I used to use SeaChem PhosGuard, but after hearing good things about Rowaphos I tried it and I think it works well but I wonder if it's worth the huge cost. The only benefit I can see to it is that they claim phosphate will not be reintroduced into the water if it's left in the waterflow after it's absorbed all it can, and it's apparently very efficient. Seachem claims the same things. I like being about to get a liter of Phosguard for about $10 verses something much more for SeaChem. Any experiences with these. To me it's easy to just replace the phosguard more frequently, the cost is still much less.