View Full Version : HOB Filter

05/07/2009, 03:55 PM
I want to lower my nitrates, which are about 15-20, and was thinking about removing my HOB filter and put it on my QT. Do I need to slowly reduce the use of the filter or can I just take it off?

05/07/2009, 04:08 PM
Depends on a LOT of things, such as the size of the filter, size of your tank (75g, right?), your bioload, and how much rock you have (just to name a few).

The safe route is to remove a portion of the filter media every couple of days, spread it out over a week or two.

If you have a very low bioload and at least 30-40 lbs of rock, you should be able to remove it entirely.

FWIW, The filter isn't the "source" of your nitrates. Now, junk accumulating in it can help metabolize trapped crud into nitrates, but that's handled by cleaning the material weekly.

You can leave the HOB in place but remove all the filter media if it is providing good water flow for certain corals. You can also use it as a small refugium, as some folks do, but on a 75, even the biggest HOB won't be of much use.

05/07/2009, 04:41 PM
There are no fish in tank. Lost some to ich and I left it empty over the last two months. Started qt about one week ago(should have about 9 months ago). I have about 90 lbs. live rock. Would like to put HOB on qt to add more water flow and volume than the little HOB that came with the 10g qt.