What is the ideal alkalinity

Salty_Box_Reef · Apr 15, 2017

I've been keeping around 9.0-9.5 with great growth in my sps's. however I don't have that great of colors. Would I see a increase in colors if I slowly dropped my alk? I feed real heavy and don't plan to run a ulns so I never really planned to run my alk below about 8.6/8.7 range until recently where I've been struggling to get my acros the colors I want, which is deeper and richer as oppose to the lighter more pastel colors im getting.

Centerline · Apr 17, 2017

BryanB said:
I have kept my tank at 10.4 or so because I was understanding it would be rapid growth ( Red Sea rapid growth calls for 12.?) I had a conversation yesterday at reefapalooza that made me think dropping it to about 7.8-8.2. What are your thoughts?

I have ran my alk between 10-12 for last 10 or so years (when Red Sea Coral Pro started to get popular) and can promise you that when everything else is right corals grow faster with elevated alk, cal and mag. The problem is as Randy mentioned above this doesn't seem to work very well in ULN tanks. If you go higher than 10 be prepared to test a lot. My experience leads me to believe that with higher alk levels the bacterial populations of the tank can get out of control pretty quickly by having more carbonate to consume and start driving nutrients nd 02 down pretty dam fast. And as others have said, with low N&P and high alk your corals may stop growing, turn pale and tips may burn. A good route to go might be to use something like the Red Sea's Reef Energy products to keep your levels up. And again, in my experience you should be prepared to test a bunch anyway. 9-9.5 might be a workable compromise, less maintenance and rapid growth.

Randy Holmes-Farley · Apr 17, 2017

Ssteve said:
I've been keeping around 9.0-9.5 with great growth in my sps's. however I don't have that great of colors. Would I see a increase in colors if I slowly dropped my alk? I feed real heavy and don't plan to run a ulns so I never really planned to run my alk below about 8.6/8.7 range until recently where I've been struggling to get my acros the colors I want, which is deeper and richer as oppose to the lighter more pastel colors im getting.

I'm not sure.

I would speculate that it won't change the color, but it is easy enough to try.

Hans-Werner · Apr 18, 2017

In my experience and to my best knowledge:
- Phosphate is more important to rapid growth of SPS, especially Acropora spp., than alkalinity.
- Alkalinity will be higher in tanks with higher phosphate concentrations because phosphate inhibits calcium carbonate precipitation. This may look like more rapid growth is caused by higher alkalinity when in fact it is caused by higher phosphate concentrations.
- High alkalinities in tanks with ultra low phosphate concentrations cause less polyp extension and rather less growth of SPS than faster growth. Corals look stressed. "High" alkalinity may be as low as 8° KH in an ULNS.
- There is no general ideal alkalinity, it depends on what is preferred or tolerated by the corals in a specific tank. Alkalinity must fit to the phosphate concentrations and the corals. Both, high and low alkalinities may have adverse effects to corals and coral growth.
- Natural "normalized" (to 35 psu salinity) alkalinity is only around 6.5° KH in the oceans all over the world (Millero).

Want2BS8ed · Apr 21, 2017

Hans-Werner said:
In my experience and to my best knowledge:
- Phosphate is more important to rapid growth of SPS, especially Acropora spp., than alkalinity.
- Alkalinity will be higher in tanks with higher phosphate concentrations because phosphate inhibits calcium carbonate precipitation. This may look like more rapid growth is caused by higher alkalinity when in fact it is caused by higher phosphate concentrations.
- High alkalinities in tanks with ultra low phosphate concentrations cause less polyp extension and rather less growth of SPS than faster growth. Corals look stressed. "High" alkalinity may be as low as 8° KH in an ULNS.
- There is no general ideal alkalinity, it depends on what is preferred or tolerated by the corals in a specific tank. Alkalinity must fit to the phosphate concentrations and the corals. Both, high and low alkalinities may have adverse effects to corals and coral growth.
- Natural "normalized" (to 35 psu salinity) alkalinity is only around 6.5° KH in the oceans all over the world (Millero).

Hans-Werner, do you have a suggested range of phosphate levels? What about Nitrates? Do you see an ideal ratio of Phosphates vs Nitrates vs Alkalinity?

I have a relatively new tank (6 months old), I would like to drive some initial growth in, even at the expense of color. What is the opposite of a ULNS? UHNS (Ultra High Nutrient System) or do we call that an algae farm?

Appreciate the input.

M

Cory · Apr 22, 2017

Since test kits can fail i keep mine at 9.5dkh since it gives room for the max and minimum drift.

The GARDENER · May 12, 2017

7 to 8 DKH IN my system

Gonzo74 · Oct 4, 2018

revhtree said:
I'm trying to keep mine around the 9-10 DKH range for now.

What do you keep your Calcium, Magnesium, Phos and Nitrates at? I am also trying to find my balance and have been using the recommended dosing that Red Sea recommends for a Mix reef and things are dying off in these levels.

Sean1986 · Oct 4, 2018

Gonzo74 said:
What do you keep your Calcium, Magnesium, Phos and Nitrates at? I am also trying to find my balance and have been using the recommended dosing that Red Sea recommends for a Mix reef and things are dying off in these levels.

Hey gonzo, are you testing your alk, calcium? Or just going off the recommended dose for the size tank and style?

Gonzo74 · Oct 4, 2018

Sean1986 said:
Hey gonzo, are you testing your alk, calcium? Or just going off the recommended dose for the size tank and style?

I test with Red Sea Pro test kits and then add based on results and volume of water in tank. I just don’t know where my base should be at. Do I do high or low Alkalinity? Right now, my Frog Spawn and Hammers are looking rough.

Sean1986 · Oct 4, 2018

Couple things,

For me I hate the Red Sea Alk test kit, I prefer the Hannah. I used Red Sea for years for me there is to many human errors for the test kit.

I’d check calcium and also make sure you have some nitrate and phosphate in your tank. Softies do not like super clean tanks.

And high or low alk depends on how clean your tank is a ultra low nutrient tank should have lower alk.

A high nutrient tank should have higher alk

If I am remembering correctly

scardall · Oct 4, 2018

Sean1986 said:
Couple things,

For me I hate the Red Sea Alk test kit, I prefer the Hannah. I used Red Sea for years for me there is to many human errors for the test kit.

I’d check calcium and also make sure you have some nitrate and phosphate in your tank. Softies do not like super clean tanks.

And high or low alk depends on how clean your tank is a ultra low nutrient tank should have lower alk.

A high nutrient tank should have higher alk

If I am remembering correctly

This would explain ULNS, Alk. being so low (5.3dkh to 7dkh) NO3 .25ppm and PO4 .03ppm I add 40-50ml Twice a day of soda ash. so low is 6-6.5dkh when I dose like this. Annoying really. I still have cyno, even with descent flow thru out 95% of the tank. I can dose chemiclean to clean it up, but it always returns within a week. For now why bother, just blow it loose from time to time.