Maintaining Alk

Genesis Corals · Feb 8, 2014

I recently did a restart on my tank due to AEFW and Ich. Everything went into QT, the DT was soaked with vinegar and scrubbed clean. New rock and new sand went in and everything is cycled. Corals went back in a week ago after their QT regimen. I use BRS two part with dosing pumps via Apex (Cal and Alk are doesed a half hour apart). I have been having a hard time keeping my Alk around 8.5 like I normally like it, it has been hovering around 7.2. Do new rock and sand absord any Alk? I am baffled as the Cal and Mag levels are holding fine with my old dosing times, but the Alk keeps dropping even though I have almost doubled what it use to be at. Any ideas?

Zero Nitrates · Feb 8, 2014

What kind of salt do you use?

c_healy · Feb 8, 2014

Did you make the rock? Man made rock can eat up alk for a while.

miyags · Feb 8, 2014

I dose cal in the morning and alk at night

redfishbluefish · Feb 8, 2014

The first thing I'd do is to verify your test results. Either have a fellow reefer come over and verify (preferably with some other test kit), or take a sample of water to the LFS and have them test.

If your test results are OK, then I'd look at the actual calcium number. High calcium will drive down alkalinity. HERE is an article that explains what's going on without having any chemistry gobbledygook.

mike007 · Feb 8, 2014

Yes I would double check your test results first. If calcium and magnesium levels are good you may need to increase your alkalinity dose. Your corals are probably using it up faster than you are providing. I went three days without dosing and then tested to determine the loss per day. Then i went to the reef calculator to determine how much to dose to keep levels stable. I have found that dosing 24 times a day keeps everything stable.

Genesis Corals · Feb 8, 2014

Zero Nitrates said:
What kind of salt do you use?

I use Coralife Salt, same as I used before. I like it specifically because of the low Alk number (I believe it comes out around 8).

c_healy said:
Did you make the rock? Man made rock can eat up alk for a while.

The rock is from reefcleaners. Would this type of dry rock do the same thing?

redfishbluefish said:
The first thing I'd do is to verify your test results. Either have a fellow reefer come over and verify (preferably with some other test kit), or take a sample of water to the LFS and have them test.

If your test results are OK, then I'd look at the actual calcium number. High calcium will drive down alkalinity. HERE is an article that explains what's going on without having any chemistry gobbledygook.

I grabbed the refill kit off the shelf for Red Sea and tested with that and it came out the same. My calcium is 450 so I don't think that would cause the issues I am seeing. I had the tank running for a year and a half before this restart and was able to keep my levels stable.

mike007 said:
Yes I would double check your test results first. If calcium and magnesium levels are good you may need to increase your alkalinity dose. Your corals are probably using it up faster than you are providing. I went three days without dosing and then tested to determine the loss per day. Then i went to the reef calculator to determine how much to dose to keep levels stable. I have found that dosing 24 times a day keeps everything stable.

I am almost a 2:1 ratio for Alk:Cal now to keep my levels. Before this restart I had a ton more SPS and I didn't have to dose this heavily, so that is why I am confused. When I first started my tank a year and a half ago I don't think I tested Alk for the first few months, so I didn't know if the issue I am facing is common with new tanks with new dry rock and dry sand. I also dose once an hour (Cal 00:00/Mag 00:15/Alk 00:30).

Any other insight guys?

Spsnut · Feb 8, 2014

I don't know why people don't do all their topping up with lime water?

Genesis Corals · Feb 11, 2014

I really could use some help here, I am at triple the dose for Alk then I was pre-crash. I have a lot less corals now, but can't maintain my levels. Calcium is 410 and Mag is 1360, pH is 8.2 (8.0 low). Any help here would be appreicated. Thanks.

mike007 · Feb 11, 2014

In order to maintain alk. at 8.5 your calcium level needs to be 420 ish. I would recommend raising the alk level where you want it and then try dosing calcium and alk. in a balanced state.

Genesis Corals · Feb 11, 2014

mike007 said:
In order to maintain alk. at 8.5 your calcium level needs to be 420 ish. I would recommend raising the alk level where you want it and then try dosing calcium and alk. in a balanced state.

Thanks for the feedback. I doubt my Alk being off by 10 ppm is the cause of low Alk levels, but who knows. I have raised my Alk to 8.5 but it drops so quickly I can't keep it there. I have been reading that bacteria can use Alk and I wonder if that is the case, but I just don't understand how before the crash I had no problems keeping my levels stable but now it is a big problem.

mike007 · Feb 11, 2014

How are you dosing? I had the same problem and once I got my alk. level were I wanted it I started a dosing regiment where I dose calcium and alk. 24 times a day with a dosing pump and now my levels stay stable.

Genesis Corals · Feb 11, 2014

mike007 said:
How are you dosing? I had the same problem and once I got my alk. level were I wanted it I started a dosing regiment where I dose calcium and alk. 24 times a day with a dosing pump and now my levels stay stable.

BRS dosing pumps via Apex, 24 times a day.

Reefing Madness · Feb 11, 2014

Your not dosing enough. Get that up to 12, and see where it sits after that. I want to know if there is a barrier that it needs to hit before it will maintain. All the numbers I see are quite in line. Get that ALK up a bit higher, lets see if at least we can hit a mark that it will not fall over night.