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I just scored an amazing deal on a 250 gallon tank that's already been set up for a sump system - it was custom made for this exact purpose. Thing is, I'm totally new to big tank systems and I'm not really sure where to start... can someone walk me through this?

The trapezoid baffles have just slots at the top, so without modification, only top water will get pulled down into the filter. I'm thinking of plugging the holes at the bottom and boring smaller holes near the bottom of the baffles - still using those chambers for drawing water out to the filters, but I'm not really sure what style of filter it's meant for. No pumps, so those would be needed to use it as intended. Came with 2 smaller water drain tanks, which is a plus.

Concerned about the bulk heads leaking over time on the bottom of the tank, don't want that to happen. Considering 2 Tidal 150's for filters, but open to other ideas.

I've seen those "I'm unsupervised" tees - they're hilarious. You're basically handing over a 250-gallon canvas to a free thinker, and I'm pretty sure the outcome will be... interesting.

A few of you will probably agree with me, but I'm guessing most won't. I've got to say, I wish this tank wasn't set up for a sump system - but that's an easy fix. You can cover the holes with glass plates on both sides and seal it up with some good silicone.

My two cents, with a tank this size, is to go all in on under gravel filtration. I'd use at least two under gravel plates, each with two air risers - three or four plates would be even better. I'd use air stones in one riser on each plate to get some surface agitation going and increase oxygen transfer, and then throw a power head on the other riser to really get the water moving through the substrate. That way, you're getting some serious filtration going on. And let's be real, under gravel filtration gives you more surface area than any other method, and that's where the good bacteria live.

Now, if you're thinking about using sand, you can forget about under gravel filtration - it just won't work. But if you're looking to keep some substrate feeders like plecos or corys, you don't necessarily need sand. A water-eroded river pebble substrate is a great option - it's perfect for under gravel filtration and it's gentle enough for your bottom feeders.

I'm currently leaning towards sealing the holes, and I figure threading the hole and using PVC plugs with weld on both the threads and the plug would do the trick. If I screw it in from the top, a flanged PVC plug would be the way to go - I think it'd be as watertight as the tank itself.

If I drill small holes just above the bottom on the interior wall of the chambers, I could fill those with bio media and toss in one of the big 4-inch air stones, similar to what I used in my 250-gallon Tilapia tanks. This would cause water to rise in the chambers, flow into the new holes near the bottom, and exit through the existing top slots, providing decent aeration and circulation through the bio media hidden in those black plastic chambers.

Since the tank's already drilled at the top with bulkheads and ball-jointed inlet hoses attached, I could use two large canister filters, routing the inlets over the wall and positioning them as needed. Then I'd just hook the outlet to the existing hoses on the top of the sidewall - or rather, the back, top corners.

I've been considering using Whiffle Golf balls in the baffled chambers or something similar as biomedia - something that won't clog easily and can handle aeration, ammonia, and the like. Then, I'd use the canister filters to remove any solids. I'm looking into bigger, better canister filters, most of which come with a UV light, but some don't include pumps, so that's a bit of a challenge to navigate.

basically, I'm thinking of a 2 intake sump design, but I'm gonna do it my way - double intakes on both, with backup overflows for drainage. I mean, if one intake gets plugged, I've got a 2nd one, and both intakes have backup overflows, just in case. I can just put a sump under the main tank and pipe it however I want, as long as I've got valves on both overflows, but not on the drain one.

now, about the noise factor - I've got two choices to reduce the noise. I can use a gasket, shave a bit of one of its sides, and put it on top of the hole. It'll create a vortex and reduce the noise. or, I can put a 45 degree elbow on the top of the overflow and drill a hole on the top of the elbow. It'll gargle in the beginning, but once it gets going, it'll remove the air by itself and act as a full siphon. If the water level drops too much and starts making noise again, I can just adjust the drop flow on the ball valve.

if I'm using a canister, I'll plug one of the drain holes. I'll have the water go into the canister on the left side, and back into the tank on the right side. I'll put a PVC pipe up higher than the water level with a 90 degree elbow back into the water on the return, so there's no back flow in case the power goes out. and, since this tank is designed with backup of backup of backup, I'll add a check valve on the return upright pipe. I'll connect the leftover drain hole into a drain, and water changes should be a breeze - just add water to the tank, and it'll overflow into the drain.

if I were to go with a sump, I'd make sure each pipe is at the right height. but, if I'm using a canister, I can just plug the sump with a bulkhead and forget about it.

The tank's specs are 6 feet in length, 30 inches in width, and 30 inches in height, with an estimated gallon rating close to 250, considering it's made of 3/4" acrylic - the exact gallon rating is still a mystery.

I'm not going to pretend to be an expert here, but I do have one piece of advice - avoid plugging those holes permanently, like with glue. It's better to cap them if you don't plan on using them for now. That's a beautiful tank you've got there, and I'm sure you'll find plenty of uses for it. The thing is, you might change your mind later, so it's best to keep your options open.

I have to say, 30 inches tall and 30 inches wide is a great size, but maintenance could be a challenge, especially if you're not exactly tall.

I'm currently checking out some big tank and pond canister filters, pumps, and combo units. I'm really liking this particular one I found, but I'm all ears for suggestions on what I should be looking for in terms of size. I'm planning on running two of them, so I can service one while the other is still running. This one I'm looking at has a flow rate of 800 to 1600 gallons per hour - I think that's big enough, especially since I'll have two of them. What are your thoughts on this?