View Full Version : Alk problem?

07/30/2017, 11:45 AM

My parameters have been stable yet today when I tested the water I found the following;

30 07 17

Salinity 1.0247
Temp 79.5 F
pH 8.2
Alk 6.7 dkh
Ca 465
Mg 1410
Nitrite 0
Nitrate 0-5ppm(API, need to get a better test)
Ammonia 0

My Ca is potentially a little high but the problem I see is the Alk and slightly low SG.

Are these problems likely related? And if not how can I raise the Alk without affecting the Ca and Mg?

The corals (LPS and SPS mix) seems to be doing fine. Nothing dead or receding, though not as much growth as I would of liked.

Been running around 8 months.

Anything Iv missed please ask,

Thanks in advance.

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07/30/2017, 02:38 PM
Baking soda will raise your alk without much effect on calcium or ph.
Do a search to see how much is needed for your tank size.
And do it over the course of few days

07/30/2017, 02:44 PM
Will have a look thank you for the reply

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07/30/2017, 03:13 PM
What corals are in your tank? Unless you have LPS or SPS you need not be too concerned about dKH.

Martin Kuhn
07/30/2017, 03:14 PM
If all of the posted parameters really are like this, I don't see any issue here.
Alk could be a little higher, but just to be more on the safe side. Raising with either baking soda or soda ash has NO influence on Ca (or the other values). Using baking soda drops your ph value, but just a little bit

What is missing AND is of importance for sps growth is your PO4 value.

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07/30/2017, 03:17 PM
Yeah I have a mixed reef style I'm more concerned with the SPS as they are the most recent and I know are more demanding. Iv had moderate success with the LPS already in the tank.

Latest addition.
Green birds nest
Seriatopora hystrix I think?


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07/30/2017, 05:45 PM
I agree that those numbers are generally acceptable. I would keep the dKH at 7 dKH or a bit above, though, to give some leeway in case a test kit is a bit off. Low dKH levels can cause problems for corals. 6.7 dKH is fine if the kit is completely accurate, but that's a dangerous assumption.

I would raise the SG slowly to 1.0264 by topping off with all or part saltwater for a while. There's no rush, and the level as is likely is acceptable. Again, though, I like to have some leeway, and 1.0264 is the canonical ocean average.

Martin Kuhn
07/30/2017, 06:51 PM
@JohnYoung: Again .... caring for sensible SPS a reliable measurement of PO4 (phosphate) is an absolut must.

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07/31/2017, 06:12 AM
Sorry my phone died and I haven't seen the replies.

PO4 is at 0.02 if my tests are to be believed.

Thank you all for the help. I'm aware the SG is slightly low.

So baking soda? How should I dose the calculated quantity? Is it just as simple as mix it with fresh top water?

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07/31/2017, 12:32 PM
Try the calculator


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07/31/2017, 05:12 PM
Is it just as simple as mix it with fresh top water?

mix in ro/di water and add slowly to sump

07/31/2017, 05:13 PM
mix in ro/di water and add slowly to sump

Thank you.

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07/31/2017, 05:28 PM
Raising dkh by up to 1.5 dkh per 24 hour period is your max. BRS has a calculator to account for tank volume and tells you how much to add of various forms of chemicals. Soda ash, baking soda, or etc.

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08/01/2017, 12:45 PM
I keep my sg on the higher side at 1.028