Adding sand on top of argomite or go with a skimmer.

I have a 20 gallon hex minireef. At the very bottom is an inch of small gravel (came with the used tank and I
was a super newbie), on top of that I put a bag or argomite
that has taken up about 4 more inches. The tank is about nine months old. It has a Klarki Clown
a Jawfish (the argomite is tiny and he easily tunnels), a cleaner shrimp, emeral crab, several hermits,
a large turbo, two bummlebee snail, 6-9 astrea snails, a large blue shroom, a large beautiful feather duster
and some othe stuff on my LR I can not name but is getting larger. There is probably 25lbs of rock.
Since everything is vertical the rock is not far from from my lights, which now are two small 13w
PC, I built the canopy and the 15w florescent have out on me and I have not had time to fiddle with it.
The tank also has a small power head and a penquin power filter. I am wondering how
I can improve this reef with maybe LS or a skimmer, any tiny skimmmers out there that
you would reccomend to replace the penquin? I have algea problems, and have had two
red slime breakouts. Besides that everybody is happy. Thanks for your thoughts!


if you already have 4 inches of substrate i would leave that alone also with the jaw fish it will use the gravel in the sand to build and support its tunnels. they can use gravel, shell, small stone to do this far as skimmers a prizm may work well for your tank they are reasonably priced, hang on skimmer and easy to use and assemble. i dont think your pengin is causing your problem they are a pretty good filter.
as far as your alge problems
how are your nitrates?
do you over feed?
as for the cyano - do you have a pwr head in the tank?
cyano will grow in low circulated areas. the skimmer will help with that also.
how often do u do water changes? regular water changes can help rid u of it
with your tank being 9 mths old have you changed your light? lighting when it gets older can cause alge and cyano outbreaks because the spectrum of lights change