off and have to reprime it. Then you always recharge with ammonia of course.

Baking Soda (NOT baking powder) can be used pretty freely once you get the hang of it, although if water changes will bring your pH up then usually that's better. To give you an idea, a tablespoon is often a good rough starting amount for around a 30gallon tank. Having a KH test kit makes it much easier to use baking soda. You want to get your KH up around 4 or above so that you don't have to add the baking soda too frequently.

When the end of fishless cycling comes, the baking soda goes "out with the bathwater" so to speak and you never use it again. Ideally your tap water changes will take care of your tank from then or or if you are forced to raise pH, it will be done with crushed coral in bags in the filter, but you should only undertake this if forced.

~~waterdrop~~

Great to know - thanks for your help. I have not have issues with PH in the past in my other 10 gallon tank (or my pond) so I am assuming it is the fishless cycle causing the fluctuation. I will use baking soda to raise it if needed. It seems like the ph goes down after the ammonia is processed. I m,ight have set myself back a little with the water change but I will live with it.

 

[waterdrop]

Sounds good Emily. Tunerhead, remember it all takes patience. Lots of stuff happens when you do a water change during fishless cycling. The patterns of all the substances you've been measuring get changed simply by the dilution, the bacteria often pause in their processing because their environment has changed, so sometimes you just have to keep steadily recording your log entries of your measurements and eventually the progress will bounce back into view!

~~waterdrop~~

 

[tunerhead24]

Just did a water test after a 12 hour wait, everything seems to be working! I really believe Im two steps from the finish line! The only thing wrong is the PH is still at 6.4 but I don't think thats doing any harm to the bacteria because its all working perfectly. Here are the stats.......

NH4 - .25 ppm
NO2 - 0 ppm
NO3 - In between 5 ppm and 10 ppm
PH - 6.4

Im going to top off ammonia to 5 ppm and wait 12 hours to see if the PH level really has an affect on the bacteria. I never really got a chance to see if the PH has really been doing any harm because I would always do a water change and raise PH when I top of the ammonia, the cycle has not stalled at all.

 

[waterdrop]

Good, that's great! Its never a black and white thing and "stalling at 6.2" is just an estimate of sorts that we've settled into when talking about it here in the beginners section

~~waterdrop~~

 

[tunerhead24]

Just tested the water and it looks like the ammonia process slowed down a bit, but i guess its going well.

NH4 - 1 ppm
NO2 - 0 ppm
NO3 - 20-40 ppm
PH - 6.4 ppm

 

[tunerhead24]

It's official my fishless cycle has stalled!

NH4 - 1ppm
NO2 - 0ppm
NO3 - 20-40 ppm
PH - 6.0 or less

By the way this test was done 12 hours after the last one I'm going to plan B the dreaded baking soda!

 

[tunerhead24]

Today I added one and a half table spoons of baking soda and raised the PH levels to 7.4 from a 6.0 . I didnt add any ammonia because it still has a 1ppm reading, I hope this will cure the problem. Well I'll keep you guys posted.

 

[waterdrop]

Did you add the baking soda and ammonia after a water change? Usually that method gives the low-hardness tanks like yours a better kickstart if they stall. Regardless, its good that you've seen a very definite rise in pH. If you don't have a KH kit, then you will have to be more sensitive to declining pH and use more baking soda early enough to ward off a stall.

~~waterdrop~~

 

[backtotropical]

You seem to almost certainly have water with a low kH. As Waterdrop says, just keep an eye on the pH, and if it starts to drop at all, add more baking soda.

Keep us updated.

BTT

 

[tunerhead24]

This morning I checked my water stats (6:00 am) and here is what i got...

NH4 - 0 ppm
NO2 - .25 ppm
NO3 - 5 ppm
PH - 7.6

I topped off ammonia to 5 ppm and waited another 12 hours, after the wait everything seems to be back to normal! Wow I would never have guessed the PH levels can have such an affect on the bacteria! This water test was taken exactly at 6:00 pm

NH4 - 0 ppm
NO2 - 1 ppm
NO3 - 10 ppm
PH - 7.6

I just topped off the ammonia back up to 5 ppm I'll keep you guys posted.......

 

[waterdrop]

Lookin good Tunerhead!

~~waterdrop~~