Big tank filters… styles, types, and what works best

I got an incredible chance on a 250 gallon it’s been bored for a sump system, and the tank was custom made for it… I know nothing about big tank systems… can you help me???

The trapezoid baffles just have slots in the top, so without modification, only the water pulled from the top will be pulled down into the filter… I’m actually thinking about plugging the holes in the bottom and boring some smaller diameter holes near the bottom of the baffles and still using those chambers for drawing water out to the filters but admittedly know nothing of the style of filter it’s intended for… there are no pumps, so those would be needed, to use it as intended… it came with 2 smaller water drain tanks…

I’m a little worried about the bulk heads leaking after a while, on the bottom of the tank

I was actually thinking 2 of the Tidal 150’s for filters… but am open to suggestions

No suggestions have you seen the T-shirts that say “ I’m unsupervised… I know, it’s scary, but the possibilities are endless”

You guys are going to leave an out of the box thinker with a 250 gallon tank to his own devices….

Something strange is likely going to happen

A few here will agree with me but most won't. I wish the tank were not drilled for a sump but that can be covered with glass plates on both sides of the hole and good silicone. In my personal opinion, with a tank this size, I would go with nothing but under gravel filtration with, at least, two under gravel plates with each having two air risers, I would prefer three to four filter plates in this big of a tank. I would use air stones to raise water in one riser of each filter plate and a power head on the other riser of each plate. The risers with air stones cause surface agitation to to increase oxygen transfer and the power heads cause a high water flow through the substrate giving a higher filtration. There is just no filtration method that gives more surface area than under gravel and also it gives the largest area for good bacteria.

If you are planning a sand substrate you cannot use under gravel filtration. If you want substrate feeders such as plecos and/or corys most would say that you must use a sand substrate but that is not really true. You can use a water eroded river based small pebble substrate and it is, both, fine for under gravel filtration and bottom feeders.

Right now, I am thinking of plugging the holes… I thought about threading the hole and screwing in pvc plugs, with pvc weld on both the threads , and the plug… if screwed into in from the top, a flanged pvc plug could be used, and I think it would be permanently as water tight as the tank is…

If the chambers around the holes, had small holes drilled just up from the bottom, on the interior wall portion, the chambers could be filled with bio media, and one of the big 4 inch air stones like I used in the 250 gallon Tilapia tanks… this would cause water to rise, in those chambers, go in the new holes in the lower part, and out the slots, at the top that are already in the chambers, offering a good amount of airation and circulation through the bio media, unseen in those chambers ( they are already black plastic

The tank is already drilled at the top, with bulkhead’s attached, and 2 ball jointed inlet hoses, so if I used 2 large canister filters, I could go over the wall for the filter inlets, and position where needed, and hook the outlet to the hoses already attached to the top of the sidewall of the tank ( edit... the hoses are actually in the back, top corners )

I'm actually thinking about Whiffle Golf balls in the baffled chambers... or something of similar coarseness for biomedia, that would not plug up easily, & let those chambers handle the aeration, & the ammonia, & the canister filters remove any solids... so looking at bigger / better canister filters, most of which include a UV light... but some don't include pumps... so a bit to wade through there...

that basically is a 2 intake design with double intakes on both...
backup for a backup for a backup xDDD
if one intake gets plugged it has the 2nd one...both intakes have backup overflows for drainage
you can just put a sump under the main tank and pipe it however you want..make sure you have valves on both overflows not on the drain one
then comes noise factor...
you have 2 choices to reduce noise...you can use a gasket...shave a bit of one of it's sides and put on top of the hole..it'll create a vortex and reduce the noise
2nd choice...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 to the point of making noise again..adjust the drop flow on the ball valve
2nd option would run 100% silent if the intake grill wasn't all the way at the top
you will still have some noise from the water dropping from the grill
if using a canister...plug one of drain holes
on the left side have the water go into the canister right side back into the tank
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 power goes out
and since this tank is designed with backup of backup of backup...to keep it's ideal backup of backup...add a check valve on the return upright pipe
connect the left over drain hole into a drain and water changes should be done simply by adding water to the tank as it'll overflow into the drain

this is how high each pipe should be for a sump...
if going with a canister you don't need the backup for sump and can just plug it with a bulkhead

The tank has out side dimensions of 6 foot long, by 30 inches wide, & 30 inches tall... not sure of the exact gallon rating... guessing close to 250, with the tank being made of 3/4" acrylic

I don't have advise that would be useful, other than suggesting NOT to plug the wholes in a permanent manner (i.e., gluing). Instead, I would cap them if not interested in using them at this time.
That is a very nice tank, and there are many possibilities; you may find yourself changing your mind. So better to keep it flexible.
30 inches tall and 30 inches wide.... Very nice but it would be tricky to do regular maintenance/service, at least for somebody relatively short (like me).

Looking at big tank / pond canister filters / pumps / & combination units...

I'm liking this one right now...

but I'm open for suggestions in this area, & just how big they should be... I want to run 2 of them, so one can run, during service of the other looking at this one above, that's 800 to 1600 gallons per hour... I think that's big enough, since there would be 2 of them

thoughts???