What am I doing wrong??

[9supratt4]

My 180 is completely cycled. There is all base rock in there with Live sand. The SG is 1.026. But my alkalinity is still low. It's been slowly creeping up. It was at 4 dKH now its at 7 dKH. I am using Kent Marine Supperbuffer to raise the alkalinity.
I never had this alkalinity problem until I started using RO water.
PH is 8.3, Magnesium is 1360.
What am I doing wrong?? Especially since there aren't any corals, snails or anything in the tank right now that would use up the alk.
I use Instant Ocean Reef Crystals salt.
Am I going to have to deal with low alk with every water change??
I've talked to people on here that don't use any additives. How do I get to that point??

 

[m0nk]

What kind of sand do you have? Aragonite based sand helps buffer pH and alk because it slowly dissolves over time and is basically calcium carbonate.
Also, it's possible that the salt you use has low alk to begin with. I use Red Sea Coral Pro and keep mine at a salinity of 35ppt (about 1.026 SG) and the alk is usually around 6 dKH when mixed. I do buffer occasionally, but I also have aragonite sand and it helps a lot. I don't have any issues keeping mine between 7 and 9 consistently. HTH.

 

[9supratt4]

I think my sand is aragonite sand. It's the Carib Sea Ocean Direct Caribbean Live Sand.

 

[9supratt4]

That's it?? No advice from anyone else??

 

[mcbdz]

I would check the new water before a water change and see what those readings are. If they arre good Just may need to do frequent changes for awhile.

 

[coraljunky]

I would start with testing a freshly made batch of salt water. Are you using just ro or ro/di? How high is your calcium? High calcium can drive/keep alk down.

 

[9supratt4]

So I got home today from a business trip in Dallas and I mixed up a 5 gallon bucket of new saltwater. I tested the alk and it is 8.
So how does a tank that has no living organisms, but is cycled and no lights use up all that alk??

 

[coraljunky]

What is the calcium in your tank?

 

[9supratt4]

Give me a minute.....I'll go test calcium and magnesium right now.

 

[9supratt4]

Calcium - 380
Mag - 1270

 

[coraljunky]

How long has the base rock been in the tank? How much base rock? How long has the tank been running? I'm having a difficult time seeing low alk and a ph of 8.3

 

[9supratt4]

Originally Posted by coraljunky
http:///forum/post/2829014
How long has the base rock been in the tank? How much base rock? How long has the tank been running? I'm having a difficult time seeing low alk and a ph of 8.3

You and me both!! I'm so confused!!!
The base rock has been in there since day 1, which was about, about 2-3 months ago. There is about 150 lbs if not more.

 

[coraljunky]

Do you have any other source for testing your water......as in another kit or local reefer or store. I find the results a bit off.

 

[9supratt4]

Well the alk is ok now since adding superbuffer. I don't remember if I tested the PH while the alk was that low.