Chronic Low Alk

[sen5241b]

I always do 50% water changes and spike the change-out water with cal and mag. After the change my cal is over 450 and the alk is normal. It only takes a couple weeks for the alk to drop close to 5 dkh but then it seems to stay there forever. I can dose with baking soda but raising alk to to 7 makes my softies cringe, especially mushrooms. Can my SPS live with this low alk? If not why is dosing to get higher alk making my softies cringe? Is my water change method related? I've heard dosing to raise alk can make cal drop, true?

[gmerek2]

I bet you are raising the alk too rapidly.  I have noticed my softies like the alk but not when I raise it rapidly. A 50% water change should swing that alk level quick shocking them.

[gmerek2]

Alk dropping quickly to 5 in two weeks is pretty normal for me with no dosing in between. But I dose now with Kalk and as needed baking soda. I think the SPS could survive at 5 but thats living life on the edge and you probably wont see rapid growth in the SPS. I would do smaller but more often water changes. I think over dosing alk can cause calcium to precipitate but thats a question Tom can answer.

[sen5241b]

I bet you are raising the alk too rapidly.  I have noticed my softies like the alk but not when I raise it rapidly. A 50% water change should swing that alk level quick shocking them.

 

 

Although it would seem to make sense that a 50% can shock my corals, they always look better after a 50% change out and I have done more 50% changes then I could ever recall. . When dosing with baking soda, I raise it over the course of 2 or 3 days to about 7.

 

There is something weird with my chemistry.

Edited January 29, 2014 by sen5241b

[YHSublime]

Does everything look ok at 5? If so, why change anything or chase numbers? This was brought to my attention by Zygote, and it makes sense. There is nothing in your tank that I know about that you need to dose for. Water changes should meet all your current needs.

 

I keep in between 6-6.5dkH. I have a good range of SPS and LPS FWIW.

[sen5241b]

Does everything look ok at 5? If so, why change anything or chase numbers? This was brought to my attention by Zygote, and it makes sense. There is nothing in your tank that I know about that you need to dose for. Water changes should meet all your current needs.

 

I keep in between 6-6.5dkH. I have a good range of SPS and LPS FWIW.

 

Everything looks fine at 5.  Does your SPS grow at 6 dkh? If my SPS are fine with low alk then so am I.

[Jason Rhoads]

I shoot to maintain dkh at around 8, but honestly, for years I didnt know anything about dosing for alk and my tank didnt implode. 

 

It all depends on what SPS you want to keep. Most SPS will probably not die, but they wont grow as quickly either (I assume).  

[jaddc]

I always do 50% water changes and spike the change-out water with cal and mag. After the change my cal is over 450 and the alk is normal. It only takes a couple weeks for the alk to drop close to 5 dkh but then it seems to stay there forever. I can dose with baking soda but raising alk to to 7 makes my softies cringe, especially mushrooms. Can my SPS live with this low alk? If not why is dosing to get higher alk making my softies cringe? Is my water change method related? I've heard dosing to raise alk can make cal drop, true?

 

Why do you add calcium and magnesium to your fresh saltwater?

[jaddc]

In a larger sense -- The values of Mg, Ca and KH don't matter too much (within reason). What matters is that the balance of those levels relative to each other do not change rapidly. So adding baking soda but not calcium chloride will not make your corals happy.

Edited January 29, 2014 by jaddc

[sen5241b]

Why do you add calcium and magnesium to your fresh saltwater?

 

Cause my cal stays high with no need for dosing for about 2 months after the change.

[jaddc]

So when you make fresh salt water, what is your concentration? And what is the measured Ca, Mg and KH values? After you spike in Mg and Ca what are the new values?

[tomtom2245]

I will say that I ran with an alk of around 5dKh for about 2 years with no ill effects seen; corals were all growing and doing good. I did have a few SPS but they grew pretty slow. I have since raised my alk to around 7dKh over a 1-2 week period and have already seen a drastic increase in overall SPS health, no noticeable change in my LPS as of yet. There is no reason IMO to worry about a lower than normal alk level as long as it is stable. Granted you might not see as much growth as quickly but as long as your corals are all happy, I see no reason for concern.

[BowieReefer84]

I think the lowest I would consider ok is 6.0  Anything below that with SPS is flirting with disaster.  6.0-6.5 is in the realm of NSW.

 

You need to understand the correlation of Alk dropping VS Cal dropping.  Every 1pt in alk is like 10ppm in cal (something like that I think).  You MUST balance them and keep them in proper ratios.

 

Also, low alk will keep your PH surpressed.

 

Last of all stability is key.  50% waterchanges with spiked levels would be a bad idea.

 

Read this:

http://reefkeeping.com/issues/2002-04/rhf/feature/

Edited January 29, 2014 by BowieReefer84

[trockafella]

What is your mag at.? I had issues with low Alk and low mag was my reason. Calcium was always fine, but alk would not get above 5.5.  Also, how often are you doing water changes.?

[Origami]

Alk consumption slows drastically at low alkalinity because growth slows drastically. Some SPS species will start to lose tissue when it gets too low.

 

Low alk that does not respond to supplementation is often due to low magnesium. Magnesium allows calcium and alkalinity to exist at high supersaturated levels in salt water.

[zygote2k]

I'd recommend that you not spike your water, but instead to start a controlled dosing regimen. Start weekly testing and then calculate your Alk and Ca consumption. Try dosing enough of A&C to maintain a stable level of each. You may have to use Mg if you have issues with raising either.

Chasing a magic number is just silly because everyone's tank is different and uses A&C at different rates.

[sen5241b]

The Cal in the change out water is 500 PPT. The mag was at the upper limit. The alk was normal. Like I said the magnesium and calcium stays at normal levels for about two months after a 50% change out so except for alk there was no need for dosing. I think I need to raise alk slowly over the course of one or two weeks or do smaller water changes on weekly basis.

I find it very interesting somebody raised their alk slowly over one or two weeks. I had problems when I raised alk over the course of three days.

 

 

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[sen5241b]

UPDATE So I brought up alk very slowly and I'm not worried about whether it's exactly 7 and the tank is looking very good but five was definitely too low.

 

 

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