Help with a very complex aquarium setup?

Yes, you have to change the water. I can’t answer your questions as far as parts go and whatnot, but I would imagine it to be a risky idea to build a fish tank that can not be removed or significantly changed. If it springs a leak you’re going to be SOL.
Have you ever kept fish or a heated tank before?

@ANef_is_Enuf I have never had fish, it’s for a friend and he is taking forever to respond to me with these answers!

I wouldn’t recommend plexiglass. It clouds up over time and would be tough to clean. If you have a large enough tank (30 gallons) and it’s in balance water changes aren’t needed.

Keeping healthy fish requires frequent water changes. This article gives a nice synopsis of why and how.

You can do water changes, filtration, heating, and protein skimming via a set-up outside of the tank. Basically, a pump pulls water from the tank to a reservoir, usually below the tank (hidden), where it goes through the filtration and heaters. The clean water is then pumped back into the tank via a separate tube. These systems are called sump filters.

Before doing anything though, do your research. The more you know going into the job, the fewer problems you will have down the road. The web has tons of information on building, buying, setting-up, stocking and maintaining aquariums. Much more than you will get on Fluther. http://www.fishchannel.com/ is a good starting point. Good luck.

Being able to do water changes is important, as everyone else said.

You say it’s built into an entertainment center; I’m wondering if there will be loud music or anything coming out of the same structure that houses the fish tank? I can imagine that being very distressing to fish, just as tapping on the glass is.

If I were you I’d start experimenting with the weight of the completed apparatus on the entertainment center before doing a lot of construction of the tank.

Water weighs about 8.3 pounds per gallon. Your 40-gallon tank could weigh more than 350 pounds, considering the weight of the water, glass, bedding material and equipment installed. That’s a huge weight to place on the shelf of an “entertainment center” which typically doesn’t handle more than 25% of that kind of weight on a typical shelf. Then you have to consider the center of gravity and stability of this piece of furniture. You have a lot of engineering design to do.

As for the tank itself, you will eventually want “full access” to it while it is in operation. Aside from changing water (which you might have to do regardless of your filter quality if fish die or receive bad food), the owner will certainly need to do a thorough cleaning at some point, even if that point is years away at a future point of resale. If the tank can’t be cleaned then it will be junk.

I would not recommend “through the glass” plumbing. (I’ve never owned an aquarium, but I know boats.) The fewer through-hulls, the better. If you can arrange the plumbing to be done over the top of the glass, then you not only preserve the structural integrity of the tank better, but you make removal and replacement of equipment much easier in the future.

What is the dimension of your project tank? ... what is the available opening dimension of the entertainment center? You also have to consider the weight of the set-up, will the fixture hold up almost 450 lbs? How thick is the plexiglass you intend to use?

You might be better off getting a tank from the store, which are engineered to withstand the hydrostatic pressure on the glass and adhesive over several years.

Is it necessary to change the water? Yes, you will need to do periodic water changes. You will also need enough access so you can periodically check the water chemistry and/or change your filters, etc…

I can’t find the valve I need for this! Any idea where I could find it? Home Depot. You will need a pump to suck the water from the bucket up into your tank if I understand your plans correctly.

Is it ever needed to turn off the heater in the tank? Probably not if you have a heater with a built in thermostat. However, things tend to break over time so you need to plan on enough access to change out parts (see above).

How easy is it to build a fish tank? Not hard, but remember, water is heavy. Don’t expect to use a thin plexiglass and crappy silicon glue and expect it to hold together.

I’m just curious about the water changes. Is that with or without real plants? The best setup I came up with had real plants growing in the tank and I didn’t ever change the water. I sometimes had to get rid of some of the excess plants.

Live plants will remove the nitrates and prevent you from having to change the water. This, however, is a pretty delicate balance and as you point out, you will still have to be able to get into the aquarium to tend to the plants sometimes.

Thanks for all the response!

Could I possibly send you guys a google sketchup model of it so you could see whats going on?

I had a salt water tank for years and I did periodic partial water exchanges. That does not require too much access. But it does need to be vacuumed fairly regularly and for that you need access to the entire tank bottom. I didn’t have many fish just to keep it at minimum maintenance but even with just a few in a big tank, there is still work to be done now and again. It was very well balanced nonetheless needed a fair bit of work to keep it sparkling and clear. Having it built into a box where you cannot access it easily sounds like a definite pain!

@pikipupiba I’d love to see a Sketchup model, but only out of curiosity, because I don’t have the engineering expertise to critique it. I’ll tell you if anything jumps out at me, though.

Entertainment center? Like, electrical/electronic gizmos? That shouldn’t get wet or be somewhere with a lot of moisture? Doesn’t sound like a great idea to me…

If the Aquarium is not on the bottom, suggest you reconsider your design (as pointed out by @ccrow)

Yes you need to change the water, you also need to be able to turn off light…. it may get too warm in your home whether in the summer or from your heat in the winter so to keep from cooking the fish you will need to from time shut off the light. You also would need a way to keep the tank open so if it is too warm you can allow the heat to go somewhere. I don’t know if I would fully enclose it, you never know when a leak may happen. A friend made one in enclosed into his bar but at one point had a leak on one of the edges and because it was able to be removed he could locate the leak and fix it. So you would neeed to be able to have a way to be able to fix a leak otherwise you maybe ruining your floors while it leaked all over with no way to fix it. You also need to have a way of vacuuming out the debris on the bottom of the tank inbetween changing the water, and that means being able to put your arm from edge to edge of the tank to get out the poop. Then there are choices between fresh and salt water, I am not that knowlegable on salt water tanks but their care can be a bit different than fresh water.

How do I post the Sketchup model for all to view!?