Alk rising on its own - No dosing

[sanzz18]

Alk rising is unrelated to magnesium at any level.

If you are not adding alk in any way (including top off with tap water), and nitrate is stable and not being dosed, then the alk rise is likely from sand and rock dissolution.

Using a lower alk salt mix for water changes would be a good answer (you can lower alk as low as you want in new salt water), as would means of increasing alk demand in the tank (e.g., corals).

Oh okay. I thought that if your magnesium level is low that it makes the absorption of alkalinity/calcium by corals and other organisms difficult or consume less of it.

What could be some of the sudden causes of decreased alkalinity demand?

I do not believe there are many other salts that mix much lower then red sea bucket. In that case I would have to use an acid to reduce the alk of new saltwater. In order to do a slow decline of alkalinity to get it back to where I wanted it, what would you set the alkalinity of new saltwater yet? (Tank is 180g water volume and goal like I said is around 8/or just under 8dkh).

 

[GarrettT]

Forgive me if already mentioned as I haven’t gone through the entire 3 pages, but do you know what your PH is? When low, Alk is notorious at rising.

 

[Randy Holmes-Farley Verified Community Expert]

Forgive me if already mentioned as I haven’t gone through the entire 3 pages, but do you know what your PH is? When low, Alk is notorious at rising.

It would have to be super low to dissolve calcium carbonate skeletons (below 7.7) , but that principle is why I think sand and rock is dissolving in pores where the pH is even lower.

 

[sanzz18]

Forgive me if already mentioned as I haven’t gone through the entire 3 pages, but do you know what your PH is? When low, Alk is notorious at rising.

Just this past week, never droped below 7.9 and peaks at just 8.2. Previous weeks looks similar.

It would have to be super low to dissolve calcium carbonate skeletons (below 7.7) , but that principle is why I think sand and rock is dissolving in pores where the pH is even lower.

That I guess would literally be the only other than nitrate consumption right? Tonight my alk was up a other .2 dkh (9.6). No I am worried my sps will wipe out as I already have burnt tips from stripping phosphate too fast.

Should I use acid to lower NSW to where I want my alk at or should I go a little lower?

 

[GarrettT]

It would have to be super low to dissolve calcium carbonate skeletons (below 7.7) , but that principle is why I think sand and rock is dissolving in pores where the pH is even lower.

Right around 7.7 (morning low point) is when my Alk starts to rise, however we are only talking about .1 dKh per day, so nothing too crazy. Over a week period, it does start to add up though. The unfortunate part is that I rely on Kalk for some of my Alk, so if I stop dosing, it becomes a catch 22. That said, when I catch it, fanning an open window and co2 scrubber always brings things back to normal.

 

[Randy Holmes-Farley Verified Community Expert]

Usually a little dissolution is just lost in the large demand for alk and calcium. It’s only when demand is very low that one could detect it.

 

[Gatorpa]

The pH down in sand is lower than in the bulk water due to degradation of organics producing CO2.

It is pretty normal and long term reefers often need to replenish sand. The contribution to alk and calcium usually goes unnoticed unless demand is very low, where it becomes noticeable.

Could you be so kind as to elaborate on long term reefers replenishing sand?

At what age of tank do you see this?

My setup currently has sand that’s prob ten years old, it’s not a super deep bed. I don’t have issues with alk dropping but on occasion i will see alk suddenly run up from about 8.5 to 9 in a single day. I dose about 15 mls of seachem two part a day.and about 2 liters of kalkwasser in ATO a day.
When that happens I pause or cut back the dosing and then it drops back down the next day.
It just happened recently.

 

[sanzz18]

Sorry to beat a dead horse. I was just wondering what dkh I should lower my new saltwater to? I am grabbing muriatic acid this weekend.

For aeration should I use an ayirstone or just a powerhead at the surface?

 

[Randy Holmes-Farley Verified Community Expert]

Sorry to beat a dead horse. I was just wondering what dkh I should lower my new saltwater to? I am grabbing muriatic acid this weekend.

For aeration should I use an ayirstone or just a powerhead at the surface?

Either way of aerating will work.

if you reduce alk to 5 dKH in the new salt water, then a 10% water change on a tank with 9.6 dKH will drop it to 9.14 dKH.

 

[sanzz18]

@Randy Holmes-Farley could a GHA outbreak drive alkalinity levels up? Since this last post the alk level was pretty decent. Then I noticed it rising again at the same time GHA was noticed then taking off. Since GHA consumes both phosphate and nitrate, can’t the consumption of nitrate release alk back into the water column?

Also, if the dissolution of sand is part of the problem, how can I fix/manage this until my tank has coral and can actually uptake some of the alk? It is hard to add corals with constantly battling fluctuating alkalinity.

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley could a GHA outbreak drive alkalinity levels up? Since this last post the alk level was pretty decent. Then I noticed it rising again at the same time GHA was noticed then taking off. Since GHA consumes both phosphate and nitrate, can’t the consumption of nitrate release alk back into the water column?

Also, if the dissolution of sand is part of the problem, how can I fix/manage this until my tank has coral and can actually uptake some of the alk? It is hard to add corals with constantly battling fluctuating alkalinity.

Only if it dropped nitrate. A 50 ppm drop in nitrate boosts alk by 2.3 dKH.

Managing sand dissolution is hard, but keeping pH lower and the sand clean of detritus likely helps.

 

[sanzz18]

Only if it dropped nitrate. A 50 ppm drop in nitrate boosts alk by 2.3 dKH.

Managing sand dissolution is hard, but keeping pH lower and the sand clean of detritus likely helps.

The algae was definitely consuming nitrates. I monitored levels most of the battle.

I honestly am just so stumped on how to keep my alkalinity consistent/stable so I can actually keep SPS in my tank and not worry about level fluctuations killing frags.

 

[GarrettT]

Sorry to beat a dead horse. I was just wondering what dkh I should lower my new saltwater to? I am grabbing muriatic acid this weekend.

For aeration should I use an ayirstone or just a powerhead at the surface?

I still think this is directly tied to your PH, but that’s just from my own personal experience. Don’t think this is related to your nitrates. I would absolutely scrub newly added saltwater if you’re adding MA, have a moderate PH, and having Alk inconsistencies

I added a union to the base, as I have another union (same type to be interchangeable), but with a barb/vinyl hose attached to the female end for the water change. Same pump mixing the salt and doing the water change.

 

[Randy Holmes-Farley Verified Community Expert]

The algae was definitely consuming nitrates. I monitored levels most of the battle.

I honestly am just so stumped on how to keep my alkalinity consistent/stable so I can actually keep SPS in my tank and not worry about level fluctuations killing frags.

FWIW, it’s the change in nitrate concentration that impacts alk, not just consumption if the nitrate comes from food

 

[Northern Flicker]

I am to dumb for this hobby.

 

[sanzz18]

I still think this is directly tied to your PH, but that’s just from my own personal experience. Don’t think this is related to your nitrates. I would absolutely scrub newly added saltwater if you’re adding MA, have a moderate PH, and having Alk inconsistencies

I added a union to the base, as I have another union (same type to be interchangeable), but with a barb/vinyl hose attached to the female end for the water change. Same pump mixing the salt and doing the water change.

This is typically where my PH stays. So it hasn’t even been low and I also haven’t been doing water-changes the last few months because the GHA was consuming so much of my nutrients I was afraid of bottoming out. So the MA hasn’t even been used recently.

FWIW, it’s the change in nitrate concentration that impacts alk, not just consumption if the nitrate comes from food

I kind of understand this lol

I am to dumb for this hobby.

Lol I really am too. I had it hahaha

I just freaking want to be able to keep SPS and some LPS in my 2 1/2 year old tank hahaha. I wanted a reef tank not a FOWLR.

 

[GarrettT]

Ph fluctuates throughout the day that’s of no concern. It’s the inconsistent fluctuation from day to day that is and will impact your Alk.

This is what you want

Not this

All that said, I personally think keeping a steady Alk is overhyped. Is it better? sure. Will it devastate your corals if levels fluctuate within reason? No.

 

[fodsod]

I am to dumb for this hobby.

That thought plagues my mind daily.

Good post OP. I've seen a similar event in my tank that eventually resolved itself. I'm very curious to know if you get this figured out.

 

[Mr.Guy83]

I’ve had this battle for close to a year with no real answers. I’ve used the MA method in new saltwater. I’ve replenished sand . I’ve done 20% water changes every two day for two weeks. And like clockwork it slowly creeps back up.

 

[Randy Holmes-Farley Verified Community Expert]

I’ve had this battle for close to a year with no real answers. I’ve used the MA method in new saltwater. I’ve replenished sand . I’ve done 20% water changes every two day for two weeks. And like clockwork it slowly creeps back up.

While there are a variety of reasons alk can rise, the answer can be in the water changes by lowering the alk in them as low as you want.