Where do you keep your Alk, and Why??

[CalmSeasQuest]

Andy,

Do you think it's the higher Alk level per se, or Alk swings that pose the greatest problems (assuming no Carbon dosing)?

I run Alk toward the higher end of the range (~10 dKh) but with very little variation and have had no problems with SPS.

I'd be curious to know what values firms such as LiveAquaria/DD use in their holding an QT systems. I'm sure the shock of going from 8 to 10+ dKh could have adverse affects.

[schminksbro]

Originally Posted by CalmSeasQuest

Andy,

Do you think it's the higher Alk level per se, or Alk swings that pose the greatest problems (assuming no Carbon dosing)?

I run Alk toward the higher end of the range (~10 dKh) but with very little variation and have had no problems with SPS.

I'd be curious to know what values firms such as LiveAquaria/DD use in their holding an QT systems. I'm sure the shock of going from 8 to 10+ dKh could have adverse affects.

I think swings are definitely the most detrimental. However when acquiring a newly imported coral whether it be wild or maricultured you are taking a risk introducing it to a carbonate level that is substantially higher than NSW levels. In essence you are subjecting the coral to an immediate alk swing which in today's day and age is totally avoidable. IMHO running your alk at 10,11, or even 12dkh is an extremely antiquated method. Afterall why would we possibly want to deviate from NSW levels when we don't have to and we know better? There are many aspects of ocean life that we cannot (at this time) duplicate but alk and calcium levels don't fall under that category. When possible I prefer to approximate natural conditions that the animals we keep have grown accustomed to over millenia.

[jimsflies]

Here is an excerpt from a Randy Holmes-Farley article on water parameters:

Unlike the calcium concentration, it is widely believed that certain organisms calcify more quickly at alkalinity levels higher than those in normal seawater. This result has also been demonstrated in the scientific literature, which has shown that adding bicarbonate to seawater increases the rate of calcification in Porites porites.4 In this case, doubling the bicarbonate concentration resulted in a doubling of the calcification rate. Uptake of bicarbonate can apparently become rate limiting in many corals.5 This may be partly due to the fact that both photosynthesis and calcification are competing for bicarbonate, and that the external bicarbonate concentration is not large to begin with (relative to, for example, the calcium concentration).

For these reasons, alkalinity maintenance is a critical aspect of coral reef aquarium husbandry. In the absence of supplementation, alkalinity will rapidly drop as corals use up much of what is present in seawater. Most reef aquarists try to maintain alkalinity at levels at or slightly above those of normal seawater, although exactly what levels different aquarists target depend a bit on the goals of their aquaria. Those wanting the most rapid skeletal growth, for example, often push alkalinity to higher levels. I suggest that aquarists maintain alkalinity between about 2.5 and 4 meq/L (7-11 dKH, 125-200 ppm CaCO3 equivalents), although higher levels are acceptable as long as they do not depress the calcium level.

More can be read here.

I agree with Andy in terms of alk/pH swings with newly added stock...maintaining sea water alkalinity levels will be one less variable to deal with. But if someone is not adding new stock and wanting to maximize growth of stoney corals, there may be some logic to keeping an elevated alkalinity level due to the fact that growth rates have been shown to improve as a direct relationship to alkalinity (bicarbonate) concentration.

[MizTanks]

Love this info!!!

[ROGERWILCO357]

do corals like sps acro's grow faster in higher or lower alk? has anyone noticed a spike in growth when at a certain level?

[rosebud161616]

I notice spikes in growth when my alk is stable, not so much at a certain level.