# Fishless Cycle pH Crash



## zach787 (Sep 19, 2013)

I am in a fishless cycle on a 20 gallon, and all seems to being going well - for the most part. I have been dosing ammonia every four days, and the ammonia is being processed in around 24 hours (for example, from 2.5 to 0 in 24 hours). 

I am in the nitrite stage, with nitrites remaining at 5 for the last several days. However, I think that too is being processed as I now have around 40 ppm nitrates as well (was as high as over 100 ppm before PWC).

For a few days, maybe 4 or 5, nitrites were off the charts (they turned blue initially but then became "clear" with the API test kit). I performed a 75% PWC, and the nitrites returned to a readable level of 5 or so. 

The problem is that my pH has begun to crash consistently, even after large PWCs. For example, I did a 60% PWC yesterday. Tested two hours after, pH was 7.4. Today, 22 hours later, pH was 6.0 or less! I understand that high nitrates can cause a pH crash, and that pH crashes in general can be normal during a fishless cycle. 

Will large, almost daily PWC's to raise pH affect my cycle negatively? I have read that baking soda could in effect raise the pH, is this true? Finally, once the cycle is complete, will the pH likely remain stable? Or can I expect pH crashes after the cycle is done? For reference, my tap water is around 7.6 pH or so. 

Thanks. Someone on this forum a while back suggested I switch to a fishless cycle - it has been going according to plan so far and I am glad I made the switch.


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## coralbandit (Jul 29, 2012)

set aside some of your source water in a bucket with airation if possible.Test it in 24 hours.Often water changes when exposed to enviroment.
This would be the first step to seeing if it is your water or something else taking effect.


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## zach787 (Sep 19, 2013)

OK. I'll do that and post the readings after 24 hours. 

Thanks.


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## zach787 (Sep 19, 2013)

I should also note that the pH had been stable at around 7.6 unti recently even after water changes.


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## jrman83 (Jul 9, 2010)

Your water is too low in kh. Low kh water in the presence of ammonia will drop in ph and it will stay where it bottoms out. Is your home on a water softner system? It is good that you find this out now during your fishless cycle. If that is what it is your best bet will be to get some crushed coral and put in your tanks substrate or in a filter bag and keep it in your tank. This will raise the ph slightly and will bolster kh. Baking soda can do the same but it is much less permanent and will have to be replentished after every water change.


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## zach787 (Sep 19, 2013)

Hi, thanks for the response. 

This house is not on a water softener system, but I know that I have very soft water here on Long Island. 

I do not have a problem with adding baking soda after/with water changes - I plan on doing water changes weekly any way. Despite having to be added every water change, does baking soda have any disadvantages over crushed coral? Also, should I be concerned with GH as well?

Thanks.


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## inkmaker (Jun 10, 2009)

Baking Soda does not add much buffering as would the crushed coral or lime stone. Those add Calcium to the water to increase the Buffering capacity and resist pH swings. In the end, crushed Lime Stone, oyster shell or coral is the best bet for a stable KH and pH in soft water. The CO2 out of the air will bring the pH down with Baking Soda alone in a short while.

All the crushed stuff mentioned above adds Calcium to the water increasing the hardness. That is the Buffering I was indicating.Keep in mind they all work together: CO2 - H2O - Ca++ - pH kH and GH NH4+, NO2-, NO3-, etc.

Your water changes are really the most important. But Buffer it as much as you can.


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## zach787 (Sep 19, 2013)

Alright, thanks everyone for the input. I have decided to try and buffer some with baking soda at least for the remainder of the cycle. I'll see how things go once the cycle is complete and make another decision then if needed in regards to buffering.

Ready for this cycle to be done to finally stock my tank!


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## coralbandit (Jul 29, 2012)

I'd listen to jrmain and inkmaker(and always do!).jrmain has a very good knowledge of water chemistry,and inkmaker is a retired chemist!The baking soda IMO and you needing to replace/replenish will cause flucuations that will cause you unecessary problems and work.A little crushed coral in a filter bag will go along way!


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