Proper level of alk?? Effects of low and high readings??

[chuckdallas]

I was reading someone's thread the other day and they were saying they maintained their alk at 6-7 dKh. I don't remember if it was intentional or not.

Isn't the right alkalinity level supposed to be around 8-10?

What happens if alk stays in the range from 6-7 or 10-12 for extended periods of time?

[bertoni]

The usual recommended range here is 7-11 dKH. The ocean runs 6.3-6.9:

http://reefkeeping.com/issues/2005-11/rhf/index.php#3

We generally recommended keeping it at 7 dKH just so that daily fluctuations don't drop the level down too far. Many tanks see alkalinity shifts of 2-3 dKH per day without supplementation, so targeting a low level has some risk.

Higher levels don't seem to cause much trouble, at least over the long haul. In the past, people ran tanks at 18 dKH or so on a regular basis. Some tanks run with carbon dosing seem to have troubles with alkalinity much over 8 dKH.

[chuckdallas]

Thanks Jonathan. I thought 7 was low so I increased the time the doser was pushing out alk from 5 mins to 7 mins at 2 am and 4 am, and it has gone from 6.5 to about 8 dKh.

Will switch the time back to 5 or 6 mins at 2 am and 4 am.

[bertoni]

You're welcome!