Nutrient and Alk increase when a tank matures

[arking_mark]

So I have a theory on why some tanks see an increase in Alk and nutrients when they mature.

My tank is just about a year old. Prior to this month, Alk has been pretty consistent and nutrients running very low.

This month my Alk and nutrients have started to rise.

My theory:

1. Substrate and rock have finally absorbed their fill of PO4 --> increase in nutrients
2. Abiotic precipitation of CaCO3 is reduced as rock and substrate surfaces are now well poisoned with PO4 --> increase in Alk

Thoughts?

 

[blaxsun]

Maybe. My alkalinity and nutrients are actually going down though...

 

[Dan_P]

So I have a theory on why some tanks see an increase in Alk and nutrients when they mature.

My tank is just about a year old. Prior to this month, Alk has been pretty consistent and nutrients running very low.

This month my Alk and nutrients have started to rise.

My theory:

1. Substrate and rock have finally absorbed their fill of PO4 --> increase in nutrients
2. Abiotic precipitation of CaCO3 is reduced as rock and substrate surfaces are now well poisoned with PO4 --> increase in Alk

Thoughts?

Could be a coincidence.

#1 looks right. Aragonite surfaces probably become saturated with PO4 and PO4 in water subsequently increases. But what other changes occurred in the aquarium? increased stock? Increased feeding?

#2, not sure about.

Check back in a year and see if the conjectures still makes sense

 

[arking_mark]

So with the uptick in nutrients I've started dosing DIY NoPox:

500ml distilled white vinger
375ml vodka
125ml water

Measured Level (ppm) ....................Daily Dose ml/100 L (25 gal)
NO3 above 10 ---------------------------------------3
NO3 above 2.5, but less than 10 ------------------2
NO3 above 1 but less than 2.5 ---------------------1

I'm dosing 4ml to my 400L which is about 1/3rd the recommended dose. In 3 days, I've see a drop from 15.8ppm to 11.3ppm NO3, and a drop from 0.13 to 0.10 P04.

I'm pleasantly surprised this is working.

I'll continue to monitor to ensure nothing bottoms out.

 

[arking_mark]

So DIY NoPox seems too effective. My nutrients are down to 4ppm NO3 and 0.02ppm PO4. Ive reduced the dose to half and increased feedings...I'm worried that I will have to stop carbon dosing.

 

[SantaMonica]

Carbon dosing is indeed effective and thus can be somewhat dangerous.

I've not heard of mature tanks increasing alk though.

 

[Randy Holmes-Farley Verified Community Expert]

So I have a theory on why some tanks see an increase in Alk and nutrients when they mature.

My tank is just about a year old. Prior to this month, Alk has been pretty consistent and nutrients running very low.

This month my Alk and nutrients have started to rise.

My theory:

1. Substrate and rock have finally absorbed their fill of PO4 --> increase in nutrients
2. Abiotic precipitation of CaCO3 is reduced as rock and substrate surfaces are now well poisoned with PO4 --> increase in Alk

Thoughts?

Those can both be true, certainly, but I do not know if it is the explanation for the observations a few folks have of alk rising. It explains a reduced demand, but not a rise.

 

[arking_mark]

Those can both be true, certainly, but I do not know if it is the explanation for the observations a few folks have of alk rising. It explains a reduced demand, but not a rise.

The rise is due to dosing Kalkwasser and not reducing the drip as demand went down

 

[Randy Holmes-Farley Verified Community Expert]

The rise is due to dosing Kalkwasser and not reducing the drip as demand went down

Then yes, that is a possible explanation.

Other things reduce demand as well, such as organics coating calcium carbonate surfaces, reducing precipitation.