Alk & Ca in Reef Crystals

[chunkysoup56]

Hello!

I recently started testing for alk in my 90g and got the following for my tank:

Alk= 6.85 dKH
Ca= 475
sg= 1.026


I was some what concerned about the low dKH so I tested my newly mixed water (Reef Crystals) and got the following:

Alk= 10.1
Ca= 480
S.g= 1.026
Any thoughts on why the Alk would be so much lower???? Only corals I have at the moment is a small frag of Xenia and zoas. All tests were performed with Salifert kits.

 

[C. Eymann]

Using a bucket of salt? maybe settling happened during shipping, give it a few shakes/roll it around a bit.

 

[bryanfuel]

Could be coralline

 

[Randy Holmes-Farley Verified Community Expert]

Even a soft coral tank can use 2 dKH per day through various biological and abiotic processes. Coralline, tube worms, shells of snails, sea urchins and lots more use alk and calcium.

 

[muzikalmatt]

How often are you doing water changes, and how much are you changing at a time? It sounds like your usage is outpacing the ability for water changes up to keep up. As Randy and bryan mentioned, there are plenty of other things that suck up alk/calc in your tank. You could try increasing the frequency and/or amount of water you're changing, but if that still doesn't keep up you may need to start dosing.

 

[chunkysoup56]

Even a soft coral tank can use 2 dKH per day through various biological and abiotic processes. Coralline, tube worms, shells of snails, sea urchins and lots more use alk and calcium.

Thanks! After further testing, it looks like I’m using 1dKH every 2-3 days, but my calcium is staying relatively high (above 465). Would you recommend dosing ONLY Alk until I see the calcium start to drop????

P.S. I would be using BRS two-part

 

[jordan9095]

Thanks! After further testing, it looks like I’m using 1dKH every 2-3 days, but my calcium is staying relatively high (above 465). Would you recommend dosing ONLY Alk until I see the calcium start to drop????

P.S. I would be using BRS two-part

dial in Alk & then dose the same amount of CA. that should work but test to confirm CA is not going up

 

[Randy Holmes-Farley Verified Community Expert]

dial in Alk & then dose the same amount of CA. that should work but test to confirm CA is not going up

That’s a good plan. The calcium should be stable