Well I think the whole purpose of the filter is to get rid of nasty stuff in the water ie., keep the water clear and clean and decreasing the flow would probably defeat the purpose of keeping the water clean but would make my life easier.
I can't believe this post has gone into three pages. I thought maybe I should post what this algae (if that's what it is) looks like:
The first picture is just a piece I pulled out of the water and laid on a paper towel, It looks like brown cotton candy floating in the water and hangs off all decorations and all the plant leaves. This sample is about 1"x3". It's pretty big. I've seen a fish have to shake it's body to get it off his/her face. The 2nd picture is the bottom of an AqualClear basket after being in the filter overnight. I clean the bottom of the filter before I go to bed and it's just about the first thing I have to clean from at least 1 of the 3 filters the next morning. Today it was covering all the filters at least this much and this much is enough to reduce water flow to a trickle. At the same time (no picture) the intake tube is often covered with FrogBit or other vegetation - which is kind of part of having vegetation floating on top of the water - the fish love the coverage, the humans hate the mess - I've never found any foliage that is great at floating and providing coverage for the fish, but also stays out of filters uptake tubes. If anybody knows the best kind of foliage to use - let me know. The one thing I can say about frogbit is that it grows really fast and some of the fish (mainly my DoJo's) enjoy eating it.
So I guess the question is - would this clog up a canister filter to a point where it would stop the filtering of water (I want the water to get clean and this stuff gone) - if a canister filter handles large debris better than a HOB filter then I would consider it. Right now I just bought a size 70 AquaClear filter for my most problematic fish tank which is only 29 gallons, I have that size filter for my 50 gallon tank and it BY FAR is less problematic to deal with. I swear that intake tube can be covered with this brown stuff and frogbit and the water flow still isn't disturbed. It only slows the water flow when the basket gets covered.
Oh, and an aside - when you load a basket full of media, you load the sponge in first - so when the basket looks like the picture below the SPONGE is COVERED AND DRIPPING with this brown gunk ie., it ceases to be an effective filter medium, so even though it has good bacteria in it you want to run it under clean water and squeeze it out really good or throw it out and get a new sponge - so I loose the good bacteria that live in the filter. To compensate, I pour a capful of Tetra's brand of bacteria to jump start new tanks into cycling - I figure I'm just helping to repopulate what I lost by rinsing out the filter.
The only thing that disturbs me is that on one tank I have lost 5 Dwarf Gourami over a period of a week. When I tested the water it was PERFECT except it showed a Nitrite level of .50 ppm which probably would be enough to kill some fish but I'm also concerned that they may have that Dwarf Gourami virus some people have mentioned since ONLY dwarf Gourami have died. They were all purchased the same week from two different locations - one was the online store LiveAquaria , which I've bought from many times and the other was Petsmart. The were neon dwarf gourami, flame dwarf gourami and just "regular" dwarf gourami. This is half of the total number I purchased - and the dead bodies showed no sign of illness or damage - and I never saw them just before they died, so I can't describe any symptoms - they look in perfect condition, My assistant wasn't available and I struggle with water changes but I removed about 3 "jan-sized" buckets and then replaced the water with 4 "jan-sized" buckets due to evaporation in this 29 gallon tank. I haven't run a water test on any other tank yet, and this one tank is the only one with gourami. Hopefully my pathetic water change helped lower the nitrites a little bit. No deaths so far today.