Yet another ALK question

[MexiReefer]

Hi guys, any help (education) will be appreciated. I setup a 35 gallon system two and a half months ago. It is fully cycled now and it is inhabited by a couple of crabs and 5 snails, and my intention is to get into SPS eventually, no rush.

I have an ATO that replaces around 4.5 gallons per week, probably a bit more.

I am using Tropic Marine Bio syn biotic.

I have been monitoring my levels and making 10% of water changes weekly. My question is regarding ALK levels. The reading has been decreasing from 7.2 to 6.2 in the last 10 days. As I understand there is nothing within the tank consuming ALK or calcium, so I do not understand why is it decreasing in spite of the WC. Do I still need to spike the top off water/tank directly with a buffer to mantin a ALK of at least 7.0. I know that I currently do not have any organism that requires it, but I would like to have stability in the parameters prior to adding any coral, and most importsnt learn how my tank uses/deplates alk, et al.

The current parameters as follows:

Temp. 77
pH 8.21
Alk 6.2 (Salifert)
Ca 415
Mg 1245
NO3 1.0
PO4 0.0

Let me know if can give any other information.

 

[Undertaker]

I just switched to Tropic Marin Pro Reef about a month ago "FIRST BUCKET" and am having the same issue as you. I'm going back to red sea blue bucket or reef crystals.

 

[MexiReefer]

Thanks Undertaker. This is useful.

 

[merereef]

Thanks Undertaker. This is useful.

Do you have a lot of coraline algea?

 

[MexiReefer]

None yet

 

[merereef]

A new tank takes about 6 months to stabalise properly.. sometimes during this period alkalinity can drop fast because of this.. i wouldnt worry too much just dose again to raise alk back up and see if it depletes again. This happened to me aswell and i dosed to being levels back up and its been fine since

 

[GoVols]

None yet

On your next new saltwater that you mix.
Shoot for .35 ppm in salinity and test that batch before your water change.

The alk in TM-Bio used to be at about 8 - 9 dkh.

I'd hate to bash the mix, before you ruled it out.

 

[MexiReefer]

Ok. I justed tested it. With the Salifert it shows a 7.7 alk on a one week old batch of the mix. It does not seem to be the problem.