300 Gallon Acrylic Restoration & System Build

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ZTheBaldGuy

Feeder Fish
MFK Member
Feb 22, 2016
28
13
3
Surprise, Arizona
I tried editing my original 450 gallon plywood tank build thread here but for whatever reason I wasn't able to change the title on it so I am creating a new thread to track the build progress on my 300 gallon acrylic aquarium I picked up yesterday.

I left off my 450 gallon plywood build thread with changing direction and using the materials to build a stand and saving up to buy an acrylic aquarium. So to that end, during some quiet time on Friday I googled dimensions for an 8 foot aquarium stand to get a feel for how tall I wanted to build to build the stand. I randomly came across an add for an acrylic 300 gallon aquarium for $500. Seemed like a great price on a large aquarium. On a whim, I texted the number to see if it was still available. I got a response that it was, so during lunch I drove from Phoenix over to Mesa to check out the tank.

Upon first glance the tank looked fine. It was dirty and would need some elbow grease to get it looking like new but it was doable without throwing too much money into it. Dimensions weren't exactly as I would have liked, 8ft Long x 2ft Wide x 2.5ft Tall. Would have preferred to have it wider than taller and also the overflow box was right smack in the middle of the tank as opposed to the corners or back of the tank. Still not a deal breaker, especially for $500.

Now here comes the kicker, this aquarium used to be a saltwater setup. For those of you wondering why that matters, it was designed with 2 plenum boxes, one on each side, as part of the biological filtration system. So in addition to the welded acrylic to the bottom creating the plenum area, there are also 4 holes drilled into the bottom of the aquarium that will need to be sealed. I guess that was part of the reason why the aquarium was such a bargain.

I talked to the guy, who suggested routing the acrylic down and then using bulkeads to seal the holes. I gave it some thought and figured I would have better luck dremiling then sanding until the plenum boxes were removed. Didn't seem like an impossible task so I decided to take the chance and bought the aquarium and loaded it up on the back of my truck. As an aside, I love having a full sized truck. It has allowed me to impulse buy stuff like crazy over the years.

To be continued in post #2.
 
I want to start off with some pics. Here it is on the back of my truck in the parking garage at work after I got back from lunch/picking up the aquarium from the seller.



On the way home from work, I stopped by Harbor Freight and picked up 2 moving platforms that I used to unload the aquarium from my truck, which I had to do on my own. The platforms worked great and allow me to move the aquarium around.

I had initially just planned to unload the aquarium and start on removing the plenum boxes starting the following morning but I noticed that for one of the holes in the plenum box, the gray pipe that was supposed to be there was missing. As if the force of some kind of impact had knocked it off the bottom. So I grabbed my 2 lbs plastic drop hammer and took a swing at the other pipe and sure enough it came off. I went over to the other side and knocked the other 2 pipes off the bottom too.

At that point I was left with just the plenum boxes and the baffles inside them. I wish I had taken better pictures to give you all an idea of how tall they were. But here are some pics:

This one has the plenum box with baffles. Pipes were already removed before the pic was taken.



The baffles were removed with just the outside plenum box in this pic. It is actually of the plenum box on the other side of the tank.



It took about 15 minutes of smacking the plenum boxes and baffles but they are mostly out at this point.





You can see that there are still pieces of acrylic attached to the bottom that will need to be sanded down but overall, it didn't take much effort to get the majority of the plenum boxes and baffles out.

I vacuumed up the crushed coral and acrylic pieces with my shop vac to clean up the bottom a little.



Here are a couple of pics of the overflow box and plumbing in the overflow box:





So on the bottom, it looks like there is one large hole for draining and one smaller hole as a return. On the overflow box itself, there are 2 holes drilled for returns, one on each side of the box.

The aquarium also came with a sump filter. I washed out most of the crud in it since it was giving off some nasty fumes. I'm not sure if I will end up using it or not. But here is a pic of the sump:



And here is a full tank shot showing where I left it at progress-wise at the end of the night:

 
The plan for today is to pick up a hand brush to knock the rest of the crushed coral gravel loose and shopvac it out. After that I will give the inside a good hosing down to get any remaining dirt out so that when I start sanding, I won't need to worry about pieces of crushed coral scratching up the tank.

So, in my mind, I have two options for sealing those plenum holes on the bottom.

1. Use bulkheads and then plug them on the top and bottom to seal them.

2. Buy some 3/4 acrylic squares and use weldon to weld the holes closed.

I feel like option #2 has the biggest potential to screw up the tank but option 1 can potentially leak at some point down the line. Any thoughts or opinions? Would love some input on this.
 
Got what I planned on getting done for the day completed already. Brushed the inside and then shop vacced it out. Then I rolled it out on the driveway and started hosing it down. I had to let all the gunk inside get wet and moisten up before it started to really come off. Then I hosed and scrubbed until it was fairly clean.

I'm pretty sure I scratched the inside with the brush I was using but I planned on buffing the inside and outside with Novus to clear it all up anyway. I was finally able to get a good look at the condition of the aquarium and quite frankly it looks pretty good! Much better than I anticipated.

At this point it is back in the garage drying out. Next step will be to sand down the last bits of the plenum. Depending on how long it takes to dry, it may be a project for next weekend.

I also think I will tie strap the aquarium down on the moving platforms to make it a bit more stable.

Here are some pics of the aquarium post cleaning:





 
Checked on the aquarium this morning to see if it had dried out. One half was dry while the other was still puddled with water.

I decided to start working on the bottom of the dry side so I started with my dremel and begin sanding the ridges. I found the dremel to be fairly ineffective and it tended to bounce around a lot due to chatter. Instead I plugged in my dewalt hammer drill and connected a sanding attachment to it and hit the bottom with 40 grit sand paper.

My main goal was to clean up the holes where I would need to install the bulkheads and ultimately plugs. There were ridges around these holes as the pipe I had knocked off with the 2 lbs hammer hadn't come off cleanly. I wasn't as concerned about the portions of the baffles and plenum boxes left but I did want to bring down any tall/sharp ridges. I figure the bottom will covered with gravel so if it looks scratched up, it won't really matter.

On another note, I don't have the longest arms in the world and I found it to be difficult working on the bottom of the aquarium due to the 30 inch height.

Some pics:

I actually started with the dremel before I took this pic but then stopped to take pic. I need to get into the habit of taking before and after pics.



Here is another shot after I cleaned up the 2 bulkhead holes and took the sharp ridges off the plenum/baffle material still stuck to the bottom.

 
I ordered some Novus 1/2/3 from Amazon this morning. The plan for next weekend is to sand the other side and then begin buffing out scratches with the Novus. The buffing may be a 2 weekend deal depending on how long it takes and how busy I am with other things.
 
Going into this weekend, I was pretty tired and also had a lot errands to get done so I decided to take it easy. I had originally planned on buffing out the scratches in the aquarium but decided to start working on the stand instead.

Started by cutting the 2x4 pieces to size.



Used a corner clamp to keep everything square while assembling the top and bottom frame boxes.



Completed the top and bottom frame boxes. The bottom has the cross bracing in. The top will need to wait until I can map out all of the bulkhead holes on the aquarium to make sure I don't install any cross bracing in the way.



Started installing the vertical pieces. I used clamps to hold them in place while I put in the screws.



This is where I ended for the weekend.



I will need to get a router bit to size the plywood for the bottom. Once that is installed and the top bracing put in on the top box then I can finish up the stand. I'm going to leave it open and not cover it with plywood so that I can have easy access to everything for maintenance.

Stand dimensions are/will be the following 96"L x 24"W x 32"H. The width between the inner vertical 2x4's is 18 inches.
 
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