Polishing pads + Purigen and maybe decent water
OP: your original post said "How do you keep your water crystal clear." I'll share my experience and maybe it will save you some time. Most of this I picked up from this forum ...... except the micron polishing pads which I learned from a really knowledgeable
guy at Petsmart. I found that even using a walmart aqua-tech ..... with proper "cut to fit" customized media + Seachem Purigen ...... I got crystal clear polished water. Now, I use Fluval C series filters which are much easier to maintain while using 100 and/or 50 micron polishing pads.
You probably have more than one problem going on. Make sure your tap water is "fit" ........ mine is not. High phosphates and all kinds of things that are bad can be in some tap waters. I fought the battle for over a year until I did a change to 50% bottled spring water. I now use 40% bottled spring + 30% RO + 30% tap and have crystal clear and polished water.
I also use Poly-Filter by Poly-Bio-Marine to keep nitrates in check since I only do 20% weekly PWC's & gravel vacuum due to the expense and the "pain" involved in hauling one gallon jugs of $1 a gallon spring water and 27 cent a gallon refills of Culligen R/O drinking water one gallon at a time from Walmart to home ...... and then buckets of siphoned water from the aquarium to sink or garden. [Since I cannot use a Python or other syphon & fill device like most on this forum ..... that's why I stopped at two tanks.] You might give the Polly-Filter a one-time shot at least because it turns various colors depending on what impurities it removes.
http://www.amazon.com/Poly-Filter-3...TF8&qid=1397821177&sr=8-3&keywords=polyfilter
[I get mine from Drs Foster & Smith ... no shiping fee .... but their website is down right now]
******
That being said, assuming you have decent tap water (if so, consider yourself lucky), my "secret" to crystal clear polished water that looks like this (or better) at all times:
Aquarium Advice - Aquarium Forum Community - Paul1792's Album: Paul1792's 38 gallon - Picture
is micron polishing pads + Seachem Purigen.
If you go to the beginning of my 29 gallon tank photos album, you can watch as my 10 day "fish in" cycle "photo-diary" with seeded filter turned from cloudy to clear in nine days (fully cycled) .... then I put in the Seachem Purigen and the water went from clear to crystal clear which you can see in the first eight photos:
Aquarium Advice - Aquarium Forum Community - Paul1792's Album: Paul1792's 29 gallon
Here is what my micron media looks like after about a month:
Dirty Acurel Pad + 300 & 100 Micron AquatLife Pads Being Replaced With New Acurel Pad + 300, 100 & 50 Micron Pads. 3-19-14 Photo by Paul1792 | Photobucket
Although tightly packed floss will remove many micron particles and polish the water in your canister filter (I recommend SeraWool brand)
Amazon.com: Sera Filter Wool 3.5 oz: Pet Supplies
However, I suggest you (also) use 50-100 micron polishing pads such as these for Fluval canisters:
Hagen Fluval Fluval Water Polishing Pad - Fine Aquarium Filter Pads
Go here and see especially my post #2 where someone else had a problem similar to yours including "dead spots" which are a common filtration problem in bow-front tanks:
http://www.aquariumadvice.com/forums/f60/optimal-filtration-293808.html
OK ......... so ........ bottom line:
1) Check quality of tap water: Especially for phosphates which can promote algae growth/blooms.
2) Restrict lighting:.... watching out especially for direct or indirect sunlight. I found I had to put aquarium background on the side of my aquarium to restrict sunlight coming in over the "window" over my front door which faces east. (I had a horrible outbreak of black brush algae last year because of this).
3) Remove micron particles: Floss is good but 50-100 micron polishing pads are much better. Note: the first time you use micron pads, they clog quickly since you are removing particles that have built up over a long period of time. Once used on a regular basis ... they go at least a month.
4) Seachem Purigen:Works far better than carbon for chemical filtration.
5) Filtration: Make certain you have no "dead spots."
Good luck. I hope something I said helps someone in some way. I sure enjoy my crystal clear, polished water