Dom, I probably wouldn't put any rock back. If you did though, be sure to cook it. It wouldn't be a bad idea to have some in the area with the red algae. Keep good flow in the area.
Not so much remove the poly filter, but use it differently. Rather than using phosguard (which is pretty lousy IME), cut up a polypad or pura pad and put it in the second reactor. The way which you are using it, they are clogging very quickly. If you are replacing them as often as you would need to in your current application, it has to be getting very expensive. Keep an eye on your ALK. I'd bet a lot of money you are going to see a drop when you start running GFO.
Kathy,
The term fuge is used far too loosely in the hobby. A poorly maintained sump can be just as bad. Think of it like this, if a fuge is not properly maintained and loaded with detritus, it's like adding a dirty tank on to your system. People give far too much credit to algae for nutrient export when in actuality, they can't keep up with their own fuge enclosure, let alone what you are cycling through it from your main display.
Keep the cheato small is like keeping a plant in a pot. As the plant grows, you need to get a bigger pot so the plant roots have room to grow. When the cheato ball, or any algae used in fuges is kept small, it has room to grow and seems to grow faster. Growth takes energy. Nutrients we don't want are energy. Keep the ball small and tumbling so detritus can't settle in it. There are also issues like certain nutrients being limiting factors in growth, but I'm not going to go that far into it.
If you can cut off the flow to the refugium and simply remove the sand bed and all the water, I don't see any reason why you can't isolate the fuge, empty it. Put in new salt water and go from there. As far as sand in the display, there are those who remove it all at once and those who take their time. Both work. I chose the latter when I did a sand bed removal in a main display.
If you cannot gravity feed your skimmer (many cannot be gravity fed) you want to draw water from the very first chamber of your sump where display tank water overflows into it if at all possible.
Ok if you want photo's of people with sucessful tanks with fuges, go to the boston reefers site
http://www.bostonreefers.org/forums/. I'm sure you will find more than plenty of volunteers there to take photos of their tanks with fuges. You should really consider expanding your search worldwide instead of just saying no one in NY does it, thus it doesn't work.
There is nothing i hate more than the guy who joined the site this month and thinks he knows all of us, the work we have done in this hobby, what sites we are a part of and what I should do to better myself and my knowledge.
After all I posted in the thread, this is all you were able to come up with to comment on? We had a similar guy do the same thing on another thread. He never did post a pic. He never backed up his misinformation either. You happen to be repeating much of what he said.
If you are going to come in here and post advice, BACK IT UP like I do. Don't send me to a different web site. If you can't, then you should sit back and learn more before you give advice.
I never said my way is the right way or the only way, or that no one in NY does it, but I base it off of my own experience on what I have done on my own tanks and MANY others who have since removed their fuges. I've seen very successful tanks with fuges, but most of what we are looking at here are dirty sumps with lights on them. Dom clearly doesn't have room under his stand to run an appropriately sized refugium, so I feel it would be better for him to go without it.
Your advice here has been questionable. I can go to all the other web sites, read and then come here and parrot what they said too. We've had several members do it in the past.
I always say... go to a muscle car forum and you'll find a guy with a broken lawn mower and 3 screw drivers in his garage telling you how to rebuild an engine. All too often here and every other web site I'm a part of, we have people posting advice who have the equivalent sitting on their living room floors.