Questions on managing Alkalinity.

[SaltyinNJ]

Hi,
I have mostly kept FOWLR or softy and easy LPS tanks in the past using primarily water changes for managing chemistry. But I have started a 50 gal SPS dominant tank over the past year and a half with mostly smaller frags now.
I am currently using Reef Crystals for salt mix and my alkalinity runs 10-11 dKH, calcium 450 ppm, mag 1300 after weekly 10% water changes.
I am starting to see my alkalinity demand starting to increase and my alk will drop to 9.0-9.5 by the end of the week before my water changes.
My question is am I okay keeping my alkalinity in the 10-11 range or should I try to target 8-9 which I keep reading is more ideal for SPS?
I anticipate that I will need to begin dosing soon and am planning on using All For Reef or BRS 2 part.
Thanks.

 

[Jsteidl]

The key with Alk is to keep a stable number, whatever that be. Personally I keep my tank at about 9 using a calcium reactor. You can go with a reactor or dose with supplements. In the long run, the reactor will be your best for the money.

 

[BryanM]

There's good info and a calculator in this thread for dosing sodium carbonate.

Ranges for alk very depending on who / where you read. I see nothing wrong with 10-11 if everything seems healthy.

 

[LobsterOfJustice]

Personally, I like to see alk below 9 dkh. Some people have success with higher alk, but you need to be more careful about lighting and nutrient levels when you run an elevated alkalinity. I use sodium bisulfate to lower the alkalinity of newly mixed SW prior to a water change.

 

[SaltyinNJ]

Personally, I like to see alk below 9 dkh. Some people have success with higher alk, but you need to be more careful about lighting and nutrient levels when you run an elevated alkalinity. I use sodium bisulfate to lower the alkalinity of newly mixed SW prior to a water change.

I have read about higher alk requires stricter nutrient control. So if interested in lowering alk do you recommend lowering it with sodium bisulfate or should I consider trying to change to a salt with lower alk?

 

[X-37B]

Just let the alk go down on its own to your desired level. Then start dosing.
Don't add bisulfate to a populated system.
You can use it to adjust your salt prior to a wc.
I use blue bucket with an alk of 8.
My systems run 7-7.5. So no need to adjust incoming wc water to lower alk.

 

[Randy Holmes-Farley]

I'm a bit confused on what you are reporting, but the current alk is fine and I'm not seeing a reason to try to raise it.

 

[SaltyinNJ]

I'm a bit confused on what you are reporting, but the current alk is fine and I'm not seeing a reason to try to raise it.

I am not trying to raise my alk. Trying to determine if there is benefit to trying to reduce my alk down into the 8-9 range as opposed to 10-11.
Someone suggested lowering mixed saltwater down into my desired range with sodium bisulfate which I am not familiar with. Thanks.

 

[Randy Holmes-Farley]

I am not trying to raise my alk. Trying to determine if there is benefit to trying to reduce my alk down into the 8-9 range as opposed to 10-11.
Someone suggested lowering mixed saltwater down into my desired range with sodium bisulfate which I am not familiar with. Thanks.

Well, you said it was 9.0-9.5 by the end of the week. Hence my suggestion that it is fine.

If you want to lower it, that's fine too and bisulfate is a fine way.

I do not think you are likely to see an improvement (or detriment) in anything by letting alk fall another half dKH.

 

[SaltyinNJ]

Just let the alk go down on its own to your desired level. Then start dosing.
Don't add bisulfate to a populated system.
You can use it to adjust your salt prior to a wc.
I use blue bucket with an alk of 8.
My systems run 7-7.5. So no need to adjust incoming wc water to lower alk.

Yes I understand not to make changes in the system itself. Thanks.

 

[SaltyinNJ]

I am not trying to raise my alk. Trying to determine if there is benefit to trying to reduce my alk down into the 8-9 range as opposed to 10-11.
Someone suggested lowering mixed saltwater down into my desired range with sodium bisulfate which I am not familiar with. Thanks.

Well, you said it was 9.0-9.5 by the end of the week. Hence my suggestion that it is fine.

Oh I understand. But when I do my weekly water change it bumps me back up to 10+. So if I want to stay in that lower 9ish range should I switch to a salt with a lower dKH or not worry and let it just drift down on its own?
I guess I am asking how would I keep it lower if I wanted to.

 

[exnisstech]

I've never had any interest in having to make adjustments to my fresh saltwater before I can use it. I keep my SPS tank 8 -9 dkH using AFR. I like 8ish dkH because it leaves some wiggle room up or down if needed. I use IO purple which mixes just over 9 dkH when tested. That is close enough that I do WCs with no adjustments needed.

 

[SaltyinNJ]

I've never had any interest in having to make adjustments to my fresh saltwater before I can use it. I keep my SPS tank 8 -9 dkH using AFR. I like 8ish dkH because it leaves some wiggle room up or down if needed. I use IO purple which mixes just over 9 dkH when tested. That is close enough that I do WCs with no adjustments needed.

Okay that makes sense. I have used Instant Ocean for my old tank but never paid attention to its alkalinity back then to be honest. I will consider this.
Thanks

 

[Randy Holmes-Farley]

Oh I understand. But when I do my weekly water change it bumps me back up to 10+. So if I want to stay in that lower 9ish range should I switch to a salt with a lower dKH or not worry and let it just drift down on its own?
I guess I am asking how would I keep it lower if I wanted to.

What size water changes do you do? I use normal IO for daily small water changes, and my alk is well below the salt mix level.

But if you want to keep doing largeer water changes, then using a lower alk mix, or lowering your preferred salt mix is a fine plan.

 

[Kooma]

Sounds like your water changes are managing it for now. I personally dose AFR and have limited my water changes to every 2-3 months. A dose and AFR helps keep it stable, but if things are happy and you are good with your effort you can keep doing what you are already doing. I ran a mixed reef with successful sps for many years with nothing but purple bucket IO water changes every Saturday.

 

[SaltyinNJ]

Oh I understand. But when I do my weekly water change it bumps me back up to 10+. So if I want to stay in that lower 9ish range should I switch to a salt with a lower dKH or not worry and let it just drift down on its own?
I guess I am asking how would I keep it lower if I wanted to.

What size water changes do you do? I use normal IO for daily small water changes, and my alk is well below the salt mix level.

But if you want to keep doing largeer water changes, then using a lower alk mix, or lowering your preferred salt mix is a fine plan.

Thanks. Usually 20-% every other week. Maybe doing less more frequently would be better then.

 

[SaltyinNJ]

Sounds like your water changes are managing it for now. I personally dose AFR and have limited my water changes to every 2-3 months. A dose and AFR helps keep it stable, but if things are happy and you are good with your effort you can keep doing what you are already doing. I ran a mixed reef with successful sps for many years with nothing but purple bucket IO water changes every Saturday.

Thanks, yes I don’t have a large demand yet. I get that the water changes can throw off things. Makes sense.