Help... I'm so confused on chemistry

[greatzambesi]

My Fluval Evo 13.5 has been set up for a couple months and everything was going swimmingly. Then I bought a calcium and alkalinity test that were both bad. I will never go back to that store again as we walked to the shelf and 3 of the 5 tests on the shelf were also expired. I went to a different store in town and he tested my water. My calcium was 380 and my alkalinity was off the charts. I did a 5 gallon water change and my alk was down to 10.9. The next day, I did another 4 gallon change and it was down to 9.9. On the third day, I did another 4 gallon water change. This morning, it is off the charts again on alkalinity. There has been no dosing of any kind for at least a week. It was kalk before that when i thought my water was off. The only change was I took the hood off the top of the aquarium and suspended the light for better air/water gas exchange. My ph was always around 7.8. I do use phyto, britewell aminos, and rodifers. I feed mysis. I'm just frustrated because I'm not sure where to go from here. I do have some coral that was all labeled beginner like mushrooms, leathers, rockflower and gsp. I have two clownfish, two snails, three hermits, porcelain crab, and fire scallop.

 

[Formulator]

What exactly is “off the charts”?

There is no biological process I am aware of that will spontaneously create alkalinity out of thin air, so really only a few possibilities I can think of.

1. Your test is wrong or you performed it inconsistently.
2. You introduced kalk again somehow
3. Your salt mix is not mixed well and you did a water change with a batch of saltwater with high alk. Sometimes salt, especially the big buckets, can sediment over time making certain layers higher or lower in various components of the salt. Kind of like all the M&Ms go to the bottom of a bag of trail mix and the raisins stay on top.

 

[Mr. Mojo Rising]

What type of salt do you use? What type of test kit? How are your corals doing?

 

[greatzambesi]

What exactly is “off the charts”?

There is no biological process I am aware of that will spontaneously create alkalinity out of thin air, so really only a few possibilities I can think of.

1. Your test is wrong or you performed it inconsistently.
2. You introduced kalk again somehow
3. Your salt mix is not mixed well and you did a water change with a batch of saltwater with high alk. Sometimes salt, especially the big buckets, can sediment over time making certain layers higher or lower in various components of the salt. Kind of like all the M&Ms go to the bottom of a bag of trail mix and the raisins stay on top.

Thanks for taking the time to respond. I got to the store and watched him perform the test because we both used Salifort. I realized it was user error. For some strange reason I decided it needed to change color from purple to pink back to purple… sometimes I feel smart… sometimes not so much.

 

[Formulator]

Thanks for taking the time to respond. I got to the store and watched him perform the test because we both used Salifort. I realized it was user error. For some strange reason I decided it needed to change color from purple to pink back to purple… sometimes I feel smart… sometimes not so much.

Good news! I can certainly relate to your swings in self perceived intelligence LOL. This hobby does that…

 

[Timfish]

@greatzambesi @Formulator For the record, alkalinity can be generated in reef aquaria by microborers and bioferosion and this can happen faster at lower pH levels (ie higher CO2, increased acidity) and poop also plays a role.

Natural photosynthetic microboring communities produce alkalinity in seawater whereas aragonite saturation state rises up to five

bioerosion, resulting from microbioerosion or biogenic dissolution, macrobioerosion and grazing, is one the main processes involved in reef carbonate[...]

archimer.ifremer.fr

https://onlinelibrary.wiley.com/doi/epdf/10.1111/gcb.17371

https://www.pnas.org/doi/10.1073/pnas.1015895108

 

[Formulator]

Good point. Nitrate metabolism also generates alk, now that I think about it, but considering the OPs situation I thought it unlikely. Poor word choice on my part though.