I've just got some Rowaphos (500ml, which it says will treat 200-400litres of water, so I'm going to put just over half in my 35gallon initially, then use the rest over the next couple of months), and I'm just wondering where to put it?
I have an Eheim external wet/dry canister filter, with 2 baskets of filter balls (eheifsubstrat) inside and the wet-dry cone on the outside.
Will the Rowaphos work if I fill a small filter-bag with it and take a few of the balls out of one of the baskets (so it will fit in) and put the bag in the basket? Where would you place the bag - in the middle, top or bottom of the filter balls?
Or, would you get 2 filter bags and fill them equally with the Rowaphos, half the required amount in each, and take a few balls out of each of the 2 Eheim baskets and put a filter bag in each basket?
Should the filter bags be packed tightly with Rowaphos, or should there be a bit of space in there?
And, if possible should I get a fairly large filter bag and spread the Rowaphos out in it, then stretch the bag over the whole of the top of the basket (so the water HAS to go through it), or will just having a small bag somewhere in the basket do the trick ok?