The advice given to me here is outstanding but, without intending to sound arrogant, I am free to use that advice along with my own ideas. UV lights are very good at removing bacteria and pathogens which are two things I don't want in my tank (the blue-green algae, I'm told, is a bacteria). Also, the reason I've avoided the 1000 LPH internals is the fact that they take up a lot of room. The 700-750 LPH internals are just the right size and the fact that the particular 750 LPH internal I bought also integrates a UV is a brilliant addition in my opinion.
I've seen quite a few reviews that state that UV has completely removed algae and cyanobacteria in peoples aquariums; just search 'cyanobacteria UV' on google and see for yourself. I don't mind spending £40 on the filter I've bought; I need to buy it and try it out before judging it to be a load of rubbish.
I don't think anyone was questioning the abilities of UV light. It was the LED UV that they were questioning. LED is pretty ambiguous in that you can get 3/5mm LEDsw chih are nigh on display only lights then there are the high power LEDs which are usable as direct replacements for flouro etc.
With your unit only consuming 8.5V including the LEDs I'm not so sure they are high power LEDs but the review I posted earlier did have succesful results.
At the end of the day not many of us use UV. I used to have an external one and of course I expect it did its job but then I can't confirm as I had no problem before, with or after selling it. I no longer have UV since mid 2007.
This increased LPH rate will supposedly help to remove the cyanobacteria both physically (it seems to have a free-floating stage) and also in terms of depriving nutrients from it.
You're still talking about removing nutrients

Try to pull yourself away from that way of thinking.
With a filter in the planted tank you have to see things slightly different.
It will be doing minimal work in removing nutrient in terms of ammonia. Plants will do that.
In a planted tank we need turnover to circulate nutrient, not remove it. so the filter provides circulation. Some may say 'why not just use a circaultion pump?' Well we use externals mostly and glass pipes or minimalistic outputs rather than equipment in the tank, so if we can avoid extra equipment in the tank we do.
The second are of a filter being incredibly useful in the planted tank is that with the aesthetics in mind the filter will remove all those particles and make the water much clearer. If it looks even the slightest bit 'foggier' (and I mean the very teeniest bit foggier) it bugs me. I want plants and fish at the back to be as crystal clear as those at the front. I want to look and see it as if there was no water in the tank. That is how clear I want the water to be and therefore the filter has to remove any teeny tiny particles that are not distinguishable to the naked eye but are obviously there if you can tell there is water in the tank.
So with that in mine the filter's media capacity is a very real factor. The more capacity the more media and therefore the more particles will be removed. That is why a high turnover filter with smaller media capacity isn't really what we look for, nor a high turnover filter with no media. If we were to consider look the latter then we may as well just use a powerhead without the media container on the bottom.
Saying that there are some that do not use filters. They often say their water is crystal clear however I would lay money that if they came and saw my tank they would walk away disappointed with what they considered crystal clear.
So all we are talking about in terms of the filtration improving conditions and making them unfavourable for the Cyano is the actual filtration capacity of the Cyaman versus a better filter. The larger turnover will draw more water in through the filter media and 'hopefully' remove more detritus. Keep the water clearer, let les settle on the substrate and surfaces etc. Its nothing to do with removing nutrient, just improving the water conditions via cleaning it better.
AC