Lowering Alk using sodium bisulfate

[Mr.Guy83]

Hello Randy I’ve read your thread from many years ago about lowering the alk in newly mixed water change water using sodium bisulfate in efforts to lower tank alk. But being completely honest my brain doesn’t remotely think the way yours does so I was hoping you could dumb it down for me.

currently my tank Alk is 10.9 the salt I use is tropic Marin pro reef salt. My end goal is to get my reef system alk to around 8.5. Here are the questions I have

1. how quickly can I complete this safely. ( how many five gallon water changes)
2. How much sodium bisulfate do I add to the five gallon buckets?
3. Do you still recommend the sodium bisulfate brand from your 2018 post or is there a newer/better product you recommend?
4. When you say aerate the water to brithe ph back up, can that be done with power heads or would I need to purchase and air stone?
5.does it matter if I add the bisulfate before or after the salt?

thanks I’m advance and please let me know if there is anything important I overlooked. Have a great night.

 

[Mr.Guy83]

Hello Randy I’ve read your thread from many years ago about lowering the alk in newly mixed water change water using sodium bisulfate in efforts to lower tank alk. But being completely honest my brain doesn’t remotely think the way yours does so I was hoping you could dumb it down for me.

currently my tank Alk is 10.9 the salt I use is tropic Marin pro reef salt. My end goal is to get my reef system alk to around 8.5. Here are the questions I have

1. how quickly can I complete this safely. ( how many five gallon water changes)
2. How much sodium bisulfate do I add to the five gallon buckets?
3. Do you still recommend the sodium bisulfate brand from your 2018 post or is there a newer/better product you recommend?
4. When you say aerate the water to brithe ph back up, can that be done with power heads or would I need to purchase and air stone?
5.does it matter if I add the bisulfate before or after the salt?

thanks I’m advance and please let me know if there is anything important I overlooked. Have a great night.

@Randy Holmes-Farley

 

[Miami Reef]

I searched “Tropic Marin Pro Reef Salt” and saw the mixed alkalinity is around 7dKH.

I think the solution here is to lower the amount of alkalinity dosed and allow it to naturally come down.

 

[Spare time]

Just let it drop on its own. An alk at that level isn't really problematic unless you run an ULNS (which is unpopular these days). No need to stress over it.

 

[Miami Reef]

Just let it drop on its own. An alk at that level isn't really problematic unless you run an ULNS (which is unpopular these days). No need to stress over it.

Exactly. I started keeping a higher alkalinity myself.

 

[Mr.Guy83]

I searched “Tropic Marin Pro Reef Salt” and saw the mixed alkalinity is around 7dKH.

I think the solution here is to lower the amount of alkalinity dosed and allow it to naturally come down.

Well, that’s one thing that confuses me. I do a 5 gallon water change weekly and my alk does not drop. Are the water changes too small to make a significant drop? My total water volume is 34 gallons

 

[Reef.]

Just use the new salt, the alk will drop nice and slow, no need to waste a lot of salt and water changing the water.

But yes if using that product (I use Seachem acid buffer which is the same I believe) you can just use a power head but it takes around 24 hours to get the ph up, if you use an air stone it takes an hour or 2.

 

[Mr.Guy83]

I searched “Tropic Marin Pro Reef Salt” and saw the mixed alkalinity is around 7dKH.

I think the solution here is to lower the amount of alkalinity dosed and allow it to naturally come down.

Also, I don’t dose anything havent dosed in close to a year. So I’m unsure how it got that high begin with. Only thing I’ve added is brs mag.

 

[Reef.]

Well, that’s one thing that confuses me. I do a 5 gallon water change weekly and my alk does not drop. Are the water changes too small to make a significant drop? My total water volume is 34 gallons

It will be dropping but depending on your testing method, you might not see a drop with just one change.

 

[Mr.Guy83]

It will be dropping but depending on your testing method, you might not see a drop with just one change.

It’s definitely been this high for a min. of 6 months of weekly water changes. I only have about 8 sps frags in the system so I guess the consumption is extremely low

 

[Reef.]

It’s definitely been this high for a min. of 6 months of weekly water changes. I only have about 8 sps frags in the system so I guess the consumption is extremely low

But if the tank is 11 and you are using 7dkh water, then the alk will drop even if the tank uses no alk.

You are either testing wrong or your salinity it wrong.

Are you using plain rodi water to topup, not salt water?

 

[Reef.]

Changing 5 gallons a week, would mean you have replaced all the water in 7 weeks, yet you say you have been using the lower alk salt for 6 months!

Sounds like you are testing your alk incorrectly or salinity, or not using plain rodi water to top up.

 

[attiland]

Also, I don’t dose anything havent dosed in close to a year. So I’m unsure how it got that high begin with. Only thing I’ve added is brs mag.

Not sure how much mg you have dosed but higher mg results higher and more stable alk in my tank.

 

[Mr.Guy83]

But if the tank is 11 and you are using 7dkh water, then the alk will drop even if the tank uses no alk.

You are either testing wrong or your salinity it wrong.

Are you using plain rodi water to topup, not salt water?

Yes , plain rodi water. I know it sounds weird and I’ve made several posts about it before. Everyone says what’s happening is impossible but it’s definitely happening and I can’t figure out why

 

[Mr.Guy83]

Not sure how much mg you have dosed but higher mg results higher and more stable alk in my tank.

My mag sits around 1400

 

[Acros]

Can you get the LFS or someone else to test it? That will help rule out a test kit error.

 

[Acros]

A word of caution, sodium bisulfate will reduce oxygen/ph of your water. Hence not recommend as an in tank treatment.

Do you use crushed coral as substrate?

 

[Reef.]

A word of caution, sodium bisulfate will reduce oxygen/ph of your water. Hence not recommend as an in tank treatment.

Do you use crushed coral as substrate?

Yes, this is a point I was meaning to make as it wasn’t clear from the posts if the op was meaning to lower his new salt mix or try and lower the Intank water?

Don’t try and lower the display alk with live animals in the display.

 

[Miami Reef]

A word of caution, sodium bisulfate will reduce oxygen/ph of your water. Hence not recommend as an in tank treatment.

Do you use crushed coral as substrate?

Sodium bisulfate will not reduce oxygen. It will lower pH and increase CO2.

We do not recommend adding sodium bisulfate directly to the tank to lower alkalinity. It can be done, but VERY slowly.

It’s much safer to do it outside the tank because you can bring back up the pH by aerating heavily for 24 hour before doing the change.

But I digress, if you don’t find the cause of your alkalinity rising, it will most likely revert back to your current level.

 

[Reef.]

Yes , plain rodi water. I know it sounds weird and I’ve made several posts about it before. Everyone says what’s happening is impossible but it’s definitely happening and I can’t figure out why

What alk test kit do you use? Have you tried a difference one or a new reagent.

If you have a pair of 0.01g scales ($20 Amazon) you can very easily make a alk reference solution, you then test that to see if your testing kit is reading correctly.

Yes it sounds very weird and I would not believe that is happening until you rule everything else out first, a slight increase may be possible on paper but for over 6 months, with you using 4dkh lower water when doing water changing, I would discount a natural increase.