SPS Dominant: What do you keep your alaklinity at and why?

[Scorpius]

Okay SPS dominant guys and gals at what level do you keep your alkalinity at and why? Have you always ran it at this level or have you changed it to another level? I would like this to be a discussion on what you keep your alkalinity at and why.

The reason I ask is that I recently had a spike to 9.3 dkh in my system which has led to some tissue loss. With this incident I have lowered it to around 7.0 dkh and I have some Acropora with polyps extended that have alway had very little polyp extension. I know everyone does reefing differently and I'd like to see what other heavy SPS users are doing.

 

[Justfebreezeit]

7.6-8.0 because my salt mix is 8 dkh.

 

[tiggs]

I keep my alk in the 11.1 - 11.5 range, based on the nutrient levels my tank consistently has. I stopped doing the whole ULNS thing and chasing zeros a long time ago, so once my nutrient levels stabilized, I went with an alk range that lined up with them.

 

[Livinlocal]

Over the years I have noticed a correlation between alkalinity and nutrients. It seems with ULNS’s you want a lower alkalinity, And with a lot of nutrients in your system, higher alkalinity is suitable. I have a ULNS; my phosphates and nitrates are undetectable, and when I go over 8.5-9 my sps start to turn pale and loose polyp extension. This is just my own personal observation, but if the water parameters are all in check, and you have a higher amount of alkalinity, it almost seems that the corals grow too fast to up to take the nutrients in the water, which in turn makes sense to me why a higher alkalinity does not do well in UNLS’s.

 

[Waters]

I keep it around 8.4 due to my salt mix and my tank's lower nutrients.

 

[ksfulk]

6.8 dKH on average, because I run Zeovit. Been running there for two years. On the previous tanks, Ive run upwards of 9.0-9.5, but those tanks were not as long lived, so while there was growth, the data points are limited.

 

[hbrochs]

7.5 - 8 seems to be working
Using Tropic Marin Pro Reef salt that has Alk around 7.5

 

[happyhourhero]

I run around 7.6-8 now. Used to do 9 but feel like everything looks better if I run it a bit lower. I also feel like the wiggle room to keep it in an acceptable range.

 

[Surfzone]

7.5to 8.0 for me. Although my po4s (0.08)and no3 (4) levels are low it's not what I call ultra low how ever I'm using the red sea salt in the blue bucket and that's around where it mixes too. I was using the black bucket for a while but my corals wouldn't grow then slowly died off. Ever since I swapped salt and kept a lower dKH I have had fewer problems.

 

[Bob Weigant]

Mine always seem to happy in the 8 - 9 range. Its dipped to 6.5 every once in awhile but still every thing seemed fine

 

[Bpb]

More often than not, there will be a sweet spot for alkalinity depending on available nutrients and waste content in the water. I tend to just have better colors and growth when I keep nutrients and alkalinity on the lower end. Any time I let nutrients climb, growth slows to a stop and colors get bland. Any time I let alkalinity climb up past 8.0, I get brittle tissue and receding polyps. Been that way for years. 6.8-7.0 is always my target

 

[Phelipe's Ocean]

I know lighting is not the topic but it ties to my alkalinity. First 6 months I run my alk at 12 and high nutrient levels and T5 lighting at around 14k for crazy growth so everything fills in nicely. After that mark I switch to LED’s, drop nutrients to indectable, and bring my alk down to 7.

 

[jda]

6.6 to 7.0.

This is a bit of a tricky question, though since it is constantly falling. I have a CaRx which today is maintaining about a 6.8 dKh. In a month, this will be down to 6.5 as the corals grew and have more demand. ...so I will turn it up to where it is maintaining 7.0 and then wait for it to fall again.

I find that calcification is better with more NSW alk, phosphate and nitrate, but all three need to be low together. This gives me the fastest growth and brightest color with more contrast.

Once I learned how to lower alk in saltwater with Muratic Acid, I have been near NSW and never looked back. Gallons * dKh drop * .123 is the mls of Muratic Acid to use. It can take a day or two to drive off all of the CO2 that you create and raise the PH back up. Do not ever do this in a tank, but I do it every time with my freshly mixed setup.

FWIW - when I started doing this in 1992, I did not have a fuge and had nitrate around 5 and phosphate around .5 (so hard to test back then) and I could keep alk at 12 quite reasonably... but 12 did not work too well when the caluerpa (and later chaeto) started to keep my N and P around NSW levels.

 

[Chad3407]

Does everyone that’s running low alk also keep calcium low.

 

[jda]

425 to 440... or natural seawater level.

 

[Chad3407]

Do they both still get consumed in about the same amount.

 

[neupane00]

Alkalinity for me depends on nutrients. Which in turn depends on light. One system
I run high intensity sps , po4 at 0.09 and nitrate at 10-14. I run alk at 7.5 - 8

Another tank I have little lower intensity light , po4 at 0.02, nitrate at 3-5, alk at 7.

I get better growth with first tank with higher alk

 

[Chip]

In my spare tank I can't keep nitrates or phosphates. So therefore I have to have lower alk. At 7.8 to 8.1. l am adding nitrate daily. Or sps will lose there color.

 

[cracker]

Very revealing OP's I always thought those who keep acro's had higher alk . My reef experiment tank seems to stay at 7.6 . Thought the numbers would be higher . Thanks !

 

[Bpb]

Calcium and alkalinity get consumed by corals in the same amounts, but calcium doesn’t tend to carry some of the negative effects that alkalinity does when it is run high. Alkalinity is used for more metabolic processes than simply skeleton building.