Confused...

[Tom Stevens]

Hi,
I started using Kalkwasser 1 week ago after adjusting Alk to 8 and Calcium to 420. My PH goes from 8.05 in the morning to 8.28 by the evening. I measure Alk every night. I use a Littlefishies Kalk reactor and it seems to be working as designed. Based on my evaporation of 1 to 1.5 gallons a day I put in 3/4 cup of BRS Kalkwasser in the reactor. I have only about 8 frags of softies and LPS. I thought that the Kalkwasser would be able to keep up with Alk and Calcium, but I find myself having to dose about 100 ml Sodium Bicarbonate every couple of days and Calcium Chloride as well. I am scratching my head. What can be using all of Calcium and causing the Alk to go down? I use Hanna to check Alk and validated results with RedSea. I use RedSea for Calcium test. The tank is 3 months old. I started using Kalk more as a test drive and fully expected to turn off until I have more coral. Having to dose while using Kalk is unexpected. I used dry Marcos Rock... can that be influencing the numbers? All the corals seem fine. Any thoughts?

75.2 Waterbox cube
Bubble Magus curve 5 skimmer
2 Ecotech 15w pro at 40%
A fan pointed at surface to keep temp down between 78 - 78.5

 

[ihavecrabs]

I'm confused too.

I will say, I attempted to use kalk for my coral frag quarantine tank and I was very surprised the amount it took to raise alkalinity... Much much more than I would have thought.

Check out this kalk calculator

https://www.hamzasreef.com/Contents/Calculators/KalkContribution.php

I will also say, since you started with dead rock, I have experienced rock absorbing/lowering alkalinity in previously set up tanks. It took a lot of dosing to meet the equilibrium and as soon as it did, the alkalinity spiked. So test very often if it is a new tank.

 

[Reefahholic]

I bet it’s that dry rock. Sounds like a headache.

 

[chipmunkofdoom2]

Assuming your reactor is producing 100% saturated limewater, at 1 gallon per day, you're adding about 1.6 dKh of carbonate alkalinity. Dosing an additional 100 mL of bicarbonate solution, assuming you mixed it using BRS or Randy's instructions, adds about another 1 dKh.

So assuming you hand-dose bicarb every three days and use one gallon of fully saturated limewater per day, your tank is consuming about 1.9 dKh per day in alkalinity. This is on the higher end of normal, but I don't know if I'd call it abnormal. Especially in a new tank where abiotic precipitation could be contributing to the consumption.

Do you test for magnesium? Is it sufficiently high?

 

[Tom Stevens]

Thank you for the information. Yes, I followed Randy’s recipe so your calculation should be correct. I checked Magnesium 5 days ago and it was 1400. I will continue to monitor closely. This information relieves some of my worry.

This reef tank has become an obsession (in a good way).