New tank and alk

[Geoology]

On the back end of cycling my tank (3 weeks). Started testing cal, alk. Cal seems stable 450 but seems my alk drops .2-.3 per day so I have been dosing daily. Just wasn't sure that keeping alk at 8.5 in the early stages was necessary. My ph also drops as alk drops.

 

[HuduVudu]

I think that 7.5ish would be more appropriate. The higher alk is for the ooopsy moments when something happens and you have corals consuming quickly.

 

[BitReef]

I’m seeing a similar thing. My tank is 53 days old. I have 3 fish, no corals, no cuc and no coralline algae yet. Alk drops 0.1 or so a day. Not sure where it goes. I dose a little bicarbonate every couple of days. Eventually I want to run kalk in my ato.

 

[HuduVudu]

I’m seeing a similar thing. My tank is 53 days old. I have 3 fish, no corals, no cuc and no coralline algae yet. Alk drops 0.1 or so a day. Not sure where it goes. I dose a little bicarbonate every couple of days. Eventually I want to run kalk in my ato.

The biological filter produces acid in the conversion from NH3 to NO2. This consumes alk.

 

[BitReef]

Thanks! That is something I’ve never heard before.

 

[Quiverfull]

Hello:

Have a few questions regarding this topic that I can't quite find the answers to given some searching through this forum. Seems reasonable that increasing the bio load would create more Nitrate therefore consuming Alk. I did just dramatically increase my fish load and have been feeding rather heavily. Alk went from stable at 8.5 to 7 to 6.5 over the course of 3 weeks after adding the additional fish.
1. If it is the case that the biofilter is producing acid early on, wouldn't effect pH (mine has stayed stable between 8.43 and 8.6)?
2. If the drop in Alk is related to biological processes, will it eventually stabilize or do you need to dose Alk to keep your parameters in a good range (8.0 to 8.5dKH)?
3. What if your measured nitrates are 0 and your Alk still is decreasing (as is the case for my tank)?
4. Does GFO have any effect? (started this several months ago to keep P04 < 0.1).

Current Parameters: [Alk 6.3 (Salifert), Ca 447 (Hannah), PO4 0.04 (Hannah), Ph 8.48 (Apex probe), Nitrate 0 (Salifert)]

Should I just wait it out or start dosing Baking Soda for Alk? Have just added some new SPS frags and am worried I am going to loose them with the low Alk. Older SPS seem to be doing fine.

I appreciate any thoughts.