How do I pick my goal # for ALK?

[Lionsreef]

In general, if you want faster skeletal growth of hard corals, higher alk and higher nutrients (sufficient N and P of some form) to go along with it. Maybe 10-12 dKH.

If you keep nutrients lower for any reason (or you just don't measure them so they may be low or get low), then lower alk (say, 7-8 dKH) is better since higher alk and lower nutrients can lead to SPS burnt tips (which may be due to the skeleton growing faster than tissue can keep up).

If you are keeping primarily LPS and soft corals and anemones and such, I'm not sure the alk value matters much within the normal range of about 7-11 dKH.

When you say higher alk goes with higher nutrients is there a rule of thumb? I have been using IO reef crystals which I know has higher alk but I like it in that I don't have to worry about mag or Calcium dosing. I only dose ALK and maintain the tank easily around 9.5 dkh and do 20% water changes every other weekend. I have a mixed reef of SPS and LPS. My fish load is dominated by a dwarf lion that I feed ghost shrimp resulting in PO4 of 0.04 to 0.05 on a hanna ULR phosphorus checker and NO3 around 10-15. Is this a good target for my nutrient levels?

 

[Randy Holmes-Farley]

When you say higher alk goes with higher nutrients is there a rule of thumb? I have been using IO reef crystals which I know has higher alk but I like it in that I don't have to worry about mag or Calcium dosing. I only dose ALK and maintain the tank easily around 9.5 dkh and do 20% water changes every other weekend. I have a mixed reef of SPS and LPS. My fish load is dominated by a dwarf lion that I feed ghost shrimp resulting in PO4 of 0.04 to 0.05 on a hanna ULR phosphorus checker and NO3 around 10-15. Is this a good target for my nutrient levels?

Those values are fine, unless the corals seem brownish (and then only if that concerns you), which is why, in general, people often opt for lower nutrients and less zoox levels in the corals.

I don't think we have a perfect understanding of such interrelationships, but if the source of N is nitrate, then something in the range of 1-5 ppm seems adequate for alk up to about 11 dKH. As you push higher, more may be needed, or different sources (ammonia, amino acids, etc.). As to phospahte, 0.02 to 0.03 ppm usually seems sufficient, but again, at the high end, I'm not sure where (if) that may become an issue.

 

[Fourstars]

Three big mistakes I always seem to make. Chasing numbers and never letting things get stable, the first year of my tank this was a big issue. Second is NOT chasing numbers because it all looks so good and I finally have the tank dialed in ( Small bodies of water are not prone to stability} And third is making assumptions, I assumed that the great growth I was seeing, and the issue of my soft corals not opening was the high ALK. but last night I found my caulerpa had gone asexueral and turn white. So maybe the influx of nutrients and the high alk caused the stoneys to take off, but the die off toxins caused issues with the soft bodies?

 

[BigJohnny]

I think in general you will have the best chance of success at 7-8.5 dkH. Just my opinion, but you don't have to look at too many of the best tanks in the world to see that they run the same.

Imo there are more risks at higher dkH especially with acropora

 

[John3]

I run similar nutrient levels and radion g4 led lighting and I like my alk 11-12. I have mostly lps and softies and everything grows the best for me with the higher alk.

 

[pdiehm]

As my sps tank develops, i have been advised to run at 8dkh. Now, I also use regular instant ocean (you just can't beat $42 for 200 gallons + $20 for 50 lbs of calcium chloride, which I think will last me a very long time).

My nutrients as of sunday were 2-3ppm NO3, 0.00 PO4, and 1440 Magnesium, to go with 9.8 dkh, and 8.28 pH.

Long story short, I was told, since I'm not quite ULNS, but rather just a low nutrient system, I need to run my alk at 7-8dkh. Is that right? I have no idea. I would like to run my tank at the IO level dkh, but, I also may not have the nutrients to do so. I really do not want to shell out almost twice the cost of IO for Red Sea blue bucket, which is a fine salt, but if I can get the same results from $42/200 gallons, and experts such as WWC, Jason Fox, and our own Randy use/used it...why shouldnt I? Tonight my tank tested at 9.3dKh

If I understand right, the more nutrients you have, the higher alk you want. Lower nutrients the lower alk.

 

[pdiehm]

As my sps tank develops, i have been advised to run at 8dkh. Now, I also use regular instant ocean (you just can't beat $42 for 200 gallons + $20 for 50 lbs of calcium chloride, which I think will last me a very long time).

My nutrients as of sunday were 2-3ppm NO3, 0.00 PO4, and 1440 Magnesium, to go with 9.8 dkh, and 8.28 pH.

Long story short, I was told, since I'm not quite ULNS, but rather just a low nutrient system, I need to run my alk at 7-8dkh. Is that right? I have no idea. I would like to run my tank at the IO level dkh, but, I also may not have the nutrients to do so. I really do not want to shell out almost twice the cost of IO for Red Sea blue bucket, which is a fine salt, but if I can get the same results from $42/200 gallons, and experts such as WWC, Jason Fox, and our own Randy use/used it...why shouldnt I? Tonight my tank tested at 9.3dKh

If I understand right, the more nutrients you have, the higher alk you want. Lower nutrients the lower alk.

 

[BigJohnny]

As my sps tank develops, i have been advised to run at 8dkh. Now, I also use regular instant ocean (you just can't beat $42 for 200 gallons + $20 for 50 lbs of calcium chloride, which I think will last me a very long time).

My nutrients as of sunday were 2-3ppm NO3, 0.00 PO4, and 1440 Magnesium, to go with 9.8 dkh, and 8.28 pH.

Long story short, I was told, since I'm not quite ULNS, but rather just a low nutrient system, I need to run my alk at 7-8dkh. Is that right? I have no idea. I would like to run my tank at the IO level dkh, but, I also may not have the nutrients to do so. I really do not want to shell out almost twice the cost of IO for Red Sea blue bucket, which is a fine salt, but if I can get the same results from $42/200 gallons, and experts such as WWC, Jason Fox, and our own Randy use/used it...why shouldnt I? Tonight my tank tested at 9.3dKh

If I understand right, the more nutrients you have, the higher alk you want. Lower nutrients the lower alk.

You can add muriatic acid to lower the dkh of instant ocean.

 

[pdiehm]

You can add muriatic acid to lower the dkh of instant ocean.

Could. I use the stuff for my pool, but it’s nasty. I am not all that concerned with the alkalinity as a whole of IO because a 10% change doesn’t affect it too much though at 8dkh my calculation is a 0.7 increase vs at 9.0 doh it’s 0.2.

But with low nutrients it seems the lower alk is necessary/required.

What is the ratio of HCl per 5g?

Edit: looks like 1.4ml per 5 gallons to take 10.4 to 8.

So would mix it, then next day test, add the HCl and mix for another day (or aerate, add baking soda?) then do water change.

 

[BigJohnny]

Could. I use the stuff for my pool, but it’s nasty. I am not all that concerned with the alkalinity as a whole of IO because a 10% change doesn’t affect it too much though at 8dkh my calculation is a 0.7 increase vs at 9.0 doh it’s 0.2.

But with low nutrients it seems the lower alk is necessary/required.

What is the ratio of HCl per 5g?

Edit: looks like 1.4ml per 5 gallons to take 10.4 to 8.

So would mix it, then next day test, add the HCl and mix for another day (or aerate, add baking soda?) then do water change.

I'm not your guy I don't do it, but search there are plenty of threads about it.

 

[Tautog]

Oops

 

[Tautog]

Oops

 

[BigJohnny]

FWIW, I totally agree with Randy, and have seen this first hand. I try to keep Alkalinity between 7.5 - 8.5. I keep a high nutrient level. Not all, but most SPS corals are growing faster than the coral can cover with tissue. I use Reef Crystals which mixes out at 12.5 dKH, and after 10-14 days of dosing 300 ml/day/ 2- part, my Alkalinity drops to 7. After the WC, I’m back up to 8.5 dKH. If my Alkalinity doesn’t drop enough, or tests at 8.0 dKH or above before a WC, I wait a day or two. I’ve read Jason Fox does the same thing. It works for him, and it’s working for me!

Are you saying you have a 1.5 dkH swing everytime you do a water change?

 

[Randy Holmes-Farley]

As my sps tank develops, i have been advised to run at 8dkh. Now, I also use regular instant ocean (you just can't beat $42 for 200 gallons + $20 for 50 lbs of calcium chloride, which I think will last me a very long time).

My nutrients as of sunday were 2-3ppm NO3, 0.00 PO4, and 1440 Magnesium, to go with 9.8 dkh, and 8.28 pH.

Long story short, I was told, since I'm not quite ULNS, but rather just a low nutrient system, I need to run my alk at 7-8dkh. Is that right? I have no idea. I would like to run my tank at the IO level dkh, but, I also may not have the nutrients to do so. I really do not want to shell out almost twice the cost of IO for Red Sea blue bucket, which is a fine salt, but if I can get the same results from $42/200 gallons, and experts such as WWC, Jason Fox, and our own Randy use/used it...why shouldnt I? Tonight my tank tested at 9.3dKh

If I understand right, the more nutrients you have, the higher alk you want. Lower nutrients the lower alk.

I don't think there's any requirement for low nutrients at low alk (6-8 dKH). It is just that you CAN have low nutrioents there and not at high alk with SPS.

Depending on how you measured phosphate (meaning if the kit could have detected 0.01-0.02 ppm accurately), it may be too low at 0.00 ppm to permit high alk with SPS.