How to fix Alk/Ca imbalance in a new tank?

tenurepro · Apr 7, 2022

My tank is stuck at alk 7.6 dkh and Ca 460 ppm. I am trying to get alk to 8.2 but adding 100 ml of ESV alkalinity solution to my 7.6 dkh tank led to absolutely no change in alkalinity! Whats happening - is my alkalinity at some kind of saturation point for this level alk?

background. Waterbox 180 tank set up with dry rock (cured for about 2 month) and 80 lbs of caribsea arg-alive special grade sand. The tank was setup with redsea blue bucket salt mixed at 35 ppt salinity. I am trying to harmonize alk and cal between the waterbox and my 6 year old reefer 250, which is at 8.2 dkh and 422 ca. I first tested alk on my new tank on Tuesday (hanna checker with new reagents, validated with my trident), and it was a shocking 6.4. I dosed 100 ml of ESV alkalinity and that raised the alk to 7.6 dKH. (in theory, it should have increased it to about 8). So today i added another 100 ml of ESV alk, waited 6 hours, and tested alk again and it was still at 7.6. Seems like something is precipitating out my alk... what would you recommend i get my two tanks to have similar parameters ?

thanks!

HuduVudu · Apr 7, 2022

You are adding one part of a two part. Don't do that. Add both parts in balance. If you are doing two part you will need to water change. If you your new tank has no load I would use water changes instead of two part to move your alk up. See below.

7.6 is fine for alk. Your tank is new and thus it is creating a lot of acidity as most of your breakdown is aerobic. This is going to hit your alk.

Just relax and don't push numbers. Tanks are different and they have their own equilbriums. If you try to push the numbers you are going to get into a negatively re-inforced cycle. This rarely ends well.

blaxsun · Apr 7, 2022

^ Agreed. If your goal is 8.2dKH you're really not that far off.

Randy Holmes-Farley · Apr 7, 2022

I agree you are not far off, and the current value is fine, but adding an alk supplement will raise alk.

it may just take more time and dosing to attain it. If you want alk higher, just add more.

if you see precipitation, maybe switch to baking soda temporarily.