Aquarium Chemistry Question? Ask the Doctor!

[canadianeh]

No, it will not impact calcium.

it may impact demand for alk and calcium going forward, but an alk addition has no immediate impact on calcium.

There is no "normal" for alk swing. Daily alk demand is usually 0.5 to 3 dKH per day. The swing varies with how often you supplement. I'd try to keep it stable within a 0.5 dKH range.

So I have been using the calculator that you suggested to dose the Alkalinity. Originally I started with 7.46 Alk. According to the calculator I need to dose 15.6ml of Alk to bring it to 8 dkh.

On Aug 31 at 11pm I dosed 7 ml.

Sep 1 at 3 pm - Alk showed 7.63 according to Trident. I then dosed 8 ml more. At 7 pm, Alk showed at 7.91 dkh.

Sep 2 at 9 pm I dosed the remaining 0.6 (total of 15.6 ml).

Sep 3 - after I replaced the Trident Reagent A, Alk showed at 7.84 (it came down?). I used to the calculator again, and dosed 4.6 ml to bring it to 8 dkh.

Now the Alk is showing 7.95 dkh.

Why I didn’t get 8 dkh after I completed the 15.6 ml dosing? Should I continue to use the calculator and dose again until I see 8 dkh?

 

[Brew12]

So I have been using the calculator that you suggested to dose the Alkalinity. Originally I started with 7.46 Alk. According to the calculator I need to dose 15.6ml of Alk to bring it to 8 dkh.

On Aug 31 at 11pm I dosed 7 ml.

Sep 1 at 3 pm - Alk showed 7.63 according to Trident. I then dosed 8 ml more. At 7 pm, Alk showed at 7.91 dkh.

Sep 2 at 9 pm I dosed the remaining 0.6 (total of 15.6 ml).

Sep 3 - after I replaced the Trident Reagent A, Alk showed at 7.84 (it came down?). I used to the calculator again, and dosed 4.6 ml to bring it to 8 dkh.

Now the Alk is showing 7.95 dkh.

Why I didn’t get 8 dkh after I completed the 15.6 ml dosing? Should I continue to use the calculator and dose again until I see 8 dkh?

My guess is it is because you did it over 3 days. You had some alkalinity consumption during that time that likely accounts for the difference. A bulk add would likely have gotten you to the 8dKH. The 4.6ml you added on Sep 3rd is likely your total alkalinity consumption between August 31st and September 3rd.
That is also a very small amount. The other possibility is that it is only an accuracy issue with the concentration of the alkalinity solution and measurement errors for what you added.

 

[Randy Holmes-Farley]

I agree, alkalinity is not stable and any calculation only applies to the instant in time.

I would also never assume one can calculate any of these things exactly as there are many poorly known values, such as the actual volume in your aquarium, the amount of moisture in a dry product you are weighing or the exact bulk density of a dry product you measure by volume, the exact potency of a commercial liquid product, your ability to measure liquid volumes accurately, etc.

Just use calculators as a guide.

 

[Luisreefmexico]

Hello @Randy Holmes-Farley
I am using calcium reactor but i cant set my alkalinity, i am tracking the evolution every 2 days and this are my results.
my tank has a downward trend, i increase the effluent and after two days sometimes the alk is rising but after 2 days again is down.
the ph prove is in 6.5
I am using Reborn media.
should i still rise the effluent of the calcium reactor or reduce the PH in the raction chamber.
Is this normal behavior?
I was introducing small frags, less than 1 inch of acros, could this affect that much?
What is your recommendation?

 

[Futuretotm]

Hello all, I have two questions for the pros:

Salt brand: IO Reef Crystals
Auto water change: 5 gallons per day
Total volume 139 gallons
Tank age - very young - 9 months
Some SPS and LPS

(1) Alkalinity, I use BRS two part, I only dose Alk as my Calcium is usually 500+ (due to IO salt mix?).
I have been dosing 20ml per day, my alk seems to be going down slowly (currently at 8), I have raised it to 30ml/24hr to aim for 9dkh.

Is this (30ml/24hr) normal? or is my sand bed become concrete? I don't see any precipitate elsewhere.


(2)NO3:O4
My NO3 is being taken care of as it hovers under 5ppm, however my PO4 keeps rising, despite LaCL dosing 7ml/24hr and DIY NOPOX 20ml/24hrs it keeps uptrending (0.07 today and on the rise). I do feed with reef roids and I think that may be my culprit here.

But do the bacteria not process PO4 or process less of it than NO3?

 

[Brew12]

Hello all, I have two questions for the pros:

Salt brand: IO Reef Crystals
Auto water change: 5 gallons per day
Total volume 139 gallons
Tank age - very young - 9 months
Some SPS and LPS

(1) Alkalinity, I use BRS two part, I only dose Alk as my Calcium is usually 500+ (due to IO salt mix?).
I have been dosing 20ml per day, my alk seems to be going down slowly (currently at 8), I have raised it to 30ml/24hr to aim for 9dkh.

Is this (30ml/24hr) normal? or is my sand bed become concrete? I don't see any precipitate elsewhere.


(2)NO3O4
My NO3 is being taken care of as it hovers under 5ppm, however my PO4 keeps rising, despite LaCL dosing 7ml/24hr and DIY NOPOX 20ml/24hrs it keeps uptrending (0.07 today and on the rise). I do feed with reef roids and I think that may be my culprit here.

But do the bacteria not process PO4 or process less of it than NO3?

30ml/24 hours doesn't seem bad at all. I was up to over 450ml/day on my 187g system until I set up a CaRx.

Carbon dosing does lower nitrates more effectively than phosphates which is likely why you see your phosphates rising.

 

[drbark]

Question for the chemistry Gods.

Have a 320 gallon total volume system with two tanks connected in this system. One is a fish only tank and the other is a LPS dominant tank. Have a very large sump located behind the DT (150 gallons) that I got from a friend when he took his 500 gallon system down. I have 3 100 micron filter socks, Deltec skimmer, very large chaeto fuge that seems to be working well, running some carbon also.

Was having some phosphate problems with the system and running GFO was inconsistent. Worked well for 2-3 weeks then it spiked
again afterwards. If I ran more GFO, the corals were not as happy so I did not try to get too cute with it.

I have two part dosing system via DOS pumps. Dosing Ca, Mg, and Alk separately.

Don't know exactly what started the problem since it seemed like I changed two things around the same time.
1) Started dosing 15 mls of Phosphat-e from Brightwell Aquatics. Did not use a 10 micron filter but dosed it with a designated DOS pump 15 mls over 24 hrs. Was dosed into a very busy area just before my skimmer and fuge.

2) Changed my salt from RPM to Tropic Marine Pro Reef salt mix at 1.026 SG. Used a auto water change system at 5 gallons per day.

Did not have this specific problem with RPM when I was doing the same auto water change system FWIW.

I soon noticed that my Euphyllias were dying off. Also that my Ca levels shot up from 430 ppm or so to around 580 ppm via Trident. I calibrated my Trident and used two separate Salifert Ca test kits and got the same results. So I stopped dosing Ca to lower it. This is the interesting part. The Ca levels never dropped. Stayed the same. I assumed it's the salt mix. So I switched back to RPM. Waited a month and no Ca drop off. Then I stopped the auto water change system and am doing 10% water changes weekly. Have been doing this for 3 weeks. Ca levels are around 550 ppm via Trident still. Still have not dosed Ca but am dosing Alk as usual. One thing I noticed after stopping the auto water change is that the next day my corals looked better.

So a week later I put a 10 micron filter sock at the end of the phosphat-e dosing line. I have never noticed any precipitation from it but decided to be careful. Now I am only dosing 10 mls per day of phosphat-e. Sorry for the long post but wanted to give you guys enough info to make the best judgment you can.

 

[Futuretotm]

Howdy again @Brew12, @Randy Holmes-Farley I've got another for you.

I dose Randys DIY 5-10mls of NOPOX (Vinegar-Vodka), can I add a little Kalkwasser powder to it to help my pH/alk/ca?

Tank volume 139gal
NO3 5ppm PO4 0.4ppm

 

[Brew12]

Howdy again @Brew12, @Randy Holmes-Farley I've got another for you.

I dose Randys DIY 5-10mls of NOPOX (Vinegar-Vodka), can I add a little Kalkwasser powder to it to help my pH/alk/ca?

Tank volume 139gal
NO3 5ppm PO4 0.4ppm

Not sure what I was thinking.. initially said no. But.. you can use Vinegar to make kalkwasser more fully saturated, so I think it should work.

 

[Randy Holmes-Farley]

Howdy again @Brew12, @Randy Holmes-Farley I've got another for you.

I dose Randys DIY 5-10mls of NOPOX (Vinegar-Vodka), can I add a little Kalkwasser powder to it to help my pH/alk/ca?

Tank volume 139gal
NO3 5ppm PO4 0.4ppm

It will be almost none (very little calcium or alk) because the volume is tiny and there is not much acetic acid in it.

I previously dosed vinegar manually before getting a dosing pump, and I saturated it with calcium hydroxide to prevent the initial pH drop, but that amount of calcium and alk added is tiny.

 

[Randy Holmes-Farley]

We can calculate the amount in 1 g of pure 100% acetic acid.

Acetic acid weighs 60 g/mole, so 1 g is 1/60 mole, or 16.6 millimole.

It will neutralize exactly that amount of hydroxide to dissolve the calcium hydroxide, so the amount of hydroxide/alkalinity dissolved will be 16.6 millimoles.

Your tank is 139 gallons or 526 L.

Thus, you would be adding 16.6 milliequivalents of alk to 526 l or 0.032 meq/l (= less than 0.1 dKH).

 

[Futuretotm]

We can calculate the amount in 1 g of pure 100% acetic acid.

Acetic acid weighs 60 g/mole, so 1 g is 1/60 mole, or 16.6 millimole.

It will neutralize exactly that amount of hydroxide to dissolve the calcium hydroxide, so the amount of hydroxide/alkalinity dissolved will be 16.6 millimoles.

Your tank is 139 gallons or 526 L.

Thus, you would be adding 16.6 milliequivalents of alk to 526 l or 0.032 meq/l (= less than 0.1 dKH).

Thank you for the detailed reply. Any affect on pH? will it even be enough to neutralize the nopox-acids?

 

[Randy Holmes-Farley]

Thank you for the detailed reply. Any affect on pH? will it even be enough to neutralize the nopox-acids?

Sure, just add an excess Ca(OH)2 and use the liquid. It will have a tiny pH boosting effect, at least when first added. Later, as it is mostly converted into CO2, that drop will still be present.

 

[Futuretotm]

Is it worth it?
- 139gallon, pH 8 to 8.1 daily swing
- Wish: chase pH higher with kalkwasser
- Currently: dose Alk (BRS Soda Ash) 30ml only


Any idea if an equivalent dose of kalk can be calculated to my Soda Ash? and if that number will increase my pH...
Complication: I wish to dose kalk via a dosing pump rather than ATO as thats not an option.


So is it worth it....

 

[Randy Holmes-Farley]

Is it worth it?
- 139gallon, pH 8 to 8.1 daily swing
- Wish: chase pH higher with kalkwasser
- Currently: dose Alk (BRS Soda Ash) 30ml only


Any idea if an equivalent dose of kalk can be calculated to my Soda Ash? and if that number will increase my pH...
Complication: I wish to dose kalk via a dosing pump rather than ATO as thats not an option.


So is it worth it....

Sodium carbonate (soda ash) has half the pH raising effect of hydroxide per unit of alkalinity added.

Since you have a dosing pump, you can use sodium hydroxide in the pump in place of sodium carbonate to get the same pH boost as kalkwasser. There are threads on very high pH DIY two parts.

many dosing pumps cannot dose enough kalkwasser daily to be effective.

 

[Futuretotm]

Sodium carbonate (soda ash) has half the pH raising effect of hydroxide per unit of alkalinity added.

Since you have a dosing pump, you can use sodium hydroxide in the pump in place of sodium carbonate to get the same pH boost as kalkwasser. There are threads on very high pH DIY two parts.

many dosing pumps cannot dose enough kalkwasser daily to be effective.

Thank you again.

So essentially dose 15ml of the following solution(283 grams of sodium hydroxide to 1 gallon of fresh water)
instead of the 30ml of BRS soda ash.

 

[Randy Holmes-Farley]

Thank you again.

So essentially dose 15ml of the following solution(283 grams of sodium hydroxide to 1 gallon of fresh water)
instead of the 30ml of BRS soda ash.

For the same pH effect as you get now, but you will get half the alkalinity boost if you cut the dose in half from 30 to 15 mL.

 

[SaltyBish]

.

 

[Futuretotm]

For the same pH effect as you get now, but you will get half the alkalinity boost if you cut the dose in half from 30 to 15 mL.

Just wanted to say thank you. I switched to Lye as you suggested, kept my 30cc daily dose the same, pH now hovers around 8.1 to 8.2+ over 24hours.

 

[Randy Holmes-Farley]

Just wanted to say thank you. I switched to Lye as you suggested, kept my 30cc daily dose the same, pH now hovers around 8.1 to 8.2+ over 24hours.

Sounds good.

Happy reefing!