Why was an Alkalinity of 8 too high?

[ocncheffy]

So I've been fighting with some burnt tips/STN on my SPS with the following parameters:

Alk - 8.1
Calcium - 450
Phosphate - .1
Nitrate - 10
Mag - 1400

I understand that low nutrients of near 0 can cause burnt tips/STN in SPS, but I would have never thought that the levels posted above were considered low nutrients. Since dropping my alkalinity to NSW 7.0, most SPS have healed up nicely. My lighting is set up for around 200 PAR at the top of the rockwork, with dual XR15 G4 pro's and Reefbrite strips. This took me months to figure out, and an ICP test, but nothing conclusive came back. Has anyone else experienced similar issues with requiring Alkalinity at around 7.0?

Note - Testing of alk was done with Hannah, NYOS, and Aquaforest for triple confirmation


*Edit backstory:


Some backstory:

A year ago I let my phosphates rise to .4ppm and ran alkalinity of around 8-8.5 at the time. I then decided to slowly drop my phosphates down to .1-.15 in hopes of increasing growth. Issues started a few months after this change in mid 2021. However, at .4 my tank looked amazing and SPS were taking off quickly. Could it simply be that my tank doesn't like having such low Orthophoshates (Hannah ULR Testing) and the balance was better when it was at .4? I know Mark from SaltwaterAquarium runs his phosphates at .5ppm and has crazy growth.

I don't know if I should go down the road again of simply letting my phosphates do what they want, yet that is also when my tank looked it's best... Thoughts?

 

[Doctorgori]

I’m assuming you know you can’t run your alk long term at 7…
what test kit are you using and how old are the reagents ?
either way I’d confirm my alk reading and slowly raise it to NSW if you got the nerve, …. IME 8.1 is my lowest gamble
forgot to add, no I’ve never seen anything happy at 7 Dkh

 

[ReefGeezer]

I would not think an alkalinity of 8 dKH would be the cause of burnt tips, even at higher PAR. Lower alkalinity needs have been associated with preventing burnt tips when carbon dosing. I don't have any ideas, but am following a I keep my Alk around 8 dKh.

 

[Nick Steele]

I’m assuming you know you can’t run your alk long term at 7…
what test kit are you using and how old are the reagents ?
either way I’d confirm my alk reading and slowly raise it to NSW if you got the nerve, …. IME 8.1 is my lowest gamble
forgot to add, no I’ve never seen anything happy at 7 Dkh

Why can’t you run a tank long term at 7 dkh?

 

[ocncheffy]

I’m assuming you know you can’t run your alk long term at 7…
what test kit are you using and how old are the reagents ?
either way I’d confirm my alk reading and slowly raise it to NSW if you got the nerve, …. IME 8.1 is my lowest gamble
forgot to add, no I’ve never seen anything happy at 7 Dkh

I tested my alk with 3 other kits, Hannah, Nyos, and Aquaforest which comes with a reference solution.

 

[jfoahs04]

Why can’t you run a tank long term at 7 dkh?

I'm curious too. I run my tank at 7 dkh and it's the default alkalinity of natural sea water.

 

[ocncheffy]

Some backstory:

A year ago I let my phosphates rise to .4ppm and ran alkalinity of around 8-8.5 at the time. I then decided to slowly drop my phosphates down to .1-.15 in hopes of increasing growth. Issues started a few months after this change in mid 2021. However, at .4 my tank looked amazing and SPS were taking off quickly. Could it simply be that my tank doesn't like having such low Orthophoshates (Hannah ULR Testing) and the balance was better when it was at .4? I know Mark from SaltwaterAquarium runs his phosphates at .5ppm and has crazy growth.

I don't know if I should go down the road again of simply letting my phosphates do what they want, yet that is also when my tank looked it's best... Thoughts?

 

[Nick Steele]

Some backstory:

A year ago I let my phosphates rise to .4ppm and ran alkalinity of around 8-8.5 at the time. I then decided to slowly drop my phosphates down to .1-.15 in hopes of increasing growth. Issues started a few months after this change in mid 2021. However, at .4 my tank looked amazing and SPS were taking off quickly. Could it simply be that my tank doesn't like having such low Orthophoshates (Hannah ULR Testing) and the balance was better when it was at .4? I know Mark from SaltwaterAquarium runs his phosphates at .5ppm and has crazy growth.

I don't know if I should go down the road again of simply letting my phosphates do what they want, yet that is also when my tank looked it's best... Thoughts?

If all was good back at .4 phosphate I would just go back to what you were doing back then and see how tank reacts.

 

[ocncheffy]

If all was good back at .4 phosphate I would just go back to what you were doing back then and see how tank reacts.

Oh I've thought about it.. It took a lot of work and a lot of GFO to slowly bring down phosphates from .4ppm. Of course, the general consensus in the hobby is that .4 is much too high as well.

 

[spsick]

Some systems just need lower alkalinity to be happy. Absolutely nothing wrong with a dkh of 7. Ran a system at that for years with thriving coral.

 

[Dburr1014]

Why can’t you run a tank long term at 7 dkh?

I want to know also
My system is constantly running below 7 even tho I want it at 8. Really trying hard to keep it up.

 

[Drummingbaker2010]

So I've been fighting with some burnt tips/STN on my SPS with the following parameters:

Alk - 8.1
Calcium - 450
Phosphate - .1
Nitrate - 10
Mag - 1400

I understand that low nutrients of near 0 can cause burnt tips/STN in SPS, but I would have never thought that the levels posted above were considered low nutrients. Since dropping my alkalinity to NSW 7.0, most SPS have healed up nicely. My lighting is set up for around 200 PAR at the top of the rockwork, with dual XR15 G4 pro's and Reefbrite strips. This took me months to figure out, and an ICP test, but nothing conclusive came back. Has anyone else experienced similar issues with requiring Alkalinity at around 7.0?

Note - Testing of alk was done with Hannah, NYOS, and Aquaforest for triple confirmation


*Edit backstory:


Some backstory:

A year ago I let my phosphates rise to .4ppm and ran alkalinity of around 8-8.5 at the time. I then decided to slowly drop my phosphates down to .1-.15 in hopes of increasing growth. Issues started a few months after this change in mid 2021. However, at .4 my tank looked amazing and SPS were taking off quickly. Could it simply be that my tank doesn't like having such low Orthophoshates (Hannah ULR Testing) and the balance was better when it was at .4? I know Mark from SaltwaterAquarium runs his phosphates at .5ppm and has crazy growth.

I don't know if I should go down the road again of simply letting my phosphates do what they want, yet that is also when my tank looked it's best... Thoughts?

 

[Nick Steele]

Oh I've thought about it.. It took a lot of work and a lot of GFO to slowly bring down phosphates from .4ppm. Of course, the general consensus in the hobby is that .4 is much too high as well.

Yeah but each tank is different. I just watched a YouTube video where a guy is running his tank at .6 phos and 40-50 nitrates and has an amazing tank with growth! He is even experimenting with fragging scolys that are healing nicely.

 

[Drummingbaker2010]

if you have corals, your alkalinity seems low. You usually want it beteween 8-12, but ideally 9-11. Calcium levels look fine, have you dosed any iodine? I am trying to check on my alkalinity level as well now

 

[ocncheffy]

if you have corals, your alkalinity seems low. You usually want it beteween 8-12, but ideally 9-11. Calcium levels look fine, have you dosed any iodine? I am trying to check on my alkalinity level as well now

Alk was dropped on purpose to stop burnt tips/STN in my SPS colonies. ICP test didn't indicate an Iodine issue.

 

[Drummingbaker2010]

if you have corals, your alkalinity seems low. You usually want it beteween 8-12, but ideally 9-11. Calcium levels look fine, have you dosed any iodine? I am trying to check on my alkalinity level as well now

did you make any adjustments to the lighting schedule?

 

[Oregon Grown Reef]

Not sure where everyone is getting the info of 7 being too low and not being at natural seawater levels. http://reefkeeping.com/issues/2004-05/rhf/

Table 1. Parameters critical to control in reef aquaria.​
Parameter:	Reef Aquaria Recommendation:	Typical Surface Ocean Value:1
Calcium	380-450 ppm	420 ppm
Alkalinity	2.5-4 meq/L 7-11 dKH 125-200 ppm CaCO3 equivalents	2.5 meq/L 7 dKH 125 ppm CaCO3 equivalents
Salinity	35 ppt sg = 1.026	34-36 ppt sg = 1.025-1.027
Temperature	76-83° F	Variable2
pH	7.8-8.5 OK 8.1-8.3 is better	8.0-8.3 (can be lower or higher in lagoons)
Magnesium	1250-1350 ppm	1280 ppm
Phosphate	< 0.03 ppm	0.005 ppm
Ammonia	<0.1 ppm	Variable (typically <0.1 ppm)

 

[Drummingbaker2010]

I know it's natural for sea water, but I've seen a lot of tests that have shown up to 70 percent more growth between 9-11, if that's what you're looking to do, then most hobbyists would recommend between 9-11.

 

[Dburr1014]

if you have corals, your alkalinity seems low. You usually want it beteween 8-12, but ideally 9-11. Calcium levels look fine, have you dosed any iodine? I am trying to check on my alkalinity level as well now

But the fact is you don't want to run your alkalinity that high if you have lower nutrients. That will also cause burnt tips. So that blanket statement of alkalinity really doesn't apply in all cases.

 

[Oregon Grown Reef]

I know it's natural for sea water, but I've seen a lot of tests that have shown up to 70 percent more growth between 9-11, if that's what you're looking to do, then most hobbyists would recommend between 9-11.

That 70% increase in growth has nothing to do with whether or not you can keep a tank at 7 dKh long term or not. Before we tell people to make changes, make sure what we're telling them is correct. No need to raise alk if the corals started responding better at a lower dKh.