Low pH in cycle?

[Matt_]

Hello all, I have been cycling my 20 gal for nearly 5 weeks now but recently I have been seeing a consistant Ph of 6, the pH is usualy around 7 so why has the Ph dropped all of a sudden?

I tested my tap water and that is at 7.2, I done a 20% pwc today to try and raise the pH but it didnt increase. Not too sure what to do, or is this just expected when cycling?

 

[dalto]

If your kh is low than your ph will drop during cycling.

a 20% water change was probably not enough to impact it.

If you are fishless cycling just add some baking soda to get your ph and kh up.

 

[Matt_]

If your kh is low than your ph will drop during cycling.

a 20% water change was probably not enough to impact it.

If you are fishless cycling just add some baking soda to get your ph and kh up.

I currently don't have a KH test kit so there isnt a way for me to find this out unfortunately, If I was to increase the pH will this be a temporary fix or will it stablise it? also If I was to do a water change what % could possibly impact it enough to increase to atleast 6.5 or greater?

Thanks

It is a fishless cycle btw

 

[Mebbid]

Just do a 100% water change and redose the ammonia. Its no big deal and is expected during a fishless cycle.

 

[Matt_]

Just do a 100% water change and redose the ammonia. Its no big deal and is expected during a fishless cycle.

Ok I'll try and do that tomorrow then , Just wondering will my pH drop when the cycle has finished? Also will a pH of 6 stall the cycle?

Sorry for the ammount of questions still learning

 

[Mebbid]

It shouldnt be an issue if you do regular water changes. But yes, over time the ph will drop without proper maintenance.

Also, yes a 6.0 ph will stall the cycle.

 

[Matt_]

It shouldnt be an issue if you do regular water changes. But yes, over time the ph will drop without proper maintenance.

Also, yes a 6.0 ph will stall the cycle.

I will be doing weekly wc's as expected to keep ontop of the maintenance, would you reccomend doing a 100% water change or use baking soda to increase just the pH? was mentioned above just curious.

 

[Mebbid]

Either will work, personally i would just do the water change.

 

[Matt_]

Either will work, personally i would just do the water change.

Ok thanks, i will be able to lower the NitrAte that has accumulated also

 

[Matt_]

Update:
Earlier today I done the 100% water change, The results after that were

Ammonia: 0
Nitrite:0
Nitrate:5
pH:6.8

I added the ammonia upto 3ppm and then tested later today; The test resulsts were:

Ammonia: 3
Nitrite 0 (still haven't caught it rise)
Nitrate 5
pH: 6.8

Once the ammonia reaches 0 will that be the cycle finished?

 

[Mebbid]

As long as the ammonia drops to 0 after 24 hours with no nitrites then your tank is cycled.

 

[Angela1108]

Sometimes the nitrites are hard to catch/see. If you have nitrates the. It has gone past the nitrite phase


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[Matt_]

Sometimes the nitrites are hard to catch/see. If you have nitrates the. It has gone past the nitrite phase

As long as the ammonia drops to 0 after 24 hours with no nitrites then your tank is cycled.

Ok ill check it again in 24 hours. I'm hoping its at 0 by then And I have tried to catch the nitrites earlier in the cycle and could never get a reading past 0, they are just too fast or my Nitrite test bottle is no good.

 

[ScotJudd]

Hi Matt.
I wouldn't get too hung up on not seeing the Nitrite reading. I have cycled two tanks and never had a nitrite reading but I know for a fact that my tanks were fully cycled. 3ppm ammonia drops to zero in 24 hours and nitrites read zero too.
As for your Ph, I would highly recommend checking the Kh of your water source, mine was less than 1 deg. I use 2.5ml bicarbonate of soda in every 10 litres of source water. This gives me a reliable 6 deg of carbonate hardness and a steady Ph. Other forum members also recommend crushed coral or shell in the filter but I have not tried this myself.



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[Matt_]

Hi Matt.
I wouldn't get too hung up on not seeing the Nitrite reading. I have cycled two tanks and never had a nitrite reading but I know for a fact that my tanks were fully cycled. 3ppm ammonia drops to zero in 24 hours and nitrites read zero too.
As for your Ph, I would highly recommend checking the Kh of your water source, mine was less than 1 deg. I use 2.5ml bicarbonate of soda in every 10 litres of source water. This gives me a reliable 6 deg of carbonate hardness and a steady Ph. Other forum members also recommend crushed coral or shell in the filter but I have not tried this myself.



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I know you just read around that you "should" see a nitrite spike so you somewhat expect it to be there. I haven't got a Kh test kit right now but it seems expected that I will have to raise it , I have spare tray in my bio filter so maybe crushed coral maybe a viable option

when I do get a Kh test kit what hardness level am i looking to trya nd achieve?

Thanks

 

[ScotJudd]

Hi Matt.
I find a reasonable Kh is 6. It stabilises Ph without raising it too high. Raising Kh further will drive Ph higher. As an aside, I keep Gh at about 6 as well. These figures seem to suit my tetra/Cory/RCS tank. Other fish may prefer a higher Gh.
I think there might be a conception that all the ammonia is converted to nitrite, giving a high nitrite reading, and then converted to nitrate. In reality the ammonia is slowly converted to nitrite and the the nitrite subsequently converted to nitrate in a continuous cycle. Therefore the nitrite reading is likely to be low or undetectable. It seems rare that keepers have problems specifically with excessive nitrites (I might be mistaken). Because ammonia is added to a certain ppm it is easy to read. The final stage of nitrates are also easy to measure because they remain until diluted by WCs or plant absorption. Nitrites are part of the ongoing process from ammonia to nitrates and are often very low apart from in the very early stages of starting to cycle your tank, when only the ammonia/nitrite bacteria are in abundance and the nitrite/nitrate bacterial have yet to colonise. If you have used a piece of seeded media from another tank to seed your filter then the chances are that both bacteria are already present and nitrites will not have an obvious spike.


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[Matt_]

Hi Matt.
I find a reasonable Kh is 6. It stabilises Ph without raising it too high. Raising Kh further will drive Ph higher. As an aside, I keep Gh at about 6 as well. These figures seem to suit my tetra/Cory/RCS tank. Other fish may prefer a higher Gh.
I think there might be a conception that all the ammonia is converted to nitrite, giving a high nitrite reading, and then converted to nitrate. In reality the ammonia is slowly converted to nitrite and the the nitrite subsequently converted to nitrate in a continuous cycle. Therefore the nitrite reading is likely to be low or undetectable. It seems rare that keepers have problems specifically with excessive nitrites (I might be mistaken). Because ammonia is added to a certain ppm it is easy to read. The final stage of nitrates are also easy to measure because they remain until diluted by WCs or plant absorption. Nitrites are part of the ongoing process from ammonia to nitrates and are often very low apart from in the very early stages of starting to cycle your tank, when only the ammonia/nitrite bacteria are in abundance and the nitrite/nitrate bacterial have yet to colonise. If you have used a piece of seeded media from another tank to seed your filter then the chances are that both bacteria are already present and nitrites will not have an obvious spike.


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I will be getting a GH and a kh test kit very soon, I'll try and get both around the 6 mark as you suggested; I will also be keeping Cory's, tetras and one pleco I did actually use my old bio filter which was for a tank that was running for 2+ years so that's probably why it was so fast for me, Thanks for the information you given it helps alot!

 

[Matt_]

Another update, I added the 3ppm of ammonia to see if it could drop to 0 within the 24 hours and it dropped to 0.25 but i tested the pH and it was 6 so would have this stopped it from dropping to the 0ppm mark for the ammonia?

would you say my tank has sustaind a complete cycle and is ready or would you say tis still not ready? if i do a water change and add ammonia the pH is just going to drop and stall the cycle so not too sure what to do at this point, any help would be appreciated. Thanks

 

[dalto]

Just add some baking soda. It will raise your ph and kh and keep your ph from crashing during the cycle. Then it should work as normal.

You are likely very close to being done. You may find that after adding the baking soda you are fully cycled.

Don't forget to do a 100% water change after you are done to remove all the nitrates.

 

[Matt_]

Just add some baking soda. It will raise your ph and kh and keep your ph from crashing during the cycle. Then it should work as normal.

You are likely very close to being done. You may find that after adding the baking soda you are fully cycled.

Don't forget to do a 100% water change after you are done to remove all the nitrates.

I just done a 80% water change before reading this, what shall i do add ammonia again? last time i tested it removed 2.75 ppm of ammonia as only 0.25 was left (probably due to the pH crash)