I'm currently using Fauna Marin UltraPowerPhos , ?20 for 500ml , but you use much less of it as its absorbing qualities are that much better.
I've got a sample of UltiPhos XL from Ultimate Aquatics that they are trialling with UR members , that has had some good feedback. It is the next step from their UltiPhos P ... The blurb :-
Harder. P is great as it goes but it is a bit on the soft side and it tends to turn to dust if abused. So we've gone "hard as nails" with the new version.
Stronger. I got fed up of a certain phosphate remover having "unsurpassed phosphate binding power". So UltiPhos XL has around 3 to 5 times the binding capacity of P which is around 11g per kg as sold.
Cleaner. Pretty much dust free and dry so a dream to handle.
Cheaper. Twice the price of P but with 3 to 5 times the capacity. If you fluidise it in clean water then it is less than half the price of P per mg of phosphate removed. When you consider that P was already the cheapest per mg of phosphate removed that's a good saving.
And you can't go wrong with Muzzys (
www.tanktests.co.uk ) Phos 'n' Doc which is Po4 remover mixed with carbon so it's an all in one and it's a very good price. It's meant to go in a reactor , but i imagine it would be ok in an external.
Keep your friends close , but your anemones closer ....