Join Date: Jul 2010
Location: Outside Philadelphia, PA
Over the years I have run UGF normally and reverse flow, on FW and SW tanks. At this point, I dpn't use them at all, although as you can see, there are some people out there that like them and still use them.
In my opinion, they work OK, but other more modern methods can work a lot better. Their one advantage I see is that they are very cheep to buy.
I found that in planted tanks, the roots really grew through the UGF plates and in time made any replanting difficult, because you would heavly damage the root system when you removed a plant.
What I do wonder is how you ended up with a 150 gal SW tank with a UGF. They haven't been common in SW tanks for something like 25+ years.
As for the "gravel" in SW tanks being reusable. This is usually either crushed coral, or aragonite sand or dolomite sand. All of these will add a lot of hardness to a FW tank and are best avoided for most systems. I would replace it.