75 Standard versus 90 Gallon Tank Size

DrTed_Bulkhead

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SO... It has been years since we have revisited the old 75 gal standard versus 90 gal. What are your thoughts?

Consider in terms of your typical 75 TopFin, 90 Marineland, but beyond to 90 or 100 custom (drilled) as an option for rimless design. Value and effectiveness, I would appreciate any and all insights to help me decide and I am somewhat welcome to the idea of drilling and setting up the appropriate pump to do sump. This has been a back and forth over the ages 75 vs 90.

Obviously 90 is greater height at 24" or even 25 rimless height on some... but does a sumped 75 offer similar or better effective?

SO... I want you guys and gals to help me decide. Give me some convincing arguments one way or the other on which tank I should get.

Try to keep discussion to the 48" length tanks. I am familiar with the dimensions however there are many ways one could set such up in terms of hardware and filtration. Just figure filtration and suitable to be apples to apples. What do you use? I am very curious to others experience.

Drilling an expensive custom tank versus setting up an overflow box as clean as possible... im trying to keep it vague but any and all thoughts🤔 ...

~ Dr Ted Bulkhead
 
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I am not sure that I see where there is anything to debate, other than personal preference.

Both are the same length and width. The 90 simply has a few more inches of height.

That means a few inches more room for coral, aquascape, fish swimming area or whatever. It is not going to make much of a difference for lighting.

I think most people would prefer a drilled tank vs relying on any type of overflow that could lose its prime.
 
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Aren't the tanks mentioned the same footprint (48"x18") with the 90 just being about 4" taller,,, or did I miss something?
*I'd go with the shorter tank but that's just personal preference

Sump or not feels like an independent question (to me), regardless of 75 or 90 tank,,, again, unless I missed something.
*I don't have a sump but wish I did so I'd go with a sump,,, and would also go drilled over HOB overflow

Last thought is that I'd consider looking for something with more front-to-back room but still 48", if budget and space allows -- budget 120G, IM 100, etc.

Don't have any useful experience to offer <-- only responded with personal preferences since I'm considering upgrade from 3' to 4'-5' tank currently
 
Aren't the tanks mentioned the same footprint (48"x18") with the 90 just being about 4" taller,,, or did I miss something?
*I'd go with the shorter tank but that's just personal preference
Yep - I was thinking of the 48" 120. The standard 75 and 90 are the same footprint.
 
Personally I like tanks that are taller as it gives a better picture to view and gives the fish more vertical height to swim.
 
If this were me, I would go with the taller tank, less for the fact of more volume of water and more for the height of the tank. You can have taller rock work, coral, and different fish that swim at slightly different layers in the tank.

As for sump, I would recommend a sump regardless of if you choose 75 or 90. The ability to hide the equipment and add volume of water to the system is incredibly important, however I personally would only ever have a drilled tank. I would worry about an overflow loosing its siphon. I drilled my sump when I built it (however that was a little less worrisome than a tank, but had no problem with it as long as you are really slow and take your time. Much better to go too slow and use the proper water and drill bit than to crack the tank.
 
Basic question because yes they are the same footprint looking at 48x18.5 on either a 75 or a 90 gal. Mainly questioning the equipment and adding a sump?... better to drill a 90 gallon I suppose thats what is most being recommended over a siphon / HOB overflow box.

I would am a bit cringe on the idea of jumping straight to drilling holes and wondering about the propper Bulkhead. Is there any failures in such a design, leaks?

Right pump to setup to get propper flow?
Would want about 400 - 450 GPH?

I figured i would post here in Equipment, Filtration, and Hardware for some specifics or if anyone could point in the right direction to a thread already showing a sump setup for a 75 to 90 gal.
 
If this were me, I would go with the taller tank, less for the fact of more volume of water and more for the height of the tank. You can have taller rock work, coral, and different fish that swim at slightly different layers in the tank.

As for sump, I would recommend a sump regardless of if you choose 75 or 90. The ability to hide the equipment and add volume of water to the system is incredibly important, however I personally would only ever have a drilled tank. I would worry about an overflow loosing its siphon. I drilled my sump when I built it (however that was a little less worrisome than a tank, but had no problem with it as long as you are really slow and take your time. Much better to go too slow and use the proper water and drill bit than to crack the tank.

Great that you mentioned fish at different layers... could you expand on the species you would choose if going with a few layers? If you could pick just 3 layers lets just say, what would that become?

I would think for a drilled 90 would essentially be barely over 75 gallons is why I brought this question up. Once hardware, sand, and coral / rock are in place, offsetting water and the lowered 3/4" drill hole in place the REAL volume of water much lower than the 90 brought up.

Also how would this be for cleaning and maintenance? Fairly sure id need a stool but im hoping with a sump that i wont have to stand on stool for long.
 
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75 if you're short, 90 if you are tall.

I hate not being able to reach the back corners of the tank easily.
 
I upgraded from a 75g to a 90g. I was VERY happy with the change-up.
 
Hmm, okay well im gonna just drill a 90 gallon and call it a 75 with a sump. Not sure why this was much of a comparison. I guess in terms of a sump, now I do need the bigger 40 Gal, breeder size sump, rather than with a 75 I have in the past got away with just using a standard 20 gallon long with three baffles.

I do want my skimmer section running off and on carbon so its probably better to have the extra sump space.
 
I went from a 90 to 150 and have same issue. I cannot reach the bottom with my hand. One foot on the stand and other on the dining room table I can get it. Step stool not so much. 5'7" not a total stump.
Set up 75 and much better, make the stand taller so you are not looking down in the tank, gives more room to access sump as well.
The extra vertical space doesnt account for much unless growing a bunch of stags
 

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