Alkalinity on a downward path...

[SereneAquatic]

I currently have a tank that is only about 2 months old.

A bonded pair of Clownfish in the display, nothing else, and chaeto and the Kessil H380 in the sump.

I have dosed a small amount of pH buffer twice, hoping it would also help stabilize and maybe raise the alkalinity, but the pH itself isn't terrible. It hangs around 8.03, and could stand to come up a little, but doesn't move much so I haven't been too worried.

The problem is that the alkalinity never stops dropping. It has been on a downhill path since I started testing it. The very first test, that I must have done wrong, was 13 dkh, but the next was 8.12. In the last month, it has reached almost 6.0, despite the buffering.

Do I need to add baking soda? What is making it drop without anything really in the tank yet?



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[Drix]

So, I'm just getting back into the hobby, so take my statement with a grain of salt, but if I remember correctly: if you're experiencing an alk or PH drop, as far as I know somewhere you're either running into a bad CO2 exchange where CO2 is building up, or you're acquiring acidic waste products (poop).

If I had to guess, your tank is more or less still cycling as the beneficial bacteria sort of flex themselves out. I'm not sure I'd bother running after the small time PH changes, but I would keep dosing buffer until things stabilized.

 

[Tom39]

If you are not keeping coral in your tank I would not be concerned with a low alk level. However, if you are looking to keep coral in the future and want to keep up with alk, I would start dosing 2-part (http://reef.diesyst.com/chemcalc/chem_calc3.html)

In reality, without personally observing and monitoring your tank, I or anyone else would be guessing as to the reason for the depletion of alk.
However, a question comes to mind because of past experiences. What is the level of alk in the water you are using for water changes? I ask because, one salt I used before claimed to get 13dkh but when mixed it only tested 7dkh. So is it possible that you are not raising your level of alk like you think you are with a water change but in fact decreasing it with every water change?

HIH
Tom

 

[SereneAquatic]

If you are not keeping coral in your tank I would not be concerned with a low alk level. However, if you are looking to keep coral in the future and want to keep up with alk, I would start dosing 2-part (http://reef.diesyst.com/chemcalc/chem_calc3.html)

In reality, without personally observing and monitoring your tank, I or anyone else would be guessing as to the reason for the depletion of alk.
However, a question comes to mind because of past experiences. What is the level of alk in the water you are using for water changes? I ask because, one salt I used before claimed to get 13dkh but when mixed it only tested 7dkh. So is it possible that you are not raising your level of alk like you think you are with a water change but in fact decreasing it with every water change?

HIH
Tom

I'm using Instant Ocean, the base kind. I may check it, just to see.

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[Uncle99]

What is your magnisum level......should be Say 1320 to 1360....
Magnisum is the buffer to Alk and calcium....get mag right on....then small water change...test for Alk and cal....then dose upwards only if needed....

 

[Uncle99]

BTW...I have heard others saying instant ocean mag test low at 1120......
I use vibrant sea which is test on point for everything and is competitively priced...

 

[mcgyvr]

Do you have a lot of coralline algae in the tank?
Have you tested mag levels too?
What is your current water change schedule? how much..how often

I'd be very suspicious of showing substantial alk consumption in a tank with no corals and little to no coralline algae..

Stop adding ph buffer if you haven't already.
Test mag levels (if you have that test kit)
Then check alk again both in a newly mixed batch of salt water then in the tank about an hour after the water change.. write those down.
Then check alk again the next day.. write it down..
Then check it a day or 2 after that. write it down..

report back..

See if you see a proper downward trend and find out your daily consumption rate..

Without corals water changes alone should be sufficient to keep levels fairly stable..

 

[Uncle99]

Excellent advice above, I would follow it exactly as stated...

 

[SereneAquatic]

Do you have a lot of coralline algae in the tank?
Have you tested mag levels too?
What is your current water change schedule? how much..how often

I'd be very suspicious of showing substantial alk consumption in a tank with no corals and little to no coralline algae..

Stop adding ph buffer if you haven't already.
Test mag levels (if you have that test kit)
Then check alk again both in a newly mixed batch of salt water then in the tank about an hour after the water change.. write those down.
Then check alk again the next day.. write it down..
Then check it a day or 2 after that. write it down..

report back..

See if you see a proper downward trend and find out your daily consumption rate..

Without corals water changes alone should be sufficient to keep levels fairly stable..

There are no corals and no coralline algae. There is a tiny amount of hair algae that seems to be receding, and some cyano that had appeared recently but receded when I put a powerhead in the tank. (A small bit still hangs out where the flow isn't as good).

The sump has a ball of chaeto and Kessil H380, no additional filtration at this time.

I admit that I haven't done a lot of water changes yet... Other than the alkalinity dropping, the tank hasn't seemed to really need it.

The weird thing is that after I did the most recent pH buffer dose... The pH actually went DOWN.

Not quite sure what is going on. The only other change I made was reducing the amount on chaeto since it was getting pretty thick, so maybe that impacted it.

I will do as you suggest and check back in.

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[sde1500]

PH Buffer is a total waste of time, since PH adjusts based mostly on external factors. I'd echo what the others have said, also to double check the test kit you are using. Might be expired or you may not be using it correctly, with such large swings. Though if Alk is not stable in a tank with little in it, mg would be my guess.

 

[SereneAquatic]

PH Buffer is a total waste of time, since PH adjusts based mostly on external factors. I'd echo what the others have said, also to double check the test kit you are using. Might be expired or you may not be using it correctly, with such large swings. Though if Alk is not stable in a tank with little in it, mg would be my guess.

The pH readings are coming from the Apex probe. It doesn't ever leave the water, mounted in a bracket, so if it's the probe, it isn't consistently out of whack. It makes more sense that the pH is fluctuating, but maybe not.

Alkalinity is tested with the Hannah Checker. Every reading is a few digits lower.

Someone earlier in this thread mentioned the tank may still be cycling to some extent... How does that play a role in dkh? Can anyone explain?

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[sde1500]

Someone earlier in this thread mentioned the tank may still be cycling to some extent... How does that play a role in dkh? Can anyone explain?

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It doesn't.

 

[Sk8r]

Never mind ph as a primary indicator in a marine tank, unless you have a special situation. Alk is the best to track, along with Magnesium. Keep mg around 1350 and your alk will stay up. If mg is below 1200 you can buffer til your pipes are clogged and you won't raise or stabilize the alk.

 

[SereneAquatic]

Do you have a lot of coralline algae in the tank?
Have you tested mag levels too?
What is your current water change schedule? how much..how often

I'd be very suspicious of showing substantial alk consumption in a tank with no corals and little to no coralline algae..

Stop adding ph buffer if you haven't already.
Test mag levels (if you have that test kit)
Then check alk again both in a newly mixed batch of salt water then in the tank about an hour after the water change.. write those down.
Then check alk again the next day.. write it down..
Then check it a day or 2 after that. write it down..

report back..

See if you see a proper downward trend and find out your daily consumption rate..

Without corals water changes alone should be sufficient to keep levels fairly stable..

Today I finally got time to test Mg in the tank. These numbers are BEFORE the large water change we are about to do.

Currently the Mg is reading at 1000ppm.
Dkh according to Hannah checker is 6.16.
Dkh according to RedSea Pro is 5.6.

I will post back after the water change, but I'm also going to try to upload the pic of all dkh readings I have done since the tank was set up. You can see it clearly on a down path. I didn't put dates because it wasn't meant to be a log, just a cheat sheet for translating the numbers. The cheat sheet numbers just never read the same, it's always less.

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[Sk8r]

Start by dosing mg recommended amounts daily until you reach 1350. Then start working on the dkh alk, until it stands at 8.3. Then check your calcium, and dose that to 420. Overshooting all these a little is ok, btw.
If you want to stabilize these, stir 2 tsp kalk powder into each gallon of topoff freshwater, and you will hold them rock steady at the good reading until, very, very slowly, the mg falls below 1200.

 

[billdogg]

^^^Exactly what Sk8r said^^^

With your Magnesium at 1000, it's almost impossible to get your Alkalinity up to where it should be.

Using the BRS calculator ( https://www.bulkreefsupply.com/reef-calculator ) and guessing your total volume to be ~80g, you need to add 2258ml of the BRS Mg solution. If using the BRS Mg, you can safely add about 700ml/day x 3 days to raise it about 100ppm/day.

Only then will your Alkalinity start to show improvement.

hth!

Also - FWIW - I have not tested pH for well over 25 years. It is a meaningless number that too many chase and end up adding crap that they just don't need to their tanks in a futile attempt to hit a arbitrary number that can swing wildly depending on time of day, time of year, number of people in the area (increased CO2) etc.

 

[SereneAquatic]

Thank you for the feedback. I will look into perhaps dosing, but I may do some testing on the salt water I am adding, etc. I wouldn't think that two clown fish would be using up the Mg that quickly. I would like to get an idea of how fast it is being used up.

I would like to keep the tank in a ready - for - coral state so that when we find that right one we can be confident adding it. We are going to Reefapalooza Orlando in April. If i manage not to buy anything it will be a miracle hehe

If I find anything else strange I will check back in. Thank you all for the guidance!

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[billdogg]

IME, Mg is used very slowly. I only test for it if my Calcium or Alkalinity starts to go out of whack. Maybe every couple months, and I have a 120DT pretty well full of SPS with a few LPS added in. I use BRS dosing pumps for daily additions of CA and Alk - Mg I just pour in the sump if needed.

 

[allendehl]

As mcgyvr said before, you need a baseline. I use IO and my Mag does not drop that bad. I change water every 2 weeks. Test your freshly mixed water, I'd also test the tank a few hours after wc to account for the parameters balancing out with the remaining water. Then every couple of days to establish a pattern.
The guys that have commented above are absolute masters in the hobbie but I wouldn't start dosing until you find out what is going on in your tank. It is not normal.


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