How to change dosing when upgrading tank?

[hllb]

This week, I transferred the contents of my 32g biocube into a 60g system (plus a 10g sump). I added additional man made rock, but nothing that would consume additional alkalinity. As I’m dialing in the new dosing, would I expect the dosage to be about double because of increased water volume? Or would I expect it to consume around the same since the corals are the same (and actually less coralline algae) and there is more alkalinity available in the water? I’m not sure what to expect. I have seen a drop in alkalinity this week and wondering if it’s due to the larger tank or perhaps I need to recalibrate my doser again.

 

[Randy Holmes-Farley Verified Community Expert]

No, the default assumption with all creatures unchanged is the same dose is needed.

The alk declines half as much in double the volume, and needs the same addition to bring it back.

 

[Dburr1014]

Yes, same amount of coral in more water. Continue the dosing as normal. You could always test more frequently in the coming weeks to verify this as a preventative measure.

 

[hllb]

No, the default assumption with all creatures unchanged is the same dose is needed.

The alk declines half as much in double the volume, and needs the same addition to bring it back.

Thanks, that’s what I thought but have seen a significant drop in the last few days. I’m going to guess it’s a calibration issue so I’ll redo that.

 

[hllb]

I wanted to update this thread in case anyone else seems something similar. When I set up my new tank in December, I very quickly saw a significant increase in alkalinity usage. It was not an issue with calibration of my dosing pumps. In my old tank, my ph ran around 7.75 to 8.0 over the course of the day. I did not have a way to add a CO2 scrubber to that tank, but did have an airstone running with the pump sitting outside.

When I set up the new tank, I was able to add a CO2 scrubber a couple of days later. The pH gradually came up and was running higher. It ended up setting between 8 and 8.15 each day. That bump in pH increased my alkalinity consumption significantly. How do I know that was it? Because I needed to dose PraziPro and I saw my ph drop for about a week (multiple doses) to 7.8 to 7.95. And boom, alkalinity consumption dropped significantly. Just sharing to show what a difference even a relatively modest bump in pH will do for your corals.

I dose with Red Sea Foundation line, liquid. So the dosing levels shown are for that product.

32g Biocube:
Daily alkalinity dosing of 11 mL Red Sea Foundation B
Daily calcium dosing of 3.5 mL Red Sea Foundation A

Transfer all contents (except sand) of Biocube to 65g Tank, adding new man made dry rock and new live sand

Daily alkalinity dosing of 25 mL Red Sea Foundation B (in order to maintain same alkalinity level)
Daily calcium dosing of 11 mL Red Sea Foundation A: This took longer to increase in usage - happened over the course of weeks as shown: 1/27/22 upped to 4 mL: 1/31/22 upped to 5 mL: 2/6/22 upped to 7 mL: 2/20/22 upped to 11 mL per day

PraziPro dosing from 2/17 to 2/23 and noticeable drop in pH

Alkalinity rose from 8-8.5 to 10.3 so lowered dosing to 20 mL per day on 2/25/22
Alkalinity stayed around 10.2 so lowered dosing to 15 mL per day on 2/27/22

Carbon added to remove PraziPro on 2/27

Alkalinity was at 10.1 on 2/27/22 and I expect usage to increase as my pH is trending up now that Prazi has been removed from system. I'll be testing later today so will update then. pH is around 7.95 to 8.05 right now, and I expect within a week it'll be back up to 8 to 8.15.

 

[hllb]

Alkalinity is down to 9.85 today. Once it gets back near 8.5, I’ll start increasing my dosing again.