First, sorry for the multiple cross-posts.
Second, sorry about the length.

I have a 55g Tall homemade tank that has about 3" of Laterite and
gravel mix. Tank has like 3-4 WPG and is moderately planted. About 9
months ago, with 2 angels and a pleco in the tank, the water turned
greyish-cloudy. Water changes did nothing. Nor did not feeding or
fertilizing or removing light, at least at first. After about 2 weeks
without light and food, the cloudiness cleared up. As soon as I fed
them again, it came back, full force. Things happened and I didn't
get to work with it until last month. Turns out one angel died. So
did several plants. I drained all but about 4" from the gravel down,
and removed the false rocks to be cleaned. I did leave some rocks
that I got from my back yard in there tho. After refilling, the water
was clear for about 3 days. By the third day it was slightly cloudy
again. Since, I can do a 25% - 40% water change at night and by the
next night it is cloudy again. Water has been tested several times by
the LFS and everything checks out fine. Added plants and filtration
and those are doing fine, I actually even get pearling after I water
change and the plants get light. Fish seem fine, and I had to add a
clown loach and a few tetras due to some other issues with another
tank. I have tried Formalin, at the recommendation of a friend. Also
tried changing food, removing the "real" rocks from my yard, and
Mardel's Clear Water. Nothing seems to work. Right now the only
problem is that the tank is cloudy when you want to watch the fish,
but I don't want to get any more fish until I get this sorted out.
ANY help is appreciated.

I thought it might be an algae bloom and asked to borrow my friends
diatom filter, but he doesn't think it's algae since it re-appears
overnight. I also changed to 2 Penguin Bio-Wheel 170's thinking it
might be bacterial and they needed a home.

Last time LFS checked water I had no Nitrates, Nitrites, barely any
Ammonia, proper salinity(if not a bit low, according to them), and
good KH and GH.

Thanks in advance.

T.