Originally Posted by MizTanks
CPR Aquafuge. Mj400 106gph intake pump. 2" pink aragonite substrate. 18w cf 2 months old. No critters except for bristle worms/amphipods/copepods.
I've not touched it in any way as far as cleaning it out. But I really need to do it. It's just that's its so small that it would empty out in a minute via siphoning
A quick note on siphoning of small areas like this... a turkey baster is your friend, they can siphon a small area.
So... is it just the bulb that's two months old, or is it the entire HOB fuge
that's only two months old? If the whole fuge
is only two months old, I would propose to just leave it be, siphon out as much of the cyano as possible, and try to give it another month or two. If the fuge
is older, and just the bulb is newer, then the below could be considered as you wish.
First would be to remove the 2" of pink aragonite substrate and either leave that area empty and have just the chaeto in there, or replace it with only 1/2" of substrate, or at least a 4" deep bed with some extra critters. Cyano thrive in two types of environments in particular:
- Environments with a great deal of freely available PO4 / Phosphates, and
- anoxic environments in where freel available nitrogen is very depleted
With the 2" substrate bed you have in there, it is very possible that the entire bed in the fuge
has become an anoxic zone, especially with the low flow through the fuge
. With a shallower bed of 1/2", it will not be anoxic, rather, it will always be aerobic and less conducive to the growth of cyanobacteria. Conversely, with a 4+" substrate bed in the fuge
, the bottom several inches of the bed will become anoxic but there will be a better opportunity for the top 1/2" or so to maintain some aerobic activity, helping reduce a cyano-conducive environment. With the deeper bed, it would also be a good idea to add 2~4 nassarius snails or other sort of natural substrate sifter.
Other things to consider in general include:
PO4 levels... these can be brought down by feeding less or changing what you are feeding or skimming more heavily, slightly wetter than normal.
If that 18W CF bulb is a standard 10,000K bulb or similar, that's probably fine but if it is a generic cool white or warm white bulb from Home Depot, etc. the spectrum of the light probably isn't helping any.
The inlet compartment and outlet compartment of the fuge
... detritus can build up in those areas. As detritus breaks down, it can become a source of PO4. It is a good idea to siphon those areas out every water change.
Hope some of this helps... at least maybe it can spark some thought for consideration.