plase help with alkalinity!

[ryanhayes96]

I bought a alkalinity test kit and mine is at 2 milli equivilant per liter( thats what the test says) It says that the alk in natural seawater is 2.5 milli equivilant per liter. I have recently had a colony of tricolor monti digi die on me, but my other acropora does fine,

Is that a low level?

could it have caused the death?

[jeffbrig]

2meq/L is definitely less than ideal, but unlikely to kill a coral in the short term. However, it is another form of stress, and pH may also be low since it is tied to alkalinity levels. Low alk also reduces the calcification rates (i.e. coral growth), so its always to your advantage to maintain it at good levels.

Most reefers target alkalinity levels higher than nsw. I tend to track alkalinity in dKH units (1meq = 2.8dKH). While natural seawater is 7dKH, you'll commonly see hobbyists set targets of 9dKH to as much as 12dKH. Personally, I shoot for about 10.

[MCsaxmaster]

Agreed, that won't in and of itself kill anything, but it can cause stress by letting the pH slide down to unfavorable levels (high alkalinity tends to favor high pH and vice versa) and will reduce the rate of calcifcation. I'd shoot for a minimum alkalinity of 2.5 meq/l with 3.5-4.5 preferable IMO. Oh, and for reference, seawater alkalinty tends to fall between 2.25-2.45 meq/l in the tropics. It can be slightly higher or lower depending on local conditions. For example, in an enclosed area with a lot of reef development the alkalinity might drop as low as 2.1 meq/l after a days worth of calcifcation. In areas with high salinity it might be as high as 2.5 meq/l.

Chris