I'd just give it a good rinse and put it in the tank. I think it probably wouldn't be very dusty anyway, but always a good idea to at least rinse anything going into the tank.
It's usually a lot more inconvenient doing it that way, which is basically just a top mounted sump. With a sump you can usually hide the sump in the stand somewhere so you can't see it.
You could also have it plumbed through the wall into the room behind the tank if you put it in a spot so you can have the sump in a convenient closet. That way you could lift the sump up to the same height as the tank and not lose flow pumping uphill. You could also plumb it so the water level in the tank and sump are always the same. But...Not likely you'll be able to do that?
You'll definitely want to get the tank drilled with a couple overflows for the sump. Probably a good idea to make sure the holes are high enough that the water level will stay above the bottom edge of the lid...Err...Well, not above the lid, that would overflow it. But high enough that the top of the water doesn't show. Probably need minimum of 2 holes about an inch in diameter, not sure on that though.
I think I'd go with The Claw's suggestion of a VA 4900 is good. It might not be a bad idea to go with a pair of smaller pumps since there seems to be a HUGE jump in pump price going from 3000lph to 4000 might almost be cheaper, at least it was when I was looking at pond pumps.
How's your nitrate level? What kind of and how much lighting do you have?
Generally with brown algae more lighting helps a bit. But you'll need to add lights because I don't think you want the lights on for much more than 12 hours. But, if the tank is only a month old wait a bit for things to settle first.
You can try some vinegar on the rock. If it bubbles it's probably limestone. But...That wouldn't have raised the PH to 9. Nine is ridiculously high. You could probably almost pour an entire container of baking soda into a tank with neutral(PH 7) water and it wouldn't bring it up to 9. I'm thinking whoever did the test stuffed it up and you need to get it done again.
I'm not sure about borneo suckers, but try putting a leaf of spinach or lettuce in the tank. I know plecos, bristlenoses etc like it so a borneo sucker might too.
oops, yeah, 1.028.
Yeah, I've got a heater in there, but it's turned way down, right now it's set at 21°C because I wanted to make sure it WASN'T turning on. I'd intended to run it cool(not cold) to begin with, but I didn't realize the tank would run hotter now than it did as FW. It hasn't actually gotten into the 28s anyway, only up to about 27.3. I've taken off the glass tops and if it doesn't settle around 25° or lower I'll look into setting up some computer fans or something to blow across the water. If I'm going to have to get a chiller then I'm going to have to call the whole thing off.
I'm reasonably sure I'm not overfeeding the tank. I'm only putting in a tiny pinch of freeze dried plankton or about 1/4 cube of frozen brine shrimp every other day.
As far as not listening to advice, I'm doing the best I can to fit the advice into what I can do. If I fail then I fail, but I'd rather have at least given it a try.
He's still alive, hasn't been eating for the last couple days. I'm not sure if it's because the temperature is too high for him or not, but he was eating well when the temperature was staying around 24-25°. It's now around 26°-27° But, I also realized just a few hours ago that the hydrometer was hitting the top glass of the tank and being held down a little so I thought the SG was lower than it was. It was actually about 1.28 so i've been adding freshwater to bring that down. It was originally about 1.24. Whether that makes a difference or not, I don't know.
I need to get an ammonia test kit too. But at least the color on the useless Hagen kit doesn't seem to have changed any over the last week. Only casualties seem to be a couple snails, I'm not sure if they're dead or just have sealed themselves up in their shells.
Yeah, basically suggesting doubling it. It SHOULD be snug and if it was the glue that gave way then you need more area for the glued. It doesn't have to exactly be doubled up. Just an extra strip glued to the bottom of the original piece to give you more area to glue to the front and the back of the tank should work too.