Please Help Ph Keeps Crashing :(

[Sc0tt8]

Hey guys,

Well i thought my fishless cycle was coming to an end .. Getting Nitrate down to 0.25 after 12 hours..

Problem i've got now though is my PH levels are dropping to around 6 in no time at all..

Last week i done 50% water change, PH was back up to 7.6, but after a week it was back at the 6 mark. This week i done a 75% water change plus a big gravel clean,, again back upto 7.6ish.. After 3 days it's now back down to 6 This isn't helping my cycle one bit, isn't the PH supposed to be at around the 8 mark?

What am i doing wrong? i know the 5ppm ammonia doesn't help.. But is there anything else that can cause this to keep happening? Because at this rate my cycle will never finish..

Is there anything i can add to the water to increase alkaline content?

Ps, my tap water is approx 7.8.

Please help.

 

[waterdrop]

The pH crashing is "good" news! It means your nitrification process is in full swing now and the two beneficial bacterial colonies are almost full size - they are processing like crazy! The reason you can't keep the pH up is probably because your KH is nil and is being quickly neutralized by the nitric acid component of the nitrate(NO3) final cycling product.

Since you're fishless cycling, the perfect answer is to use something that would not be first choice if you had fish, but is fine prior to switching to fish: common kitchen baking soda. Here's how to do it:

This weekend (seems good to me at least!) perform a large 90% water change (that's the other thing messing you up, "percentage" water changes have no purpose if you don't have fish, lol! so make 'em as big as possible, 90% meaning down to the gravel!) and after refilling with conditioned, roughly temp matched tap water, then re-charge the tank with 5ppm ammonia and dose the tank with 3 tablespoons (rough, doesn't need to be exact) of baking soda per 50L of water.

Ideally, you then use a liquid KH test kit to watch the KH you've acheived and watch it drop over the following days. When it passes by 4 german degrees and keeps dropping, then you know its time to dose baking soda again. BUT, you can also just watch your pH and react quicky as you see it drop more rapidly toward 6.2, which is the stall point. Baking soda is a rapidly acting "buffer" (Na-CaCO3 + water.. carbonate and bicarbonate ions) whose ions react with the strong nitric acid component that nitrate produces when its in solution with water. Its a faster and shorter lived method of buffering than the crushed coral method we prefer if we were to have to do it when having fish. In your case though, the approach you should take is to let all this baking soda flush out with the big water change when you get fish and then to -monitor- your stats but not take any pH altering actions unless absolutely forced to do so. Using just water changes to solve a low-pH problem is preferred (drobbyb and I are trying this very month to write up some more about this!)

~~waterdrop~~

 

[drobbyb]

Sounds like you are far along is all. It's pretty common for the pH to drop in the later stages of cycling, especially if you have soft water. Waterdrop has you on the right path here so I'll just get out of the way!

 

[JustFrozen]

what if you're in a fish-in cycle?

i'm having the same prob but i have betta already. since i have hard, alkaline tap water with a high ph, i'm worried that the ph will be fluctuating too much during water changes.

actually i've only had this going for a couple weeks, could it be things i have sitting in the tank?

 

[OldMan47]

With hard alkaline water, you should never see your pH budge unless something in the tank is leaching chemicals into the water. If you are doing a fish-in cycle, you should definitely never see any changes because you will be doing large water changes every day or two that will keep everything but the ammonia at tap water conditions.

 

[JustFrozen]

With hard alkaline water, you should never see your pH budge unless something in the tank is leaching chemicals into the water. If you are doing a fish-in cycle, you should definitely never see any changes because you will be doing large water changes every day or two that will keep everything but the ammonia at tap water conditions.

Thanks for the advice, I appreciate it.

I've got the two things besides the plastic plants (seriously doubt its the plants) in separate containers with tap water to hopefully find the culprit.

Sorry if I hijacked the thread, it was the same topic and I needed to know

edit: a week later, the test showed conclusive results. it was a sunken ship decoration that i bought with the plants long ago

 

[Sc0tt8]

The pH crashing is "good" news! It means your nitrification process is in full swing now and the two beneficial bacterial colonies are almost full size - they are processing like crazy! The reason you can't keep the pH up is probably because your KH is nil and is being quickly neutralized by the nitric acid component of the nitrate(NO3) final cycling product.

Since you're fishless cycling, the perfect answer is to use something that would not be first choice if you had fish, but is fine prior to switching to fish: common kitchen baking soda. Here's how to do it:

This weekend (seems good to me at least!) perform a large 90% water change (that's the other thing messing you up, "percentage" water changes have no purpose if you don't have fish, lol! so make 'em as big as possible, 90% meaning down to the gravel!) and after refilling with conditioned, roughly temp matched tap water, then re-charge the tank with 5ppm ammonia and dose the tank with 3 tablespoons (rough, doesn't need to be exact) of baking soda per 50L of water.

Ideally, you then use a liquid KH test kit to watch the KH you've acheived and watch it drop over the following days. When it passes by 4 german degrees and keeps dropping, then you know its time to dose baking soda again. BUT, you can also just watch your pH and react quicky as you see it drop more rapidly toward 6.2, which is the stall point. Baking soda is a rapidly acting "buffer" (Na-CaCO3 + water.. carbonate and bicarbonate ions) whose ions react with the strong nitric acid component that nitrate produces when its in solution with water. Its a faster and shorter lived method of buffering than the crushed coral method we prefer if we were to have to do it when having fish. In your case though, the approach you should take is to let all this baking soda flush out with the big water change when you get fish and then to -monitor- your stats but not take any pH altering actions unless absolutely forced to do so. Using just water changes to solve a low-pH problem is preferred (drobbyb and I are trying this very month to write up some more about this!)

~~waterdrop~~

Thank you very much waterdrop.. As always