PH and Alkilinity

[goodisor]

Hi All,

I have tested my PH 8.1,Alkilinity 3,salinity 1.023.Is this good?What should it be ideally?

Goodisor

 

[Anonymous]

If you are keeping coral......salinity (SG) should be 1.025 (avg). Ph....8.0-8.2.

I really don't know about alk.

 

[gate]

what about calcium?
is 400 (+/- 10) ok?

 

[shavo]

my test kit advises to be between 480 and 520 on calcium

 

[ChrisRD]

Assuming your Alk reading is in meq/L your numbers look OK to me, although I agree with Crissy that your SG is a bit low for a reef tank (if you're just keeping fish it's fine).

The generally accepted numbers for natural seawater are as follows:
pH = 8.2
Ca = 420 ppm
Alk = 7dKH (2.5 meq/L)
SG = 1.0264 @ 25 degrees C (77 degrees F)
S = 35 ppt (these days referred to as 35 PSU)

IME there is really no benefit to maintaining levels much different than these - at least not that I have ever seen.

It's also not critical that you hit these exact numbers IMO. As long as you're in the ballpark and stable you'll be fine.

Personally, I would consider the following as good target ranges:
pH = 8.0-8.4
Ca = 400-450 ppm
Alk = 7-10dKH (2.5-3.5 meq/L)
SG = 1.025 - 1.026
S = 35-36 ppt

HTH