Alkalinity rising without dosing... possible causes?

[sagedrake690]

Aren't mineral acids highly deadly though? I alway been afraid to put HCL in there for fear of how strong it would be. What is the dosage for a 55gal and how do you increase PH without skyrocketing alkalinity?

 

[Randy Holmes-Farley Verified Community Expert]

Aren't mineral acids highly deadly though? I alway been afraid to put HCL in there for fear of how strong it would be. What is the dosage for a 55gal and how do you increase PH without skyrocketing alkalinity?

Lots of pepel use muriatic acid (HCl) to drop alk in new salt water.

The strength of the acid makes no difference to the pH change when it is fully ionized regardless.

For example, adding acetic acid (vinegar, pKa ~5) and HCl (pKa below 0) will both drop pH exactly the same amount per units of alk consumed (and the vinegar gives it all back when it is metabolized).

 

[GlassMunky]

Seems an odd solution that I would not recommend as there are far simpler and cleaner methods. Tannic acid will bind trace metals and impact bioavailability, will potentially yellow the water, and may ultimately be metabolized, releasing some or all of the alkalinity back.

If one really wants to lower alkalinity in a running reef tank without doign water changes with a low alk mix, one way is to do them with a super low alk mix that you make yourself, or by very, very slowly adding a mineral acid to the tank. Sodium bisulfate (like Seachem acid buffer) or hydrochloric acid will permenently lower the alk and do little else besides lower pH when first added (which tannic acid will also lower pH to the same degree per unit of alk depleted).

I’ve used HCL in my mixing container before on rare occasions, but didn’t think it was ok to dose it to the DT full of fish because it would drop pH as well.

What dosage would you recommend starting at for a 220G tank with 65G sump? Maybe start low with a total of 2ml and see how that effects pH?
The tank runs 8.0-8.3 ph every day.

 

[Randy Holmes-Farley Verified Community Expert]

I’ve used HCL in my mixing container before on rare occasions, but didn’t think it was ok to dose it to the DT full of fish because it would drop pH as well.

What dosage would you recommend starting at for a 220G tank with 65G sump? Maybe start low with a total of 2ml and see how that effects pH?
The tank runs 8.0-8.3 ph every day.

Any acid used to drop alkalinity will drop pH by the same amount for a fixed alk drop.

The method does drop pH, and it is not best done in a reef tank. My preferred method is to drop water change water to very low alk (say, 1 dKH), aerate to drive off the excess CO2, then do a water change. But if added very slowly, can work out. Like putting a tiny bit in an ATO.

I wouldn't recommend any amount without know what the alkalinity is and what the goal is.

But adding enough acid to drop the alkalinity by 1.4 dKH dropped pH in new Instant Ocean salt mix from pH 8.1 to 6.91 in my testing. Thus, I think that if alk is high, that if one added enough acid to drop the tank alk by 0.02 dKH at a time, there is little to no concern about pH (as long as it is not added near an organism, but can mix in well before encountering organisms).

I showed that here:

Chemistry And The Aquarium: The Relationship Between Alkalinity And pH

Randy answers many questions in this complex relationship.

reefs.com

 

[Simbol]

Hello All from the UK,

I am experiencing this issue and I suspect my Sand since I am using Marco Rock.. In my case I am using Aquamedic Bali Sand which is apparently made of 98% calcium carbonate.

I am at lost with this because my tank is 700Liters and the amount of water changes I have been doing is not only exhausting.. but very expensive! I am now using HCI to control it.. but this is not a long term solution.. I am new to the hobby the tank has been running for less than 8 months and I feel like I want to give up.. so any help would be appreciated.

This is the only forum where I have found so many people with the same issue as I have.. so at least I know now I am not losing my mind.

If I were to replace my sand, what is the best sand to use in order to avoid this problem? Aragonite is clearly an issue.. mine is also problematic, so what is the alternative?

What is the best way to change the sand? 1/3 per week?

Thanks in advance,
Raul from UK

 

[sgrosenb]

Hi @Simbol sorry for your tank woes. But my advice would be - don't give up! Using acid to lower the alk via something like Seachem Acid Buffer will work, but for me, removing the sand did the trick. I personally really like the look of sand, but I found that it's easier to just remove. I have since bought some LPS to fill some of the bottom of the tank, and I think my goal will be to just fill the bottom with all LPS. It also makes water changes wayyyy easier - no need to sift sand you just take the water out and replace. Overall, I'm a lot happier with no sand.

In terms of taking it out, I do believe it's a destabilizing event. Given that your tank is 8 months old, I'd take it slow. Maybe 1/4 per week and finish in a month, with a water change after each sand removal. Others might have another opinion, but I did it at about that speed and it was fine.

Good luck!!! Let us know how it goes

 

[Randy Holmes-Farley Verified Community Expert]

Hello All from the UK,

I am experiencing this issue and I suspect my Sand since I am using Marco Rock.. In my case I am using Aquamedic Bali Sand which is apparently made of 98% calcium carbonate.

I am at lost with this because my tank is 700Liters and the amount of water changes I have been doing is not only exhausting.. but very expensive! I am now using HCI to control it.. but this is not a long term solution.. I am new to the hobby the tank has been running for less than 8 months and I feel like I want to give up.. so any help would be appreciated.

This is the only forum where I have found so many people with the same issue as I have.. so at least I know now I am not losing my mind.

If I were to replace my sand, what is the best sand to use in order to avoid this problem? Aragonite is clearly an issue.. mine is also problematic, so what is the alternative?

What is the best way to change the sand? 1/3 per week?

Thanks in advance,
Raul from UK

An easier solution than replacing the sand may be to add more organisms that consume calcium carbonate.

But if you want to replace the sand, then a natural silica sand (like beach sand) would be a good plan.

Also, make sure you are not using tap water for top off as it can add a lot of alkalinity.

 

[Jimbo662]

I'm using Tropic Eden reef flakes. Tank is 1 1/2 yrs old. My alk has always avg'd about 8.6. Around the 21st I noticed it slowly starting to increase. after the 2nd or 3rd day I turned off my doser. It's continued to increase and is now at 9.2. The last two days that's the avg. I've not been dosing cal for several weeks and it too has been slowly increasing. Tank is all LPS. Randy have mentioned that in the sand the ph can be lower which could be causing this. Does anyone think it would help if I stirred the sand on a regular basis? I don't do many water changes and don't mess with the sand very much. I was actually looking at placing an order for some cleanup crew that would include some snails that would help stir it up.

 

[schaNYC]

I'm using Tropic Eden reef flakes. Tank is 1 1/2 yrs old. My alk has always avg'd about 8.6. Around the 21st I noticed it slowly starting to increase. after the 2nd or 3rd day I turned off my doser. It's continued to increase and is now at 9.2. The last two days that's the avg. I've not been dosing cal for several weeks and it too has been slowly increasing. Tank is all LPS. Randy have mentioned that in the sand the ph can be lower which could be causing this. Does anyone think it would help if I stirred the sand on a regular basis? I don't do many water changes and don't mess with the sand very much. I was actually looking at placing an order for some cleanup crew that would include some snails that would help stir it up.

I was facing similar issue. Could not figure out so went bare bottom. I was also using tropic eden (mesoflakes).

 

[Randy Holmes-Farley Verified Community Expert]

I'm using Tropic Eden reef flakes. Tank is 1 1/2 yrs old. My alk has always avg'd about 8.6. Around the 21st I noticed it slowly starting to increase. after the 2nd or 3rd day I turned off my doser. It's continued to increase and is now at 9.2. The last two days that's the avg. I've not been dosing cal for several weeks and it too has been slowly increasing. Tank is all LPS. Randy have mentioned that in the sand the ph can be lower which could be causing this. Does anyone think it would help if I stirred the sand on a regular basis? I don't do many water changes and don't mess with the sand very much. I was actually looking at placing an order for some cleanup crew that would include some snails that would help stir it up.

Are you tracking nitrate? Dropping nitrate will also boost alk.

Stirring the sand might help, but is a pain and risks other issues like releasing hydrogen sulfide, if any is present.

 

[Jimbo662]

Are you tracking nitrate? Dropping nitrate will also boost alk.

Stirring the sand might help, but is a pain and risks other issues like releasing hydrogen sulfide, if any is present.

Yes, nitrate is consistently around 25 using a Nyos test kit.

 

[bezj]

Hi. I’m running the Donavans Nitrate Destroyer (see Poor Man's Nutrients Control - Donovan's Nitrate Destroyer).

notwithstanding him being a genius my version is full of ceramic rings/balls. Nitrates have dropped and having stopped dosing alkalinity its still increasing. Currently 11.6

Have sand in tank and sump so plan to remove sump first and complete a few water changes - use Pro Reef Salt which is normally 7.

Any other thoughts?

 

[Randy Holmes-Farley Verified Community Expert]

Hi. I’m running the Donavans Nitrate Destroyer (see Poor Man's Nutrients Control - Donovan's Nitrate Destroyer).

notwithstanding him being a genius my version is full of ceramic rings/balls. Nitrates have dropped and having stopped dosing alkalinity its still increasing. Currently 11.6

Have sand in tank and sump so plan to remove sump first and complete a few water changes - use Pro Reef Salt which is normally 7.

Any other thoughts?

Can you give more info on the alk movements over time?

11.6 dKH is not a big deal, as long as nitrate and phosphate are adequately high to support faster tissue growth by hard corals.

A nitrate decline of 50 ppm boosts alk by 2.3 dKH, and that may how yours rose.

 

[bezj]

Hi. Stopped dosing on 30th Sept. Dkh 10.4 and nitrate was 20ppm (both Hanna checkers). Has increased over the last 3 weeks to 11.6. Nitrate bottomed out to 0 but now at 3.4ppm.

 

[Randy Holmes-Farley Verified Community Expert]

I'd just keep watching it since the nitrate might haver been the cause and cannot add more alk unless you begin to dose nitrate.

If it keeps rising, the water changes with a lower alk mix (you can make them as low as you want) may be an easier solution than removing sand and such.

 

[Jimbo662]

Yes, nitrate is consistently around 25 using a Nyos test kit.

Since my post on the 28th my alk has slowly dropped and is now averaging about 8.6. Still not dosing and no water changes. The only change I've made is putting my filter roller back in the sump and every couple of days I'll stir a small section of sand.

 

[bezj]

Thanks. Makes sense. Didn’t realise a nitrate drop would create such a significant alk increase.

 

[DavidinGA]

Deleted.

 

[fushi]

@Randy Holmes-Farley,

It seems like I have the same issue in my tank that I just restarted. My alk increases slightly less than what you mentioned above “A nitrate decline of 50 ppm boosts alk by 2.3 dKH”. So I imagine I have some but not enough alk consumption.

Being a newer tank with new Carib sea aragonite (the dry non “live” version) I have the common issue of not being able to keep phosphates detectable. I have accidentally let the phosphates drop below zero twice now which spurred Dino outbreaks and RTN of some of the frags. I have been able to beat down the Dinos by elevating nitrate and phosphates and dosing high amounts of silicates. However I now find the problem of my alk increasing as my N & P are used up.

The tank is sucking up a ton of phosphates, I have Trisodium phosphate on a doser at 0.12ppm/day and still have to dose up around 0.06ppm extra after testing in the mornings to get it back to 0.1ppm.
I dose Sodium Nitrate maybe around 1-2ppm everyday/every other day to keep it around 10ppm but haven’t been paying as much attention to the amount I dose.
( ~10ppm N and 0.1ppm P or higher seems to keep the dinos away)

Do you have a recommendation on how to keep my Nitrate and Phosphate elevated without increasing alk?



I have a bunch of sps frags in the tank and they are encrusting but clearly not fast enough.

I only dosed the silicates for a short period to help diatoms outcompete the dinos however I remember reading that high silicates can cause slow coral growth; so I guess that isn’t helping either.

I recently purchased Tropic Marin Phos-Feed to try instead of using the TSP I am currently using but after reading this thread I don't think it will change anything. Also what do you think “phosphate mineral powder” is, its active ingredient.

I just order seachem acid buffer to add to my top off water.

 

[Randy Holmes-Farley Verified Community Expert]

Some of the diy ammonia dosing recipes are neutral or alk lowering (1 of each type), and the diy phosphate dosing is a very small effect but can be alk lowering, neutral, or alk raising.