Alkalinity demands out of control!

[AcanSamDC]

I have a 135 gallon system that I recently moved and took the opportunity to remove a 2" sand bed and convert to bare bottom (I actually used bio tiles to cover the entire bottom). Before and after I dose Kalk during lights out to maintain pH of 8.1.

Before moving the tank I would need to dose 25ml of Alkalinity a night to maintain my desired Alkalinty level of 8.0. My daily alkalinity swing was a little above 0.50.

After a month of stabilizing, the new barebottom tank is thriving and I'm now dosing 100ml of Alkalinity a night. The swing is now closer to 1.0 and I'm struggling to keep Alkalinity where I want it even with nearly 1ml per gallon of Alkalinity a night!

Is it possible there is something in my system that is sucking up the Alkalinity? Could the bio tiles be doing that? Or is it possible my corals are just so much happier that they are just using it up? I don't test N or P, but the new system is clearly waaaaaay lower nutrient, as I am no longer fighting algae at all. I also introduced more white light spectrum and my SPS are certainly growing much faster than before. So maybe it is just coral growth but it's hard to believe.

Here's a photo of the tank a few weeks ago. It did have bryopsis then but that's almost all gone now due to fluco treatment.

 

[Biokabe]

It's possible that you really are just using that much alkalinity, but there is another possibility. In certain conditions (@Randy Holmes-Farley could tell you what those conditions are) some alkalinity mixtures can precipitate out of the water and and the precipitate can accumulate in low-flow areas. The precipitate removes alkalinity from the water, you dose it back in, and then because the conditions are the same it precipitates right out.

If you're seeing noticeably more growth from your corals, I would still think that's the most likely cause of your increased demand.

 

[CHSUB]

Lot of corals. Not a big deal as long as you are not finding “white cakes” where you doses…for example I dose 77 ml of Alk and 478 ml of kalk per night for a 40 gallon system.

 

[AcanSamDC]

Lot of corals. Not a big deal as long as you are not finding “white cakes” where you doses…for example I dose 77 ml of Alk and 478 ml of kalk per night for a 40 gallon system.

My wallet disagrees! At what point do you consider a Calcium Reactor?


The sides of my sump where I dose Alk and then also where I dose Kalk do have some white build-up, but it's just a thin film, not something that protrudes off

 

[Randy Holmes-Farley Verified Community Expert]

What product at 1 ml per gallon?

There is no standard of potency for dosing products.

 

[CHSUB]

My wallet disagrees! At what point do you consider a Calcium Reactor?
Haha and yes.

The sides of my sump where I dose Alk and then also where I dose Kalk do have some white build-up, but it's just a thin film, not something that protrudes off…agreed not a concern.

I ran a cal reactor on my “big” system, (+400 gallons) up front costs are large but once dialed in it was awesome. Not really sure of “a point” when to change but I probably would not where you are now.

Here is mine for reference..

 

[Waters]

My wallet disagrees! At what point do you consider a Calcium Reactor?


The sides of my sump where I dose Alk and then also where I dose Kalk do have some white build-up, but it's just a thin film, not something that protrudes off

Not sure what you are dosing but you can make your own ALK solution with baking soda. Costs pennies to create a gallon jug. That is all I have ever used.

 

[dvgyfresh]

Bacterial growth will eat alkalinity, if you just installed the bio tiles I would expect a large bacterial colonization resulting in alk usage

 

[Randy Holmes-Farley Verified Community Expert]

Bacterial growth will eat alkalinity, if you just installed the bio tiles I would expect a large bacterial colonization resulting in alk usage

What sort of bacterial growth depletes alkalinity?

Normal organic tissue growth (such as bacteria) does not deplete alk.

 

[dvgyfresh]

What sort of bacterial growth depletes alkalinity?

Normal organic tissue growth (such as bacteria) does not deplete alk.

Maybe not directly , but every time I have a bacterial bloom my alk demands would change to increased dosage , could be related to PH / oxygen availability. It happened when I first set up my tanks or do a tank transfer

 

[Randy Holmes-Farley Verified Community Expert]

Maybe not directly , but every time I have a bacterial bloom my alk demands would change to increased dosage , could be related to PH / oxygen availability. It happened when I first set up my tanks or do a tank transfer

Rising nitrate depletes alkalinity. Perhaps that is what you observed when first setting up a tank.

 

[dvgyfresh]

Rising nitrate depletes alkalinity. Perhaps that is what you observed when first setting up a tank.

Likely that is it! When I first started my small 20G all live rock alk would fluctuate daily by almost 2dkh , no corals or fish just rock , now it is stable and fluctuates about .2dkh daily if I do not dose anything

 

[AcanSamDC]

What product at 1 ml per gallon?

There is no standard of potency for dosing products.

Using Red Sea alkalinity. I dose based on my four times a day trident readings. I have just never experienced needing so much alkalinity relative to tank volume.

 

[Seansea]

I am having the same problem. I dose afr. 3 weeks ago was dosing 80 ml/day. Up to 150 now. Did a chemiclean bath 2 weeks ago and since then corralline and corals have gone wild. Happens every time i do chemiclean. Getting expensive tho at this rate

 

[AcanSamDC]

Bacterial growth will eat alkalinity, if you just installed the bio tiles I would expect a large bacterial colonization resulting in alk usage

FWIW, pre bio tile my nitrates and phosphates were way higher. So this coincides with a large drop in both.

 

[Seansea]

I would say in your case removing the sand bed may have something to do with. Sand provides some alkalinity especially if it was an old one maybe corals had to look elsewhere to get the alkalinity