Need help understanding fluctuation of Alk

reefiniteasy · May 9, 2019

I need help understanding why Alk is fluctuating as much as it does while other parameters (Ca and Mg) are pretty constant. I have no livestock in the my 16g BioCube yet. We are on day 16 of the cycle. I used TurboStart and it is pretty much ready for fish.

Here are some numbers:
4/21 - Mg 1350ppm, Ca 435ppm, KH/Alk 10.05dKH
4/29 - Mg 1350ppm, Ca 450ppm, KH/AlK 6.1dKH (water change to bring levels back up)
5/2 - Mg - 1335ppm, Ca - 450ppm, KH/AlK 8.6dKH
5/8 - Mg 1350ppm, Ca 435ppm, KH/AlK 6.85dKH

Why is Alk dropping out every 6-8 days? Is this normal, is this to be expected? Should I do a water change, of let’s say 5 gallons every week to compensate? Or should I start dosing the Alk part of a 2 part system.

I just want to understand more so I can effectively explain to my students that are interested.

sghera64 · May 9, 2019

Alex Sadowsky said:
I need help understanding why Alk is fluctuating as much as it does while other parameters (Ca and Mg) are pretty constant. I have no livestock in the my 16g BioCube yet. We are on day 16 of the cycle. I used TurboStart and it is pretty much ready for fish.

Here are some numbers:
4/21 - Mg 1350ppm, Ca 435ppm, KH/Alk 10.05dKH
4/29 - Mg 1350ppm, Ca 450ppm, KH/AlK 6.1dKH (water change to bring levels back up)
5/2 - Mg - 1335ppm, Ca - 450ppm, KH/AlK 8.6dKH
5/8 - Mg 1350ppm, Ca 435ppm, KH/AlK 6.85dKH

Why is Alk dropping out every 6-8 days? Is this normal, is this to be expected? Should I do a water change, of let’s say 5 gallons every week to compensate? Or should I start dosing the Alk part of a 2 part system.

I just want to understand more so I can effectively explain to my students that are interested.

As this is a new tank, there are likely bio-processes (think organic matter digestion) taking place. Bacteria colonies are covering your rock and other surfaces. Some of these processes produce acid which is neutralized by the alkalinity (carbonate buffer). It should level out at some point.

Do you have a skimmer to help remove some of the undigested proteins and amino acids from the water?

Randy Holmes-Farley · May 9, 2019

I’m on my phone so cannot link easily, but go to my articles at the top of this chem forum page and find one called “why do calcium and alk consumption not always match “. It describes how demand of each is interrelated in great detail.

jent · May 9, 2019

Here is the link: http://reefkeeping.com/issues/2004-12/rhf/index.php

Randy Holmes-Farley · May 9, 2019

Thanks for posting it!

reefiniteasy · May 9, 2019

sghera64 said:
As this is a new tank, there are likely bio-processes (think organic matter digestion) taking place. Bacteria colonies are covering your rock and other surfaces. Some of these processes produce acid which is neutralized by the alkalinity (carbonate buffer). It should level out at some point.

Do you have a skimmer to help remove some of the undigested proteins and amino acids from the water?

I do not have a skimmer. That is the only piece of equipment I don’t have yet. I have been looking at two. The Reef Glass nano skimmer (http://www.reefglass.com/) is probably my best choice because of limited space in the back chambers of the BioCube. I also really like the AquaMaxx 1.5 HOB.

The only issue is, I would have to hang a HOB on the side of the aquarium in the main display. Would there be any negative effects from doing so? So many people say the skimmer is not necessary in a nano aquarium and just to do water changes more often but realistically that is not always possible in the classroom setting. I want a good protein skimmer but I don’t have the money to make mistakes. I need to make the right choice the first time.

reefiniteasy · May 9, 2019

Randy Holmes-Farley said:
I’m on my phone so cannot link easily, but go to my articles at the top of this chem forum page and find one called “why do calcium and alk consumption not always match “. It describes how demand of each is interrelated in great detail.