High Alkalinity what does it really cause

[Randy Holmes-Farley Verified Community Expert]

A sodium bicarbonate or sodium carbonate solution will last longer than the plastic jug it is in.

 

[trio91]

ok thank you so much for the info and sorry for the questions....im sure it made you feel like you were on 60 minutes

 

[KoleTang]

Not sure what you mean by a sweat spot. If not a ULNS tank, it seems not not matter what the alk is (say, 7-11 dKH), but corals can grow faster at higher alk, if that is a goal.

I think what he is getting at is something along the lines of the Redfield Ratio. ie., "If my Alk is 9dKH (which translates to "x" estimated amount of Carbon), what level of N and P should I target to create a balance".

An ULNS has problems caused by, presumably, growth rate + lack of nutrition when the Alk is higher than ~8dKH. Does this affect translate into the "Normal Nutrient System" or "High Nutrient System" at all? (If I had a normal nutrient system and cranked the Alk up to 11dKH, would there be a difference?)

It seems like there should be some sort of ratio considering systems like Blu Coral that have the Alk at 16dKH and put in large amounts of food and amino acids to balance it out.

 

[bfam4t6]

I discuss the baking as part of a DIY two part here:

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

Wow, lots of awesome info here! Thanks Randy!

I'm glad I stumbled into this thread.

 

[Randy Holmes-Farley Verified Community Expert]

ok thank you so much for the info and sorry for the questions....im sure it made you feel like you were on 60 minutes

No problem. I've answered well over 100,000 reef chemistry questions in the past 20 years, so I'm used to it and have seen most possible questions already.

 

[Randy Holmes-Farley Verified Community Expert]

Wow, lots of awesome info here! Thanks Randy!

I'm glad I stumbled into this thread.

You're welcome.

Happy Reefing.

 

[glb]

I'm thinking of raising my alk from 9 up to 10. I did a 30% water change to lower nitrates (I know, too much at once), and my alk jumped up to 10 as a result. The corals look much happier at 10. I have soft corals, sps and lps and they all look better.

 

[maroun.c]

Wow this thread really kicked off!!!
Amazing how alkalinity still raises tons of questions each time.
the reason for me posting in this thread was a doser incident where I ended up dumping around 2 litres of part B in my tank in 2-3 days.
I run alk at 7.5-8 usually and recently it had jumped to 9.5 so dialed down my part B to 80 to let it drop back and stupid me set the doser to 800 instead of 80 ml per day:mad: so ended up with an alk of 13.4.(Good bless large water volume!) a couple of frags looked bad but most others looked at their best and for the first time I'm noticing growth and better colors on my SPS which haven't been doing good since the start of this tank.
I'm currently down to 11ish, will let it drop slowly to 9-10 and keep it there I guess as I don't run ULNS.

 

[cvicente]

I run my tank in the 10dKH range, my system has a .88ppm level of PO4 and 2.53 ppm level of NO3 (LaMotte colorimeter) I can't run NSW of alkalinity because the corals simply don't grow well because of the increased levels of Symbiodinium in their tissues that compete with coral for DIC.

 

[peter fumo]

So if I'm following correctly I should be between 9-11

 

[Randy Holmes-Farley Verified Community Expert]

I run my tank in the 10dKH range, my system has a .88ppm level of PO4 and 2.53 ppm level of NO3 (LaMotte colorimeter) I can't run NSW of alkalinity because the corals simply don't grow well because of the increased levels of Symbiodinium in their tissues that compete with coral for DIC.

That certainly seems fine to me.

 

[peter fumo]

So you wouldn't recommend using limewater or you wouldn't recommend using caulk long-term and also does limewater at magnesium?

 

[Randy Holmes-Farley Verified Community Expert]

I do recommend using limewater in general. It's all I've used for calcium and alkalinity for 20 years on my system.

But if calcium is already 600 ppm, then I'd use just an alkalinity supplement and no calcium until it declines a bit.

Limewater does not add significant magnesium, regardless of some claims otherwise. Magnesium is insoluble in limewtaer.

 

[cvicente]

I currently use a Kalk stirrer connected to the ATO, a CaCO3 reactor (GEO CR612 with natural coral rubble) and Mg dosing (Ions Aquavitro)

 

[dragonfish]

following !

 

[Aliasger]

My alkalinity is 14dkh and calcium is 460ppm. Do i need to reduce my alkalinity? As i have been reading alot about this topic. My pH is 8.4. So far haven't had problems with fish but i am planning to keep corals. So do i need to bring it down? I use natural seawater and my tank is 5000 Gallons

 

[Randy Holmes-Farley Verified Community Expert]

My alkalinity is 14dkh and calcium is 460ppm. Do i need to reduce my alkalinity? As i have been reading alot about this topic. My pH is 8.4. So far haven't had problems with fish but i am planning to keep corals. So do i need to bring it down? I use natural seawater and my tank is 5000 Gallons

As I mentioned earlier in the thread, there are a few main things higher alk does. Whether you want to lower it or need to lower it depends on whether those things are a net plus for you, or a a net negative (which may depend on your nutrient levels and types of corals you keep):

There are a variety of things that high alkalinity does.
First, it increases the likelihood of precipitation of calcium carbonate on things like pumps, heaters, and sand.

Second, it spurs some hard corals and coralline algae to grow faster since getting enough carbonate can be a rate limiting step in calcification (skeletal growth).

Finally, some SPS corals in a very low nutrient environment with high alkalinity may suffer "burnt tips", which might be due to the tissue being unable to keep up with the skeletal growth, leaving very thin tissue which might be more susceptible to burning by high light/UV levels.

Corals that have issues with alk swings may be suffering from a temporary mismatch between their ability to take up bicarbonate and the internal demand for it.

 

[CavalierReef]

So much information and so little comprehension on my part. Thank you for taking the time to provide your expertise sir. I know it is in this thread somewhere but how do you actually lower alkalinity other than with an acid. My Ca is 440, my Mg is 1450 and my Alk is 14.9. How do I get to 9-10 or do I want to. Relatively new 30 g tank with only 2 hammers and xenia as the coral occupants so far. Thank you.

 

[nereefpat]

how do you actually lower alkalinity other than with an acid. My Ca is 440, my Mg is 1450 and my Alk is 14.9. How do I get to 9-10 or do I want to.

Make sure that you aren't inadvertently adding alkalinity by dosing "buffer" or something.

After that, you can let it come down on its own. This may take a while, depending on the tanks alk demand. Coralline algae will consume alk.

After that, the only way to lower alk without adding an acid would be to do water changes with a lower alk salt. Alk of Make-up saltwater can be lowered with acid...just give it a day or so for pH to come back up.

 

[Randy Holmes-Farley Verified Community Expert]

So much information and so little comprehension on my part. Thank you for taking the time to provide your expertise sir. I know it is in this thread somewhere but how do you actually lower alkalinity other than with an acid. My Ca is 440, my Mg is 1450 and my Alk is 14.9. How do I get to 9-10 or do I want to. Relatively new 30 g tank with only 2 hammers and xenia as the coral occupants so far. Thank you.

As noted above, the only alternatives are a mineral acid (not vinegar), water changes with a low alk mix (you can make it lower than normal, say 2 dKH), or letting it fall on its own.