I looked at some other threads about pre-filters but didn't really address what I was looking for. I currently have 10 spas going for various kinds of testing. A couple of years ago I started using a HydroPure Metal Trap pre-filter because my source water is terrible. It doesn't look too bad and doesn't test high for metals but the spa filters end up coated in orange-brown "sediment" that will drop back into the spa if you remove the spa filter too quickly.
So I started using this pre-filter which slightly helps, but when I put it back on the hose after a period of non-use and turn on the water, I get a little initial burst of the orange-brown stuff out of it. So I always run the water a little before putting it in the spa. It does seem to be slowing down over time, so it must be catching something.
Anyway, it seems to me that if the pre-filter was working right, I wouldn't get that burst of stuff - it should stay back behind the filter media. Do any of these pre-filters work better than others? Most (including the Metal Trap one) look like they just stuffed a bunch of something inside a PVC pipe and put fittings on the ends. Could be a bunch of pillow stuffing and sand for all I know. Would be interesting to dissect a bunch of them but I'm not inclined to (yet).
So I started using this pre-filter which slightly helps, but when I put it back on the hose after a period of non-use and turn on the water, I get a little initial burst of the orange-brown stuff out of it. So I always run the water a little before putting it in the spa. It does seem to be slowing down over time, so it must be catching something.
Anyway, it seems to me that if the pre-filter was working right, I wouldn't get that burst of stuff - it should stay back behind the filter media. Do any of these pre-filters work better than others? Most (including the Metal Trap one) look like they just stuffed a bunch of something inside a PVC pipe and put fittings on the ends. Could be a bunch of pillow stuffing and sand for all I know. Would be interesting to dissect a bunch of them but I'm not inclined to (yet).
