I had a nitrasafe and it worked 100%. As my tap water had super high nitrate levels I needed to do something, it took it down to 0. It had to be recharged once a week though, which takes a few hours, but you can set it up to recharge and leave it to go on its own.
I have a Juwel and I use their Nitrate Removing Sponge. It has to be changed every 6 weeks. Some people don't like these sponges but I don't know why. I e-mailed Juwel to ask but they did not reply! So I am still in the dark on that one. According to the box it benefits the plants and the fish and I imagine they must have researched it.
They have been very helpful. I have the same problem as you Rodders, the nitrAte level of my tap water is way to high to start with and green hair algae is starting to grow. I think I'll give Nitrasafe a go. I was thinking I was going to have to start using RO water but if Nitrasafe works it will be a much easier and more ideal sollution.
I bought an Interpet Nitrasafe Nitrate sponge and it has been in my tank since Thursday night. I've just checked my nitrAte levels again and they are around 5 ppm.
Thanks very much for your help reducing my nitraAte levels. It was a cause for concern for me as they were around 50 ppm and I cant reduce them with water changes as the nitrAte level of my tap water is just as high! which is another worry.