Effects of Low Alk on a System
Printed From: Utah Reefs
Category: Specialized Discussion
Forum Name: Reef Chemistry
Forum Description: A place to discuss reef chemistry.
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=44957
Printed Date: July 09 2026 at 11:30am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com
Topic: Effects of Low Alk on a System
Posted By: Snowsrfr
Subject: Effects of Low Alk on a System
Date Posted: November 24 2010 at 11:01pm
|
What kind of effects would one expect to see, or has been observed in your tank with low alkalinity but proper Ca levels? ------------- "A fish tank is not a pet. It's a TV that you gotta feed." - John Caparulo |
Replies:
Posted By: SGH360
Date Posted: November 24 2010 at 11:07pm
| PH drop will be the first thing you will see, it will be in constant level |
Posted By: tcfab
Date Posted: November 24 2010 at 11:08pm
|
How low is low? ------------- Need custom acrylic work? give me a call, www.Elite-Aquatics.net (801)645-6386 |
Posted By: Ryan Thompson
Date Posted: November 24 2010 at 11:14pm
|
Certain corals don't open up as large for me and polyp extension isn't as great. But how low is low like Tyler said?
|
Posted By: Snowsrfr
Date Posted: November 24 2010 at 11:17pm
|
Before I say how low is low, I wanted to get peoples unbiased opinions on what they have seen, or what I should be seeing. So far SGH360 may be on to something because I've had issues with my pH reading low on my APEX. ------------- "A fish tank is not a pet. It's a TV that you gotta feed." - John Caparulo |
Posted By: Snowsrfr
Date Posted: November 24 2010 at 11:26pm
|
Well, since I just got confirmation that the written instructions were incorrect while my card showed the proper ratio of drops to dkH from the Elos mod over on RC, my dkH is 5-6 when the whole time I thought it to be 10-11. ------------- "A fish tank is not a pet. It's a TV that you gotta feed." - John Caparulo |
Posted By: jwoo
Date Posted: November 25 2010 at 12:38am
|
5-6 is low but not super duper bad, pretty easy to turn that around. I only keep mine at 8-9 so really your only 2-3 below what I usually keep it at. I do notice if it drops below 8 that my corals look real crappy. No poly extensions. My zoos don't open up. Acans get really small looking. ------------- None at the moment Soon: 72 Gallon Bowfront |
Posted By: bstuver
Date Posted: November 25 2010 at 12:48am
|
My alk was really low on my tank and I am thinking that may have been what started my poor starfish getting necrosis:( He however is on the mend. But I agree certain corals won't open up and they just don't look as good.
------------- Jackie Stuver "wait these aren't the happy Hawaiians oompa doompa godly heaven on your face zoas? I dont want them then. lol!" Ksmart |
Posted By: Snowsrfr
Date Posted: November 25 2010 at 1:29am
|
That's the odd thing. All corals look good. ------------- "A fish tank is not a pet. It's a TV that you gotta feed." - John Caparulo |
Posted By: SGH360
Date Posted: November 25 2010 at 3:04am
| Is probably because the change was slow that corals have little impact on the change. This can probably start causing damage in the long run, i would raise it as soon as possible before they start to retract |
Posted By: Mark Peterson
Date Posted: November 25 2010 at 8:13am
|
I agree with everyone that has posted. If you think about it, almost every organism in the tank uses Calcium in some form, from SPS skeleton, fish bones, worm tubes, to Coralline Algae. Soft coral make sclerites, calcium slivers that give it it's structure. Snails need Alkalinity and Calcium to make shells. Crab, shrimp and "pods" need to make their exoskeletons. In fact, even all soft tissues have a Calcium or Calcium Carbonate component. It's actually very nice to see the high level of understanding of the importance of Alkalinity, but... It has been my observation that Calcium can do nothing without Alkalinity and vise-versa, Alkalinity can do nothing without Calcium. If either one is below an acceptable level, growth is inhibited. If left unaddressed, death will eventually follow. It is definitely a gradual and often unnoticable decline. This is the reason that Alk and Ca testing are as important as Temperature and Salinity. My learning experience is this area caused the end of my 18 month no-water-change experiment. I could not keep Hermits alive. I thought the large Six-line Wrasse was killing them so I got rid of that fish, but the Hermits still died. I wish I could remember how or who it was that pointed me to Alkalinity and Calcium testing, because that changed everything. The coral (soft only) which I had not noticed until the end, had stopped growing, thankfully began to recover. My best guess is that Alk or Ca or both had been below range for a year. It took 6 months for the tank to return to good health. Just a note regarding a comment posted above. Natural seawater is said to have an Alkalinity of 8 dKH. I can't remember what the Calcium number is, maybe 350 ppm. Even after all the effort we put into them, our little aquariums still fall short of the natural ocean in so many known and unknown ways. If we keep Alk and Ca at the level of natural seawater, we are limiting our aquariums to a much narrower range of conditions. When, not if, Alk, Ca or some other still unknown parameter goes awry, our tank is placed at great risk. I find it very sensible to keep Alk and Ca higher than natural seawater. We have found that Alk of about 10 and Ca of 425 (midrange) are actually healthy. Perhaps this is because such favorable Alk and Ca compensate for, or at least help the aquarium pass safely through, other negative conditions.  ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member 
|
Posted By: Ryan Thompson
Date Posted: November 25 2010 at 10:11am
|
Mark,
Nsw has a dkh of 7 and a calcium of around 420. I believe magnesium is right around 1350. Randy Holmes-Farley wrote an article talking about how organisms can uptake more calcium when the alkalinity is around 7. He stated that an acceptable range for our tanks is between 7-11dkh. I know you know the range as you have mentioned it many times. Just thought it was good to share. |
Posted By: Snowsrfr
Date Posted: November 25 2010 at 10:17am
|
Added an extra shot of alk last night after all this and I already see a difference in my pH. Normally has an overnight low of around 7.8'ish (RDP refugium), but last night stayed just above 8. ------------- "A fish tank is not a pet. It's a TV that you gotta feed." - John Caparulo |
Posted By: Mark Peterson
Date Posted: November 25 2010 at 10:28pm
|
I've read Alk of natural seawater listed as 8 dKH. I disagree with Randy. When I see comments like jwoo/Justin's I know that maintaining the Alk at a higher level is more helpful. Add to that what I said above about a tank with Alk at an artificially higher level being better able to weather adverse conditions. ------------- Reefkeeping Tips, & quick, easy setup tricks: www.utahreefs.com/forum/forum_posts.asp?TID=9244 Pay it forward - become a paid WMAS member
|
Posted By: Chris Scott
Date Posted: November 26 2010 at 12:02pm
I had low alkalinity for a long time in my tank. My calcium was always high because of the salt I used. What I saw was poor to no growth in all but my xenia corals. Acans/Zoo's/SPS all stayed alive and healthy, but never grew. I then started testing for it and dosing it in topoff and things are starting to grow. I could probably still get more growth if I spot fed things, but eh, I guess I'm a bit lazy there.  Also I had almost zero coralline until I controlled my alk. ------------- 55g Bowfront Corner Reef |