How to Maintain Extra-High Alk ??

[jacko]

Hi Randy, Another Alk/Ca/Mg question -- your favorite!

I have had no trouble maintaining my Ca/Alk levels with the 2 part DIY system (set-point = 450 ppm & 4 meq/L). Great system, thanks. See Attached.

Over the last several months, I have been battling Bryopsis... In addition to using a bigger skimmer, and feeding less, people have recommended high alkalinity levels for stunting this algae's growth. You can see in the attached picture that in September I started increasing my Alk, and concurrently, my Ca has been very difficult to maintain. There is more precipitate than usual.

Can you comment on maintaining high Alk? Should I try to keep high Calcium as well, or can I let the Ca slide... and target 5 meq/L and 400 to 450 ppm Ca? What do you think is the highest safe level for my Alk? And finally, does the 2-part DIY system limit my ability to keep these levels high up in region #1? Is there a better way? THANKS!

Oh, with respect to Mg, I try to target 1300 to 1350....but I often find that I maintain 1280 to 1320.

[Randy Holmes-Farley]

The easiest way for you to maintain high alkalinity is via low pH. However, I do not know if that combination will help bryopsis or not. Normal to high magneisum may also help with the goal of elevating alkalinity.

The two part additives are a good way to go, IMO. Use a low pH version, such as my DIY using normal baking soda, or B-ionic Bicarbonate.

My guess is that the high alkalinity is driving the growth of things that compete with bryopsis for nutrients (corals, coralline algae, etc). So I'd suggest that you need to maintain normal calcium as well.

Going after teh nutrients directly may also be effdective. Phospahte especially. Maybe an iron oxide type.

These articles may help:

Iron Oxide Hydroxide (GFO) Phosphate Binders
http://reefkeeping.com/issues/2004-11/rhf/index.htm

Phosphorus: Algae’s Best Friend
http://www.advancedaquarist.com/issues/sept2002/chem.htm

[jacko]

cool, thanks, Randy.
Another question -- would you expect to see so much scatter in my data? Am I maintaining these params tightly, or is this variability unhealthy? This leads to the important question of how consistent are my test kits, and I don't have a good answer for that one. (I assume you are able to see the attached graph).

[Randy Holmes-Farley]

If you are trying to push the limits of calcium and alkalinity with unbalanced additives, that would widen the fluctuations, so it isn't too surprising. I don't think the variability, especially since Dec 9, is a concern.

[mhurley]

FYI if you didn't know, Calfo advocates a high pH (8.6) as a potential bryopsis killer.

http://archive.reefcentral.com/forums/showthread.php?postid=3919145#post3919145